November 2018 – GoldWiser Conroe

November 30, 2018

Coyote

The coyote (Canis latrans; from Nahuatl pronunciation (help·info)) is a canine native to North America. It is smaller than its close relative, the gray wolf, and slightly smaller than the closely related eastern wolf and red wolf. It fills much of the same ecological niche as the golden jackal does in Eurasia, though it is larger and more predatory, and is sometimes called the American jackal by zoologists.

The coyote is listed as least concern by the International Union for Conservation of Nature due to its wide distribution and abundance throughout North America, southwards through Mexico, and into Central America. The species is versatile, able to adapt to and expand into environments modified by humans. It is enlarging its range, with coyotes moving into urban areas in the Eastern U.S., and was sighted in eastern Panama (across the Panama Canal from their home range) for the first time in 2013.

As of 2005, 19 coyote subspecies are recognized. The average male weighs 8 to 20 kg (18 to 44 lb) and the average female 7 to 18 kg (15 to 40 lb). Their fur color is predominantly light gray and red or fulvous interspersed with black and white, though it varies somewhat with geography. It is highly flexible in social organization, living either in a family unit or in loosely knit packs of unrelated individuals. It has a varied diet consisting primarily of animal meat, including deer, rabbits, hares, rodents, birds, reptiles, amphibians, fish, and invertebrates, though it may also eat fruits and vegetables on occasion. Its characteristic vocalization is a howl made by solitary individuals. Humans are the coyote’s greatest threat, followed by cougars and gray wolves. In spite of this, coyotes sometimes mate with gray, eastern, or red wolves, producing “coywolf” hybrids. In the northeastern United States and eastern Canada, the eastern coyote (a larger subspecies, though still smaller than wolves) is the result of various historical and recent matings with various types of wolves. Genetic studies show that most North American wolves contain some level of coyote DNA.

The coyote is a prominent character in Native American folklore, mainly in the Southwestern United States and Mexico, usually depicted as a trickster that alternately assumes the form of an actual coyote or a man. As with other trickster figures, the coyote uses deception and humor to rebel against social conventions. The animal was especially respected in Mesoamerican cosmology as a symbol of military might. After the European colonization of the Americas, it was reviled in Anglo-American culture as a cowardly and untrustworthy animal. Unlike wolves (gray, eastern, or red), which have undergone an improvement of their public image, attitudes towards the coyote remain largely negative.

Coyote males average 8 to 20 kg (18 to 44 lb) in weight, while females average 7 to 18 kg (15 to 40 lb), though size varies geographically. Northern subspecies, which average 18 kg (40 lb), tend to grow larger than the southern subspecies of Mexico, which average 11.5 kg (25 lb). Body length ranges on average from 1.0 to 1.35 m (3 ft 3 in to 4 ft 5 in), and tail length 40 cm (16 in), with females being shorter in both body length and height. The largest coyote on record was a male killed near Afton, Wyoming, on November 19, 1937, which measured 1.5 m (4 ft 11 in) from nose to tail, and weighed 34 kg (75 lb). Scent glands are located at the upper side of the base of the tail and are a bluish-black color.

The color and texture of the coyote’s fur varies somewhat geographically. The hair’s predominant color is light gray and red or fulvous, interspersed around the body with black and white. Coyotes living at high elevations tend to have more black and gray shades than their desert-dwelling counterparts, which are more fulvous or whitish-gray. The coyote’s fur consists of short, soft underfur and long, coarse guard hairs. The fur of northern subspecies is longer and denser than in southern forms, with the fur of some Mexican and Central American forms being almost hispid (bristly). Generally, adult coyotes (including coywolf hybrids) have a sable coat color, dark neonatal coat color, bushy tail with an active supracaudal gland, and a white facial mask. Albinism is extremely rare in coyotes; out of a total of 750,000 coyotes killed by federal and cooperative hunters between March 22, 1938, and June 30, 1945, only two were albinos.

The coyote is typically smaller than the gray wolf, but has longer ears and a relatively larger braincase, as well as a thinner frame, face, and muzzle. The scent glands are smaller than the gray wolf’s, but are the same color.^[7] Its fur color variation is much less varied than that of a wolf. The coyote also carries its tail downwards when running or walking, rather than horizontally as the wolf does.

Coyote tracks can be distinguished from those of dogs by their more elongated, less rounded shape. Unlike dogs, the upper canines of coyotes extend past the mental foramina.

At the time of the European colonization of the Americas, coyotes were largely confined to open plains and arid regions of the western half of the continent. In early post-Columbian historical records, distinguishing between coyotes and wolves is often difficult. One record from 1750 in Kaskaskia, Illinois, written by a local priest, noted that the “wolves” encountered there were smaller and less daring than European wolves. Another account from the early 1800s in Edwards County mentioned wolves howling at night, though these were likely coyotes. This species was encountered several times during the Lewis and Clark Expedition (1804–1806), though it was already well known to European traders on the upper Missouri. Lewis, writing on 5 May 1805, in northeastern Montana, described the coyote in these terms:

The small woolf or burrowing dog of the prairies are the inhabitants almost invariably of the open plains; they usually ascociate in bands of ten or twelve sometimes more and burrow near some pass or place much frequented by game; not being able alone to take deer or goat they are rarely ever found alone but hunt in bands; they frequently watch and seize their prey near their burrows; in these burrows they raise their young and to them they also resort when pursued; when a person approaches them they frequently bark, their note being precisely that of the small dog. They are of an intermediate size between that of the fox and dog, very active fleet and delicately formed; the ears large erect and pointed the head long and pointed more like that of the fox; tale long … the hair and fur also resembles the fox, tho’ is much coarser and inferior. They are of a pale redish-brown colour. The eye of a deep sea green colour small and piercing. Their [claws] are reather longer than those of the ordinary wolf or that common to the Atlantic states, none of which are to be found in this quarter, nor I believe above the river Plat.

The coyote was first scientifically described by naturalist Thomas Say in September 1819, on the site of Lewis and Clark’s Council Bluffs, fifteen miles up the Missouri River from the mouth of the Platte during a government-sponsored expedition with Major Stephen Long. He had the first edition of the Lewis and Clark journals in hand, which contained Biddle’s edited version of Lewis’s observations dated 5 May 1805. His account was published in 1823. Say was the first person to document the difference between a “prairie wolf” (coyote) and on the next page of his journal a wolf which he named Canis nubilus (Great Plains wolf). Say described the coyote as:

Canis latrans. Cinereous or gray, varied with black above, and dull fulvous, or cinnamon; hair at base dusky plumbeous, in the middle of its length dull cinnamon, and at tip gray or black, longer on the vertebral line; ears erect, rounded at tip, cinnamon behind, the hair dark plumbeous at base, inside lined with gray hair; eyelids edged with black, superior eyelashes black beneath, and at tip above; supplemental lid margined with black-brown before, and edged with black brown behind; iris yellow; pupil black-blue; spot upon the lachrymal sac black-brown; rostrum cinnamon, tinctured with grayish on the nose; lips white, edged with black, three series of black seta; head between the ears intermixed with gray, and dull cinnamon, hairs dusky plumbeous at base; sidespaler than the back, obsoletely fasciate with black above the legs; legs cinnamon on the outer side, more distinct on the posterior hair: a dilated black abbreviated line on the anterior ones near the wrist; tail bushy, fusiform, straight, varied with gray and cinnamon, a spot near the base above, and tip black; the tip of the trunk of the tail, attains the tip of the os calcis, when the leg is extended; beneath white, immaculate, tail cinnamon towards the tip, tip black; posterior feet four toed, anterior five toed.

The earliest written reference to the species comes from the naturalist Francisco Hernández’s Plantas y Animales de la Nueva España (1651), where it is described as a “Spanish fox” or “jackal”. The first published usage of the word “coyote” (which is a Spanish borrowing of its Nahuatl name coyōtl) comes from the historian Francisco Javier Clavijero‘s Historia de México in 1780. The first time it was used in English occurred in William Bullock‘s Six months’ residence and travels in Mexico (1824), where it is variously transcribed as cayjotte and cocyotie. The word’s spelling was standardized as “coyote” by the 1880s. Alternative English names for the coyote include “prairie wolf”, “brush wolf”, “cased wolf”, “little wolf” and “American jackal”. Its binomial name Canis latrans translates to “barking dog”, a reference to the many vocalizations they produce.

November 29, 2018

Eagle

Eagle is the common name for many large birds of prey of the family Accipitridae. Eagles belong to several groups of genera, not all of which are closely related. Most of the 60 species of eagle are from Eurasia and Africa.^[1]Outside this area, just 14 species can be found—2 in North America, 9 in Central and South America, and 3 in Australia.

Eagles are large, powerfully built birds of prey, with heavy heads and beaks. Even the smallest eagles, such as the booted eagle (Aquila pennata), which is comparable in size to a common buzzard (Buteo buteo) or red-tailed hawk(B. jamaicensis), have relatively longer and more evenly broad wings, and more direct, faster flight – despite the reduced size of aerodynamic feathers. Most eagles are larger than any other raptors apart from some vultures. The smallest species of eagle is the South Nicobar serpent eagle (Spilornis klossi), at 450 g (0.99 lb) and 40 cm (16 in). The largest species are discussed below. Like all birds of prey, eagles have very large, hooked beaks for ripping flesh from their prey, strong, muscular legs, and powerful talons. The beak is typically heavier than that of most other birds of prey. Eagles’ eyes are extremely powerful. It is estimated that the martial eagle, whose eye is more than twice as long as a human eye, has a visual acuity 3.0 to 3.6 times that of humans. This acuity enables eagles to spot potential prey from a very long distance.^[2] This keen eyesight is primarily attributed to their extremely large pupils which ensure minimal diffraction (scattering) of the incoming light. The female of all known species of eagles is larger than the male.^[3]^[4]

Eagles normally build their nests, called eyries, in tall trees or on high cliffs. Many species lay two eggs, but the older, larger chick frequently kills its younger sibling once it has hatched. The dominant chick tends to be a female, as they are bigger than the male. The parents take no action to stop the killing.^[5]^[6]

Due to the size and power of many eagle species, they are ranked at the top of the food chain as apex predators in the avian world. The type of prey varies by genus. The Haliaeetus and Ichthyophaga eagles prefer to capture fish, though the species in the former often capture various animals, especially other water birds, and are powerful kleptoparasites of other birds. The snake and serpent eagles of the genera Circaetus, Terathopius, and Spilornis predominantly prey on the great diversity of snakes found in the tropics of Africa and Asia. The eagles of the genus Aquila are often the top birds of prey in open habitats, taking almost any medium-sized vertebrate they can catch. Where Aquila eagles are absent, other eagles, such as the buteonine black-chested buzzard-eagle of South America, may assume the position of top raptorial predator in open areas. Many other eagles, including the species-rich genus Spizaetus, live predominantly in woodlands and forest. These eagles often target various arboreal or ground-dwelling mammals and birds, which are often unsuspectingly ambushed in such dense, knotty environments. Hunting techniques differ among the species and genera, with some individual eagles having engaged in quite varied techniques based their environment and prey at any given time. Most eagles grab prey without landing and take flight with it, so the prey can be carried to a perch and torn apart.^[7]

The bald eagle is noted for having flown with the heaviest load verified to be carried by any flying bird, since one eagle flew with a 6.8 kg (15 lb) mule deer fawn.^[8] However, a few eagles may target prey considerably heavier than themselves; such prey is too heavy to fly with, thus it is either eaten at the site of the kill or taken in pieces back to a perch or nest. Golden and crowned eagles have killed ungulates weighing up to 30 kg (66 lb) and a martial eagle even killed a 37 kg (82 lb) duiker, 7–8 times heavier than the preying eagle.^[7]^[9]Authors on birds David Allen Sibley, Pete Dunne, and Clay Sutton described the behavioral difference between hunting eagles and other birds of prey thus (in this case the bald and golden eagles as compared to other North American raptors):^[10]

They have at least one singular characteristic. It has been observed that most birds of prey look back over their shoulders before striking prey (or shortly thereafter); predation is after all a two-edged sword. All hawks seem to have this habit, from the smallest kestrel to the largest Ferruginous – but not the Eagles.

Among the eagles are some of the largest birds of prey: only the condors and some of the Old World vultures are markedly larger. It is regularly debated which should be considered the largest species of eagle. They could be measured variously in total length, body mass, or wingspan. Different lifestyle needs among various eagles result in variable measurements from species to species. For example, many forest-dwelling eagles, including the very large harpy eagle, have relatively short wingspans, a feature necessary for being able to maneuver in quick, short bursts through densely forested habitats.^[7] Eagles in the genus Aquila, though found almost strictly in open country, are superlative soarers, and have relatively long wings for their size.

Eagles are often informally divided into four groups.^{[note 1]}^[18]

The snake eagles are placed in the subfamily Circaetinae. The fish eagles, booted eagles, and harpy eagles have traditionally been placed in the subfamily Buteoninae together with the buzzard-hawks (buteonine hawks) and harriers. Some authors may treat these groups as tribes of the Buteoninae; Lerner & Mindell^[19] proposed separating the eagle groups into their own subfamilies of Accipitridae.

Fish eagles

Sea eagles or fish eagles take fish as a large part of their diets, either fresh or as carrion.

Proposed subfamily Haliaeetinae. Genera: Haliaeetus, Ichthyophaga.

Some authors include Gypohierax angolensis, the “vulturine fish eagle” (also called the palm-nut vulture) in this group.^[18] However, genetic analyses indicate it is related to a grouping of Neophron–Gypaetus–Eutriorchis (Egyptian vulture, bearded vulture (lammergeier), and Madagascan serpent eagle).^[20]

The fish eagles have a close genetic relationship with Haliastur and Milvus; the whole group is only distantly related to the Buteo group.^[20]

Booted eagles

For the species Hieraaetus pennatus (Aquila pennata), see booted eagle.

Main article: Booted eagles

Booted eagles or “true eagles”^[18]^[21] have feathered tarsi (lower legs).

Tribe Aquililae or proposed subfamily Aquilinae. Genera: Aquila, Hieraaetus; Spizaetus, Oroaetus, Spizastur; Nisaetus;^[20] Ictinaetus, Lophoaetus; Polemaetus; and Stephanoaetus.^[18]^[21]

See comments under eagle species for changes to the composition of these genera.

Snake eagles

Snake or serpent eagles are, as the name suggests, adapted to hunting reptiles.

Subfamily Circaetinae. Genera: Circaetus, Spilornis, Dryotriorchis, Terathopius.^[18]

Eutriorchis (subfamily Gypaetinae or Circaetinae).

Despite filling the niche of a snake eagle, genetic studies suggest that the Madagascan serpent eagle Eutriorchis is not related.^[20]

Harpy eagles

Harpy eagles^[18] or “giant forest eagles”^[17] are large eagles that inhabit tropical forests. The group contains two to six species, depending on the author. Although these birds occupy similar niches, and have traditionally been grouped together, they are not all related: the solitary eagles are related to the black-hawks, and the Philippine eagle to the snake eagles.

Harpy eagles (proposed subfamily Harpiinae)

Harpia harpyja, harpy eagle ― Central and South America.

Morphnus guianensis, crested eagle ― Central and South America.

Harpyopsis novaeguineae, Papuan eagle ― New Guinea.

Philippine eagle

Pithecophaga jefferyi, Philippine eagle ― Philippines.

Solitary eagles

Chaco eagle or crowned solitary eagle, Buteogallus (formerly Harpyhaliaetus) coronatus ― South America.

Solitary eagle or montane solitary eagle, Buteogallus (formerly Harpyhaliaetus) solitarius ― South America.

Among the eagles are some of the largest birds of prey: only the condors and some of the Old World vultures are markedly larger. It is regularly debated which should be considered the largest species of eagle. They could be measured variously in total length, body mass, or wingspan. Different lifestyle needs among various eagles result in variable measurements from species to species. For example, many forest-dwelling eagles, including the very large harpy eagle, have relatively short wingspans, a feature necessary for being able to maneuver in quick, short bursts through densely forested habitats.^[7] Eagles in the genus Aquila, though found almost strictly in open country, are superlative soarers, and have relatively long wings for their size.^[7]
These lists of the top five eagles are based on weight, length, and wingspan, respectively. Unless otherwise noted by reference, the figures listed are the median reported for each measurement in the guide Raptors of the World^[11] in which only measurements that could be personally verified by the authors were listed.^[7]

Rank Common name Scientific name Body mass

1 Steller’s sea eagle Haliaeetus pelagicus 6.7 kilograms (15 lb)

2 Philippine eagle Pithecophaga jefferyi 6.35 kg (14.0 lb)

3 Harpy eagle Harpia harpyja 5.95 kg (13.1 lb)

4 White-tailed eagle Haliaeetus albicilla 4.8 kg (11 lb)^[12]

5 Martial eagle Polemaetus bellicosus 4.6 kg (10 lb)^[12]

Rank Common name Scientific name Total length

1 Philippine eagle Pithecophaga jefferyi 100 cm (3 ft 3 in)^[13]

2 Harpy eagle Harpia harpyja 98.5 cm (3 ft 3 in)

3 Wedge-tailed eagle Aquila audax 95.5 cm (3 ft 2 in)

4 Steller’s sea eagle Haliaeetus pelagicus 95 cm (3 ft 1 in)

5 Crowned eagle Stephanoaetus coronatus 87.5 cm (2 ft 10 in)

Rank Common name Scientific name Median wingspan

1 Philippine eagle Pithecophaga jefferyi 220 cm (7 ft 3 in)

2 White-tailed eagle Haliaeetus albicilla 218.5 cm (7 ft 2 in)

3 Steller’s sea eagle Haliaeetus pelagicus 212.5 cm (7 ft 0 in)

4 Wedge-tailed eagle Aquila audax 210 cm (6 ft 11 in)^[14]^[15]

5 Golden eagle Aquila chrysaetos 207 cm (6 ft 9 in)

6 Martial eagle Polemaetus bellicosus 206.5 cm (6 ft 9 in)

Rank	Common name	Scientific name	Body mass
1	Steller’s sea eagle	Haliaeetus pelagicus	6.7 kilograms (15 lb)
2	Philippine eagle	Pithecophaga jefferyi	6.35 kg (14.0 lb)
3	Harpy eagle	Harpia harpyja	5.95 kg (13.1 lb)
4	White-tailed eagle	Haliaeetus albicilla	4.8 kg (11 lb)^[12]
5	Martial eagle	Polemaetus bellicosus	4.6 kg (10 lb)^[12]

Rank	Common name	Scientific name	Total length
1	Philippine eagle	Pithecophaga jefferyi	100 cm (3 ft 3 in)^[13]
2	Harpy eagle	Harpia harpyja	98.5 cm (3 ft 3 in)
3	Wedge-tailed eagle	Aquila audax	95.5 cm (3 ft 2 in)
4	Steller’s sea eagle	Haliaeetus pelagicus	95 cm (3 ft 1 in)
5	Crowned eagle	Stephanoaetus coronatus	87.5 cm (2 ft 10 in)

Rank	Common name	Scientific name	Median wingspan
1	Philippine eagle	Pithecophaga jefferyi	220 cm (7 ft 3 in)
2	White-tailed eagle	Haliaeetus albicilla	218.5 cm (7 ft 2 in)
3	Steller’s sea eagle	Haliaeetus pelagicus	212.5 cm (7 ft 0 in)
4	Wedge-tailed eagle	Aquila audax	210 cm (6 ft 11 in)^[14]^[15]
5	Golden eagle	Aquila chrysaetos	207 cm (6 ft 9 in)
6	Martial eagle	Polemaetus bellicosus	206.5 cm (6 ft 9 in)

November 28, 2018

Owl

Owls are birds from the order Strigiformes, which includes about 200 species of mostly solitary and nocturnal birds of prey typified by an upright stance, a large, broad head, binocular vision, binaural hearing, sharp talons, and feathers adapted for silent flight. Exceptions include the diurnal northern hawk-owl and the gregarious burrowing owl.

Owls hunt mostly small mammals, insects, and other birds, although a few species specialize in hunting fish. They are found in all regions of the Earth except polar ice caps and some remote islands.

Owls are divided into two families: the true (or typical) owl family, Strigidae, and the barn-owl family, Tytonidae.

Owls possess large, forward-facing eyes and ear-holes, a hawk-like beak, a flat face, and usually a conspicuous circle of feathers, a facial disc, around each eye. The feathers making up this disc can be adjusted to sharply focus sounds from varying distances onto the owls’ asymmetrically placed ear cavities. Most birds of prey have eyes on the sides of their heads, but the stereoscopic nature of the owl’s forward-facing eyes permits the greater sense of depth perception necessary for low-light hunting. Although owls have binocular vision, their large eyes are fixed in their sockets—as are those of most other birds—so they must turn their entire heads to change views. As owls are farsighted, they are unable to clearly see anything within a few centimeters of their eyes. Caught prey can be felt by owls with the use of filoplumes—hairlike feathers on the beak and feet that act as “feelers”. Their far vision, particularly in low light, is exceptionally good.

Owls can rotate their heads and necks as much as 270°. Owls have 14 neck vertebrae compared to seven in humans, which makes their necks more flexible. They also have adaptations to their circulatory systems, permitting rotation without cutting off blood to the brain: the foramina in their vertebrae through which the vertebral arteries pass are about 10 times the diameter of the artery, instead of about the same size as the artery as in humans; the vertebral arteries enter the cervical vertebrae higher than in other birds, giving the vessels some slack, and the carotid arteries unite in a very large anastomosis or junction, the largest of any bird’s, preventing blood supply from being cut off while they rotate their necks. Other anastomoses between the carotid and vertebral arteries support this effect.

The smallest owl—weighing as little as 31 g (1 oz) and measuring some 13.5 cm (5 in)—is the elf owl (Micrathene whitneyi). Around the same diminutive length, although slightly heavier, are the lesser known long-whiskered owlet(Xenoglaux loweryi) and Tamaulipas pygmy owl (Glaucidium sanchezi). The largest owls are two similarly sized eagle owls; the Eurasian eagle-owl (Bubo bubo) and Blakiston’s fish owl (Bubo blakistoni). The largest females of these species are 71 cm (28 in) long, have 54 cm (21 in) long wings, and weigh 4.2 kg (9.3 lb).

Different species of owls produce different sounds; this distribution of calls aids owls in finding mates or announcing their presence to potential competitors, and also aids ornithologists and birders in locating these birds and distinguishing species. As noted above, their facial discs help owls to funnel the sound of prey to their ears. In many species, these discs are placed asymmetrically, for better directional location.

Owl plumage is generally cryptic, although several species have facial and head markings, including face masks, ear tufts, and brightly coloured irises. These markings are generally more common in species inhabiting open habitats, and are thought to be used in signaling with other owls in low-light conditions

Eyesight is a particular characteristic of the owl that aids in nocturnal prey capture. Owls are part of a small group of birds that live nocturnally, but do not use echolocation to guide them in flight in low-light situations. Owls are known for their disproportionally large eyes in comparison to their skulls. An apparent consequence of the evolution of an absolutely large eye in a relatively small skull is that the eye of the owl has become tubular in shape. This shape is found in other so-called nocturnal eyes, such as the eyes of strepsirrhine primates and bathypelagic fishes. Since the eyes are fixed into these sclerotic tubes, they are unable to move the eyes in any direction.Instead of moving their eyes, owls swivel their heads to view their surroundings. Owls’ heads are capable of swiveling through an angle of roughly 270°, easily enabling them to see behind them without relocating the torso. This ability keeps bodily movement at a minimum, thus reduces the amount of sound the owl makes as it waits for its prey. Owls are regarded as having the most frontally placed eyes among all avian groups, which gives them some of the largest binocular fields of vision. However, owls are farsighted and cannot focus on objects within a few centimeters of their eyes.^[16]^[18] While owls are commonly believed to have great nocturnal vision due to their large (thus very light-gathering) eyes and pupils and/or extremely sensitive rod receptors, the true cause for their ability to see in the night is due to neural mechanisms which mediate the extraction of spatial information gathered from the retinal image throughout the nocturnal luminance range. These mechanisms are only able to function due to the large-sized retinal image. Thus, the primary nocturnal function in the vision of the owl is due to its large posterior nodal distance; retinal image brightness is only maximized to the owl within secondary neural functions. These attributes of the owl cause its nocturnal eyesight to be far superior to that of its average prey.

Owls exhibit specialized hearing functions and ear shapes that also aid in hunting. They are noted for asymmetrical ear placements on the skull in some genera. Owls can have either internal or external ears, both of which are asymmetrical. Asymmetry has not been reported to extend to the middle or internal ear of the owl. Asymmetrical ear placement on the skull allows the owl to pinpoint the location of its prey. This is especially true for strictly nocturnal species such as the barn owls Tyto or Tengmalm’s owl. With ears set at different places on its skull, an owl is able to determine the direction from which the sound is coming by the minute difference in time that it takes for the sound waves to penetrate the left and right ears. The owl turns its head until the sound reaches both ears at the same time, at which point it is directly facing the source of the sound. This time difference between ears is a matter of about 0.00003 seconds, or 30 millionths of a second. Behind the ear openings are modified, dense feathers, densely packed to form a facial ruff, which creates an anterior-facing, concave wall that cups the sound into the ear structure. This facial ruff is poorly defined in some species, and prominent, nearly encircling the face, in other species. The facial disk also acts to direct sound into the ears, and a downward-facing, sharply triangular beak minimizes sound reflection away from the face. The shape of the facial disk is adjustable at will to focus sounds more effectively.

The coloration of the owl’s plumage plays a key role in its ability to sit still and blend into the environment, making it nearly invisible to prey. Owls tend to mimic the colorations and sometimes even the texture patterns of their surroundings, the common barn owl being an exception. Nyctea scandiaca, or the snowy owl, appears nearly bleach-white in color with a few flecks of black, mimicking their snowy surroundings perfectly. Likewise, the mottled wood-owl (Strix ocellata) displays shades of brown, tan, and black, making the owl nearly invisible in the surrounding trees, especially from behind. Usually, the only tell-tale sign of a perched owl is its vocalizations or its vividly colored eyes.

Most owls are nocturnal, actively hunting their prey in darkness. Several types of owls, however, are crepuscular—active during the twilight hours of dawn and dusk; one example is the pygmy owl (Glaucidium). A few owls are active during the day, also; examples are the burrowing owl (Speotyto cunicularia) and the short-eared owl (Asio flammeus).

Much of the owls’ hunting strategy depends on stealth and surprise. Owls have at least two adaptations that aid them in achieving stealth. First, the dull coloration of their feathers can render them almost invisible under certain conditions. Secondly, serrated edges on the leading edge of owls’ remiges muffle an owl’s wing beats, allowing an owl’s flight to be practically silent. Some fish-eating owls, for which silence has no evolutionary advantage, lack this adaptation

The systematic placement of owls is disputed. For example, the Sibley–Ahlquist taxonomy of birds finds that, based on DNA-DNA hybridization, owls are more closely related to the nightjars and their allies (Caprimulgiformes) than to the diurnal predators in the order Falconiformes; consequently, the Caprimulgiformes are placed in the Strigiformes, and the owls in general become a family, the Strigidae. A recent study indicates that the drastic rearrangement of the genome of the accipitrids may have obscured any close relationship of theirs with groups such as the owls. In any case, the relationships of the Caprimulgiformes, the owls, the falcons, and the accipitrid raptors are not resolved to satisfaction; currently, a trend to consider each group (with the possible exception of the accipitrids) as a distinct order is increasing.

Some 220 to 225 extant species of owls are known, subdivided into two families: 1. Typical owls or True owl family (Strigidae) and 2. barn-owls family (Tytonidae). Some entirely extinct families have also been erected based on fossil remains; these differ much from modern owls in being less specialized or specialized in a very different way (such as the terrestrial Sophiornithidae). The Paleocene genera Berruornis and Ogygoptynx show that owls were already present as a distinct lineage some 60–57 million years ago (Mya), hence, possibly also some 5 million years earlier, at the extinction of the nonavian dinosaurs. This makes them one of the oldest known groups of non-Galloanserae landbirds. The supposed “Cretaceous owls” Bradycneme and Heptasteornis are apparently nonavialan maniraptors.

During the Paleogene, the Strigiformes radiated into ecological niches now mostly filled by other groups of birds.^{[clarification needed]} The owls as known today, though, evolved their characteristic morphology and adaptations during that time, too. By the early Neogene, the other lineages had been displaced by other bird orders, leaving only barn-owls and typical owls. The latter at that time were usually a fairly generic type of (probably earless) owls similar to today’s North American spotted owl or the European tawny owl; the diversity in size and ecology found in typical owls today developed only subsequently.

Around the Paleogene-Neogene boundary (some 25 Mya), barn-owls were the dominant group of owls in southern Europe and adjacent Asia at least; the distribution of fossil and present-day owl lineages indicates that their decline is contemporary with the evolution of the different major lineages of typical owls, which for the most part seems to have taken place in Eurasia. In the Americas, rather an expansion of immigrant lineages of ancestral typical owls occurred.

The supposed fossil herons “Ardea” perplexa (Middle Miocene of Sansan, France) and “Ardea” lignitum (Late Pliocene of Germany) were more probably owls; the latter was apparently close to the modern genus Bubo. Judging from this, the Late Miocene remains from France described as “Ardea” aureliensis should also be restudied. The Messelasturidae, some of which were initially believed to be basal Strigiformes, are now generally accepted to be diurnal birds of prey showing some convergent evolution towards owls. The taxa often united under Strigogyps were formerly placed in part with the owls, specifically the Sophiornithidae; they appear to be Ameghinornithidae instead.

November 27, 2018

Tasmanian Devil

The Tasmanian devil (Sarcophilus harrisii) is a carnivorous marsupial of the family Dasyuridae. It was once native to mainland Australia and is now found in the wild only on the island state of Tasmania, including tiny east-coast Maria Island where there is a conservation project with disease-free animals.

The size of a small dog, the Tasmanian devil became the largest carnivorous marsupial in the world following the extinction of the thylacine in 1936. It is related to quolls and distantly related to the thylacine. It is characterised by its stocky and muscular build, black fur, pungent odour, extremely loud and disturbing screech, keen sense of smell, and ferocity when feeding. The Tasmanian devil’s large head and neck allow it to generate among the strongest bites per unit body mass of any extant mammal land predator, and it hunts prey and scavenges carrion as well as eating household products if humans are living nearby.

Although it is usually solitary, it sometimes eats with other devils and defecates in a communal location. Unlike most other dasyurids, the devil thermoregulates effectively and is active during the middle of the day without overheating. Despite its rotund appearance, the devil is capable of surprising speed and endurance, and can climb trees and swim across rivers.

It is believed that ancient marsupials migrated from what is now South America to Australia tens of millions of years ago during the time of Gondwana, and that they evolved as Australia became more arid. Fossils of species similar to modern devils have been found, but it is not known whether they were ancestors of the contemporary species, or whether the current devils co-existed with these species. The date that the Tasmanian devil became locally extinct from the Australian mainland is unclear; most evidence suggests they had contracted to three relict populations around 3000 years ago. A tooth found in Augusta, Western Australia has been dated to 430 years ago, but archaeologist Oliver Brown disputes this and considers the devil’s mainland extinction to have occurred around 3000 years ago.

This disappearance is usually blamed on dingoes, which are absent from Tasmania. Because they were seen as a threat to livestock and animals that humans hunted for fur in Tasmania, devils were hunted and became endangered. In 1941, the devils, which were originally seen as implacably vicious, became officially protected. Since then, scientists have contended that earlier concerns that the devils were the most significant threat to livestock were overestimated and misplaced.

Devils are not monogamous, and their reproductive process is very robust and competitive. Males fight one another for the females, and then guard their partners to prevent female infidelity. Females can ovulate three times in as many weeks during the mating season, and 80% of two-year-old females are seen to be pregnant during the annual mating season. Females average four breeding seasons in their life and give birth to 20–30 live young after three weeks’ gestation. The newborn are pink, lack fur, have indistinct facial features and weigh around 0.20 g (0.0071 oz) at birth. As there are only four nipples in the pouch, competition is fierce and few newborns survive. The young grow rapidly and are ejected from the pouch after around 100 days, weighing roughly 200 g (7.1 oz). The young become independent after around nine months, so the female spends most of her year in activities related to birth and rearing.

Since the late 1990s, the devil facial tumour disease (DFTD) has drastically reduced the devil population and now threatens the survival of the species, which in 2008 was declared to be endangered. Programs are currently being undertaken by the Government of Tasmania to reduce the impact of the disease, including an initiative to build up a group of healthy devils in captivity, isolated from the disease. While the thylacine was extant it preyed on the devil, which targeted young and unattended thylacine cubs in their dens. Localised populations of devils have also been severely reduced by collisions with motor vehicles, particularly when they are eating roadkill.

The devil is an iconic symbol of Tasmania and many organisations, groups and products associated with the state use the animal in their logos. It is seen as an important attractor of tourists to Tasmania and has come to worldwide attention through the Looney Tunes character of the same name. Starting in 2013, Tasmanian devils are again being sent to zoos around the world as part of the Australian government’s Save the Tasmanian Devil Program.

November 26, 2018

RUM

Rum display in a liquor store

Government House rum, manufactured by the Virgin Islands Company distillery in St. Croix, circa 1941

Rum is a distilled alcoholic drink made from sugarcane byproducts, such as molasses, or directly from sugarcane juice, by a process of fermentation and distillation. The distillate, a clear liquid, is then usually aged in oakbarrels.

The majority of the world’s rum production occurs in the Caribbean and Latin America. Rum is also produced in Australia, Portugal, Austria, Canada, Fiji, India, Japan, Mauritius, Nepal, New Zealand, the Philippines, Reunion Island, South Africa, Spain, Sweden, Taiwan, Thailand, the United Kingdom and the United States.

Rums are produced in various grades. Light rums are commonly used in cocktails, whereas “golden” and “dark” rums were typically consumed straight or neat, on the rocks, or used for cooking, but are now commonly consumed with mixers. Premium rums are also available, made to be consumed either straight or iced.

Rum plays a part in the culture of most islands of the West Indies as well as in The Maritimes and Newfoundland. This drink has famous associations with the Royal Navy (where it was mixed with water or beer to make grog) and piracy (where it was consumed as bumbo). Rum has also served as a popular medium of economic exchange, used to help fund enterprises such as slavery (see Triangular trade), organized crime, and military insurgencies (e.g., the American Revolution and Australia’s Rum Rebellion).

History

Origins

According to Maria Dembinska, the King of Cyprus, Peter I of Cyprus or Pierre I de Lusignan (9 October 1328 – 17 January 1369), brought rum with him as a gift for the other royal dignitaries at the Congress of Kraków, held in 1364.^[9] This is feasible given the position of Cyprus as a significant producer of sugar in the Middle Ages,^[10] although the alcoholic sugar drink named rum by Dembinska might not have resembled modern distilled rums very closely. Dembinska also suggests Cyprus rum was often drunk mixed with an almond milk drink, also produced in Cyprus, called soumada.^[11]

Another early rum-like drink is brum. Produced by the Malay people, brum dates back thousands of years.^[12] Marco Polo also recorded a 14th-century account of a “very good wine of sugar” that was offered to him in the area that became modern-day Iran.^[2]

The first distillation of rum in the Caribbean took place on the sugarcane plantations there in the 17th century. Plantation slaves discovered that molasses, a byproduct of the sugar refining process, could be fermented into alcohol.^[13] Later, distillation of these alcoholic byproducts concentrated the alcohol and removed impurities, producing the first modern rums. Tradition suggests this type of rum first originated on the island of Barbados. However, in the decade of the 1620s, rum production was also recorded in Brazil.^[14] A liquid identified as rum has been found in a tin bottle found on the Swedish warship Vasa, which sank in 1628.^[15]

A 1651 document from Barbados stated, “The chief fuddling they make in the island is Rumbullion, alias Kill-Divil, and this is made of sugar canes distilled, a hot, hellish, and terrible liquor.”^[13]

Colonial America[edit]

Pirates carrying rum to shore to purchase slaves as depicted in The Pirates Own Book by Charles Ellms

After rum’s development in the Caribbean, the drink’s popularity spread to Colonial North America. To support the demand for the drink, the first rum distillery in the British colonies of North America was set up in 1664 on Staten Island. Boston, Massachusetts had a distillery three years later.^[16] The manufacture of rum became early Colonial New England’s largest and most prosperous industry.^[17] New England became a distilling center due to the technical, metalworking and cooperage skills and abundant lumber; the rum produced there was lighter, more like whiskey. Rhode Island rum even joined gold as an accepted currency in Europe for a period of time.^[18]Estimates of rum consumption in the American colonies before the American Revolutionary War had every man, woman, or child drinking an average of 3 imperial gallons (14 l) of rum each year.^[19]

To support this demand for the molasses to produce rum, along with the increasing demand for sugar in Europe during the 17th and 18th centuries, a labor source to work the sugar plantations in the Caribbean was needed. A triangular trade in rum, molasses, and slaves was established between Africa, the Caribbean, and the colonies to support this need.^[20] The exchange was quite profitable, and the disruption to the trade caused by the Sugar Act in 1764 may have even helped cause the American Revolution.^[19] In the slave trade, rum was also used as a medium of exchange. For example, the slave Venture Smith, whose history was later published, had been purchased in Africa for four gallons of rum plus a piece of calico.

The popularity of rum continued after the American Revolution, with George Washington insisting on a barrel of Barbados rum at his 1789 inauguration.^[21]

Rum started to play an important role in the political system; candidates attempted to influence the outcome of an election through their generosity with rum. The people would attend the hustings to see which candidate appeared more generous. The candidate was expected to drink with the people to show he was independent and truly a republican.^[22]^[23]

Eventually the restrictions on sugar imports from the British islands of the Caribbean, combined with the development of American whiskey, led to a decline in the drink’s popularity in North America.

1235 N LOOP 336 WEST CONROE TX 77301

November 24, 2018

Squirrel

Image result for squirrels

Squirrels are members of the family Sciuridae, a family that includes small or medium-size rodents. The squirrel family includes tree squirrels, ground squirrels, chipmunks, marmots (including woodchucks), flying squirrels, and prairie dogs amongst other rodents. Squirrels are indigenous to the Americas, Eurasia, and Africa, and were introduced by humans to Australia. The earliest known squirrels date from the Eocene period and are most closely related to the mountain beaver and to the dormouse among other living rodent families.

Squirrels are generally small animals, ranging in size from the African pygmy squirrel at 7–10 cm (2.8–3.9 in) in length and just 10 g (0.35 oz) in weight, to the Laotian giant flying squirrel at 1.08 m (3 ft 7 in) in length and the Alpine marmot, which weighs from 5 to 8 kg (11 to 18 lb). Squirrels typically have slender bodies with bushy tails and large eyes. In general, their fur is soft and silky, though much thicker in some species than others. The coat color of squirrels is highly variable between—and often even within—species.

In most squirrel species, the hind limbs are longer than the fore limbs, while all species have either four or five toes on each paw. The paws, which include an often poorly developed thumb, have soft pads on the undersides and versatile, sturdy claws for grasping and climbing. Tree squirrels, unlike most mammals, can descend a tree head-first. They do so by rotating their ankles 180 degrees, enabling the hind paws to point backward and thus grip the tree bark from the opposite direction.

Squirrels live in almost every habitat, from tropical rainforest to semiarid desert, avoiding only the high polar regions and the driest of deserts. They are predominantly herbivorous, subsisting on seeds and nuts, but many will eat insects and even small vertebrates.

As their large eyes indicate, squirrels have an excellent sense of vision, which is especially important for the tree-dwelling species. Many also have a good sense of touch, with vibrissae on their limbs as well as their heads.

The teeth of sciurids follow the typical rodent pattern, with large incisors (for gnawing) that grow throughout life, and cheek teeth (for grinding) that are set back behind a wide gap, or diastema. The typical dental formula for sciurids is 1.0.1.31.0.1.3.

Many juvenile squirrels die in the first year of life. Adult squirrels can have a lifespan of 5 to 10 years in the wild. Some can survive 10 to 20 years in captivity. Premature death may be caused when a nest falls from the tree, in which case the mother may abandon her young if their body temperature is not correct. Many such baby squirrels have been rescued and fostered until they could be safely returned to the wild.

Squirrels mate either once or twice a year and, following a gestation period of three to six weeks, give birth to a number of offspring that varies by species. The young are altricial, being born naked, toothless, and blind. In most species of squirrel, the female alone looks after the young, which are weaned at six to ten weeks and become sexually mature by the end of their first year. In general, the ground-dwelling squirrel species are social, often living in well-developed colonies, while the tree-dwelling species are more solitary.

Ground squirrels and tree squirrels are usually either diurnal or crepuscular, while the flying squirrels tend to be nocturnal—except for lactating flying squirrels and their young, which have a period of diurnality during the summe

Because squirrels cannot digest cellulose, they must rely on foods rich in protein, carbohydrates, and fats. In temperate regions, early spring is the hardest time of year for squirrels because the nuts they buried are beginning to sprout (and thus are no longer available to eat), while many of the usual food sources have not yet become available. During these times, squirrels rely heavily on the buds of trees. Squirrels, being primarily herbivores, eat a wide variety of plants, as well as nuts, seeds, conifer cones, fruits, fungi, and green vegetation. Some squirrels, however, also consume meat, especially when faced with hunger. Squirrels have been known to eat small birds, young snakes, and smaller rodents, as well as bird eggs and insects. Indeed, some tropical squirrel species have shifted almost entirely to a diet of insects.

Predatory behavior has been observed in various species of ground squirrels, in particular the thirteen-lined ground squirrel. For example, Bailey, a scientist in the 1920s, observed a thirteen-lined ground squirrel preying upon a young chicken. Wistrand reported seeing this same species eating a freshly killed snake. Whitaker examined the stomachs of 139 thirteen-lined ground squirrels and found bird flesh in four of the specimens and the remains of a short-tailed shrew in one; Bradley, examining the stomachs of white-tailed antelope squirrels, found at least 10% of his 609 specimens’ stomachs contained some type of vertebrate, mostly lizards and rodents. Morgart observed a white-tailed antelope squirrel capturing and eating a silky pocket mouse.

The living squirrels are divided into five subfamilies, with about 58 genera and some 285 species. The oldest squirrel fossil, Hesperopetes, dates back to the Chadronian (late Eocene, about 40–35 million years ago) and is similar to modern flying squirrels.

A variety of fossil squirrels, from the latest Eocene to the Miocene, could not be assigned with certainty to any living lineage. At least some of these probably were variants of the oldest basal “protosquirrels” (in the sense that they lacked the full range of living squirrels’ autapomorphies). The distribution and diversity of such ancient and ancestral forms suggest the squirrels as a group may have originated in North America.

Apart from these sometimes little-known fossil forms, the phylogeny of the living squirrels is fairly straightforward. The three main lineages are the Ratufinae (Oriental giant squirrels), Sciurillinae and all other subfamilies. The Ratufinae contain a mere handful of living species in tropical Asia. The neotropical pygmy squirrel of tropical South America is the sole living member of the Sciurillinae. The third lineage, by far the largest, has a near-cosmopolitan distribution. This further supports the hypothesis that the common ancestor of all squirrels, living and fossil, lived in North America, as these three most ancient lineages seem to have radiated from there; if squirrels had originated in Eurasia, for example, one would expect quite ancient lineages in Africa, but African squirrels seem to be of more recent origin.

The main group of squirrels also can be split into three subgroups, which yield the remaining subfamilies. The Sciurinae contains the flying squirrels (Pteromyini) and the Sciurini, which among others contains the American tree squirrels; the former have often been considered a separate subfamily, but are now seen as a tribe of the Sciurinae. The pine squirrels (Tamiasciurus), on the other hand, are usually included with the main tree squirrel lineage, but appear to be about as distinct as the flying squirrels; hence, they are sometimes considered a distinct tribe, Tamiasciurini.

Two of the three subfamilies are of about equal size, containing between nearly 70 and 80 species each; the third is about twice as large. The Sciurinae contains arboreal (tree-living) squirrels, mainly of the Americas and to a lesser extent Eurasia. The Callosciurinae is most diverse in tropical Asia and contains squirrels that are also arboreal, but have a markedly different habitus and appear more “elegant”, an effect enhanced by their often very colorful fur. The Xerinae—the largest subfamily—are made up from the mainly terrestrial (ground-living) forms and include the large marmots and the popular prairie dogs, among others, as well as the tree squirrels of Africa; they tend to be more gregarious than other squirrels, which do not usually live together in close-knit groups.

November 23, 2018

Butterfly

Butterflies are insects in the macrolepidopteran clade Rhopalocera from the order Lepidoptera, which also includes moths. Adult butterflies have large, often brightly coloured wings, and conspicuous, fluttering flight. The group comprises the large superfamily Papilionoidea, which contains at least one former group, the skippers (formerly the superfamily “Hesperioidea”) and the most recent analyses suggest it also contains the moth-butterflies (formerly the superfamily “Hedyloidea”). Butterfly fossils date to the Paleocene, which was about 56 million years ago.

Butterflies have the typical four-stage insect life cycle. Winged adults lay eggs on the food plant on which their larvae, known as caterpillars, will feed. The caterpillars grow, sometimes very rapidly, and when fully developed, pupate in a chrysalis. When metamorphosis is complete, the pupal skin splits, the adult insect climbs out, and after its wings have expanded and dried, it flies off. Some butterflies, especially in the tropics, have several generations in a year, while others have a single generation, and a few in cold locations may take several years to pass through their entire life cycle.

Butterflies are often polymorphic, and many species make use of camouflage, mimicry and aposematism to evade their predators. Some, like the monarch and the painted lady, migrate over long distances. Many butterflies are attacked by parasites or parasitoids, including wasps, protozoans, flies, and other invertebrates, or are preyed upon by other organisms. Some species are pests because in their larval stages they can damage domestic crops or trees; other species are agents of pollination of some plants. Larvae of a few butterflies (e.g., harvesters) eat harmful insects, and a few are predators of ants, while others live as mutualists in association with ants. Culturally, butterflies are a popular motif in the visual and literary arts.

Butterflies feed primarily on nectar from flowers. Some also derive nourishment from pollen, tree sap, rotting fruit, dung, decaying flesh, and dissolved minerals in wet sand or dirt. Butterflies are important as pollinators for some species of plants. In general, they do not carry as much pollen load as bees, but they are capable of moving pollen over greater distances. Flower constancy has been observed for at least one species of butterfly.

Adult butterflies consume only liquids, ingested through the proboscis. They sip water from damp patches for hydration and feed on nectar from flowers, from which they obtain sugars for energy, and sodium and other minerals vital for reproduction. Several species of butterflies need more sodium than that provided by nectar and are attracted by sodium in salt; they sometimes land on people, attracted by the salt in human sweat. Some butterflies also visit dung, rotting fruit or carcasses to obtain minerals and nutrients. In many species, this mud-puddling behaviour is restricted to the males, and studies have suggested that the nutrients collected may be provided as a nuptial gift, along with the spermatophore, during mating.

In hilltopping, males of some species seek hilltops and ridge tops, which they patrol in search for females. Since it usually occurs in species with low population density, it is assumed these landscape points are used as meeting places to find mates.

Butterflies use their antennae to sense the air for wind and scents. The antennae come in various shapes and colours; the hesperiids have a pointed angle or hook to the antennae, while most other families show knobbed antennae. The antennae are richly covered with sensory organs known as sensillae. A butterfly’s sense of taste is coordinated by chemoreceptors on the tarsi, or feet, which work only on contact, and are used to determine whether an egg-laying insect’s offspring will be able to feed on a leaf before eggs are laid on it. Many butterflies use chemical signals, pheromones; some have specialized scent scales (androconia) or other structures (coremata or “hair pencils” in the Danaidae). Vision is well developed in butterflies and most species are sensitive to the ultraviolet spectrum. Many species show sexual dimorphism in the patterns of UV reflective patches. Colour vision may be widespread but has been demonstrated in only a few species. Some butterflies have organs of hearing and some species make stridulatory and clicking sounds.

Heteronympha merope taking off

Many species of butterfly maintain territories and actively chase other species or individuals that may stray into them. Some species will bask or perch on chosen perches. The flight styles of butterflies are often characteristic and some species have courtship flight displays. Butterflies can only fly when their temperature is above 27 °C (81 °F); when it is cool, they can position themselves to expose the underside of the wings to the sunlight to heat themselves up. If their body temperature reaches 40 °C (104 °F), they can orientate themselves with the folded wings edgewise to the sun. Basking is an activity which is more common in the cooler hours of the morning. Some species have evolved dark wingbases to help in gathering more heat and this is especially evident in alpine forms.

As in many other insects, the lift generated by butterflies is more than can be accounted for by steady-state, non-transitory aerodynamics. Studies using Vanessa atalanta in a wind tunnel show that they use a wide variety of aerodynamic mechanisms to generate force. These include wake capture, vortices at the wing edge, rotational mechanisms and the Weis-Fogh ‘clap-and-fling‘ mechanism. Butterflies are able to change from one mode to another rapidly.

Butterflies protect themselves from predators by a variety of means.

Giant swallowtail caterpillar everting its osmeterium in defence; it is also mimetic, resembling a bird dropping.

Chemical defences are widespread and are mostly based on chemicals of plant origin. In many cases the plants themselves evolved these toxic substances as protection against herbivores. Butterflies have evolved mechanisms to sequester these plant toxins and use them instead in their own defense. These defence mechanisms are effective only if they are well advertised; this has led to the evolution of bright colours in unpalatable butterflies (aposematism). This signal is commonly mimicked by other butterflies, usually only females. A Batesian mimic imitates another species to enjoy the protection of that species’ aposematism. The common Mormon of India has female morphs which imitate the unpalatable red-bodied swallowtails, the common rose and the crimson rose. Müllerian mimicry occurs when aposematic species evolve to resemble each other, presumably to reduce predator sampling rates; Heliconius butterflies from the Americas are a good example.

Eyespots of speckled wood (Pararge aegeria) distract predators from attacking the head. This insect can still fly with a damaged left hindwing.

Camouflage is found in many butterflies. Some like the oakleaf butterfly and autumn leaf are remarkable imitations of leaves. As caterpillars, many defend themselves by freezing and appearing like sticks or branches. Others have deimatic papilionid , such as rearing up and waving their front ends which are marked with eyespots as if they were snakes. Some papilionid caterpillars such as the giant swallowtail (Papilio cresphontes) resemble bird droppings so as to be passed over by predators. Some caterpillars have hairs and bristly structures that provide protection while others are gregarious and form dense aggregations. Some species are myrmecophiles, forming mutualistic associations with ants and gaining their protection. Behavioural defences include perching and angling the wings to reduce shadow and avoid being conspicuous. Some female Nymphalid butterflies guard their eggs from parasitoidal wasps.

The Lycaenidae have a false head consisting of eyespots and small tails (false antennae) to deflect attack from the more vital head region. These may also cause ambush predators such as spiders to approach from the wrong end, enabling the butterflies to detect attacks promptly. Many butterflies have eyespots on the wings; these too may deflect attacks, or may serve to attract mates.

Auditory defenses can also be used, which in the case of the Grizzled skipper refers to vibrations generated by the butterfly upon expanding its wings in an attempt to communicate with ant predators.

Many tropical butterflies have seasonal forms for dry and wet seasons. These are switched by the hormone ecdysone. The dry-season forms are usually more cryptic, perhaps offering better camouflage when vegetation is scarce. Dark colours in wet-season forms may help to absorb solar radiation.

Butterflies without defences such as toxins or mimicry protect themselves through a flight that is more bumpy and unpredictable than in other species. It is assumed this behavior makes it more difficult for predators to catch them, and is caused by the turbulence created by the small whirlpools formed by the wings during flight.

November 21, 2018

Dragonfly

A dragonfly is an insect belonging to the order Odonata, infraorder Anisoptera (from Greek ἄνισος anisos, “unequal” and πτερόν pteron, “wing”, because the hindwing is broader than the forewing). Adult dragonflies are characterized by large, multifaceted eyes, two pairs of strong, transparent wings, sometimes with coloured patches, and an elongated body. Dragonflies can be mistaken for the related group, damselflies (Zygoptera), which are similar in structure, though usually lighter in build; however, the wings of most dragonflies are held flat and away from the body, while damselflies hold the wings folded at rest, along or above the abdomen. Dragonflies are agile fliers, while damselflies have a weaker, fluttery flight. Many dragonflies have brilliant iridescent or metallic colours produced by structural coloration, making them conspicuous in flight. An adult dragonfly’s compound eyeshave nearly 24,000 ommatidia each.

Fossils of very large dragonfly ancestors in the Protodonata are found from 325 million years ago (Mya) in Upper Carboniferous rocks; these had wingspans up to about 750 mm (30 in). There are about 3,000 extant species. Most are tropical, with fewer species in temperate regions.

Dragonflies are predators, both in their aquatic larval stage, when they are known as nymphs or naiads, and as adults. Several years of their lives are spent as nymphs living in fresh water; the adults may be on the wing for just a few days or weeks. They are fast, agile fliers, sometimes migrating across oceans, and often live near water. They have a uniquely complex mode of reproduction involving indirect insemination, delayed fertilization, and sperm competition. During mating, the male grasps the female at the back of the head, and the female curls her abdomen under her body to pick up sperm from the male’s secondary genitalia at the front of his abdomen, forming the “heart” or “wheel” posture.

Loss of wetland habitat threatens dragonfly populations around the world. Dragonflies are represented in human culture on artifacts such as pottery, rock paintings, and Art Nouveau jewellery. They are used in traditional medicine in Japan and China, and caught for food in Indonesia. They are symbols of courage, strength, and happiness in Japan, but seen as sinister in European folklore. Their bright colours and agile flight are admired in the poetry of Alfred, Lord Tennyson and the prose of H. E. Bates.

Dragonflies and their relatives are an ancient group. The oldest fossils are of the Protodonata from the 325 Mya Upper Carboniferous of Europe, a group that included the largest insect that ever lived, Meganeuropsis permiana from the early Permian, with a wingspan around 750 mm (30 in); their fossil record ends with the Permian–Triassic extinction event (about 247 Mya). The Protanisoptera, another ancestral group which lacks certain wing vein characters found in modern Odonata, lived from the Early to Late Permian age until the end Permian event, and are known from fossil wings from current day United States, Russia, and Australia, suggesting they might have been cosmopolitan in distribution. The forerunners of modern Odonata are included in a clade called the Panodonata, which include the basal Zygoptera (damselflies) and the Anisoptera (true dragonflies) Today there are some 3000 species extant around the world.

Dragonflies (suborder Anisoptera) are heavy-bodied, strong-flying insects that hold their wings horizontally both in flight and at rest. By contrast, damselflies (suborder Zygoptera) have slender bodies and fly more weakly; most species fold their wings over the abdomen when stationary, and the eyes are well separated on the sides of the head.

An adult dragonfly has three distinct segments, the head, thorax, and abdomen as in all insects. It has a chitinous exoskeleton of hard plates held together with flexible membranes. The head is large with very short antennae. It is dominated by the two compound eyes, which cover most of its surface. The compound eyes are made up of ommatidia, the numbers being greater in the larger species. Aeshna interrupta has 22650 ommatidia of two varying sizes, 4500 being large. The facets facing downward tend to be smaller. Petalura gigantea has 23890 ommatidia of just one size. These facets provide complete vision in the frontal hemisphere of the dragonfly. The compound eyes meet at the top of the head (except in the Petaluridae and Gomphidae, as also in the genus Epiophlebia). Also, they have three simple eyes or ocelli. The mouthparts are adapted for biting with a toothed jaw; the flap-like labrum, at the front of the mouth, can be shot rapidly forward to catch prey. The head has a system for locking it in place that consists of muscles and small hairs on the back of the head that grip structures on the front of the first thoracic segment. This arrester system is unique to the Odonata, and is activated when feeding and during tandem flight.

Anatomy of a dragonfly

The thorax consists of three segments as in all insects. The prothorax is small and is flattened dorsally into a shield-like disc which has two transverse ridges. The mesothorax and metathorax are fused into a rigid, box-like structure with internal bracing, and provides a robust attachment for the powerful wing muscles inside it. The thorax bears two pairs of wings and three pairs of legs. The wings are long, veined, and membranous, narrower at the tip and wider at the base. The hindwings are broader than the forewings and the venation is different at the base. The veins carry haemolymph, which is analogous to blood in vertebrates and carries out many similar functions, but which also serves a hydraulic function to expand the body between nymphal stages (instars) and to expand and stiffen the wings after the adult emerges from the final nymphal stage. The leading edge of each wing has a node where other veins join the marginal vein, and the wing is able to flex at this point. In most large species of dragonflies, the wings of females are shorter and broader than those of males. The legs are rarely used for walking, but are used to catch and hold prey, for perching, and for climbing on plants. Each has two short basal joints, two long joints, and a three-jointed foot, armed with a pair of claws. The long leg joints bear rows of spines, and in males, one row of spines on each front leg is modified to form an “eyebrush”, for cleaning the surface of the compound eye.

Migrant hawker, Aeshna mixta, has the long slender abdomen of aeshnid dragonflies.

The abdomen is long and slender and consists of 10 segments. There are three terminal appendages on segment 10; a pair of superiors (claspers) and an inferior. The second and third segments are enlarged, and in males, on the underside of the second segment has a cleft, forming the secondary genitalia consist of lamina, hamule, genital lobe and penis. There is remarkable variations in the presence and the form of the penis and the related structures, the flagellum, cornua and genital lobes. Sperm is produced at the 9th segment and is transferred to the secondary genitalia prior to mating. The male holds the female behind the head using a pair of claspers on the terminal segment. In females, the genital opening is on the underside of the eighth segment and is covered by a simple flap (vulvar lamina) or an ovipositor, depending on species and the method of egg-laying. Dragonflies having simple flap shed the eggs in water, mostly in flight. Dragonflies having ovipositor, use it to puncture soft tissues of plants and place the eggs singly in each puncture they made.

Dragonfly nymphs vary in form with species and are loosely classed into claspers, sprawlers, hiders, and burrowers. The first instar is known as a prolarva, a relatively inactive stage from which it quickly moults into the more active nymphal form. The general body plan is similar to that of an adult, but the nymph lacks wings and reproductive organs. The lower jaw has a huge, extensible labium, armed with hooks and spines, which is used for catching prey. This labium is folded under the body at rest and struck out at great speed by hydraulic pressure created by the abdominal muscles. Whereas damselfly nymphs have three feathery external gills, dragonfly nymphs have internal gills, located around the fourth and fifth abdominal segments. Water is pumped in and out of the abdomen through an opening at the tip. The naiads of some clubtails (Gomphidae) that burrow into the sediment, have a snorkel-like tube at the end of the abdomen enabling them to draw in clean water while they are buried in mud. Naiads can forcefully expel a jet of water to propel themselves with great rapidity.

Many adult dragonflies have brilliant iridescent or metallic colours produced by structural coloration, making them conspicuous in flight. Their overall coloration is often a combination of yellow, red, brown, and black pigments, with structural colours. Blues are typically created by microstructures in the cuticle that reflect blue light. Greens often combine a structural blue with a yellow pigment. Freshly emerged adults, known as tenerals, are often pale-coloured and obtain their typical colours after a few days, some have their bodies covered with a pale blue, waxy powderiness called pruinosity; it wears off when scraped during mating, leaving darker areas.

Noniridescent structural blue occurs in the green darner, Anax junius; the female (below) lacks blue.

Some dragonflies, such as the green darner, Anax junius, have a noniridescent blue which is produced structurally by scatter from arrays of tiny spheres in the endoplasmic reticulum of epidermal cells underneath the cuticle.

The wings of dragonflies are generally clear, apart from the dark veins and pterostigmata. In the chasers (Libellulidae), however, many genera have areas of colour on the wings: for example, groundlings (Brachythemis) have brown bands on all four wings, while some scarlets (Crocothemis) and dropwings (Trithemis) have bright orange patches at the wing bases. Some aeshnids such as the brown hawker (Aeshna grandis) have translucent, pale yellow wings.

Dragonfly nymphs are usually a well-camouflaged blend of dull brown, green, and grey.

Dragonflies are hemimetabolous insects; they do not have a pupal stage and undergo an incomplete metamorphosis with a series of nymphal stages from which the adult emerges. Eggs laid inside plant tissues are usually shaped like grains of rice, while other eggs are the size of a pinhead, ellipsoidal, or nearly spherical. A clutch may have as many as 1500 eggs, and they take about a week to hatch into aquatic nymphs or naiads which moult between six and 15 times (depending on species) as they grow. Most of a dragonfly’s life is spent as a nymph, beneath the water’s surface. The nymph extends its hinged labium (a toothed mouthpart similar to a lower mandible, which is sometimes termed as a “mask” as it is normally folded and held before the face) that can extend forward and retract rapidly to capture prey such as mosquito larvae, tadpoles, and small fish. They breathe through gills in their rectum, and can rapidly propel themselves by suddenly expelling water through the anus. Some naiads, such as the later stages of Antipodophlebia asthenes, hunt on land.

Ecdysis: Emperor dragonfly, Anax imperator, newly emerged and still soft, holding on to its dry exuvia, and expanding its wings

Parts of a dragonfly nymph including the labial “mask”

The larval stage of dragonflies lasts up to five years in large species, and between two months and three years in smaller species. When the naiad is ready to metamorphose into an adult, it stops feeding and makes its way to the surface, generally at night. It remains stationary with its head out of the water, while its respiration system adapts to breathing air, then climbs up a reedor other emergent plant, and moults (ecdysis). Anchoring itself firmly in a vertical position with its claws, its skin begins to split at a weak spot behind the head. The adult dragonfly crawls out of its larval skin, the exuvia, arching backwards when all but the tip of its abdomen is free, to allow its exoskeleton to harden. Curling back upwards, it completes its emergence, swallowing air, which plumps out its body, and pumping haemolymph into its wings, which causes them to expand to their full extent.

Dragonflies in temperate areas can be categorized into two groups, an early group and a later one. In any one area, individuals of a particular “spring species” emerge within a few days of each other. The springtime darner (Basiaeschna janata), for example, is suddenly very common in the spring, but disappears a few weeks later and is not seen again until the following year. By contrast, a “summer species” emerges over a period of weeks or months, later in the year. They may be seen on the wing for several months, but this may represent a whole series of individuals, with new adults hatching out as earlier ones complete their short lifespans which is an average of 7 months.

Dragonflies are powerful and agile fliers, capable of migrating across the sea, moving in any direction, and changing direction suddenly. In flight, the adult dragonfly can propel itself in six directions: upward, downward, forward, backward, to left and to right. They have four different styles of flight: A number of flying modes are used that include counter-stroking, with forewings beating 180° out of phase with the hindwings, is used for hovering and slow flight. This style is efficient and generates a large amount of lift; phased-stroking, with the hindwings beating 90° ahead of the forewings, is used for fast flight. This style creates more thrust, but less lift than counter-stroking; synchronised-stroking, with forewings and hindwings beating together, is used when changing direction rapidly, as it maximises thrust; and gliding, with the wings held out, is used in three situations: free gliding, for a few seconds in between bursts of powered flight; gliding in the updraft at the crest of a hill, effectively hovering by falling at the same speed as the updraft; and in certain dragonflies such as darters, when “in cop” with a male, the female sometimes simply glides while the male pulls the pair along by beating his wings.

Southern hawker, Aeshna cyanea: its wings at this instant are synchronised for agile flight.

The wings are powered directly, unlike most families of insects, with the flight muscles attached to the wing bases. Dragonflies have a high power/weight ratio, and have been documented accelerating at 4 G linearly and 9 G in sharp turns while pursuing prey.

Dragonflies generate lift in at least four ways at different times, including classical lift like an aircraft wing; supercritical lift with the wing above the critical angle, generating high lift and using very short strokes to avoid stalling; and creating and shedding vortices. Some families appear to use special mechanisms, as for example the Libellulidae which take off rapidly, their wings beginning pointed far forward and twisted almost vertically. Dragonfly wings behave highly dynamically during flight, flexing and twisting during each beat. Among the variables are wing curvature, length and speed of stroke, angle of attack, forward/back position of wing, and phase relative to the other wings.

Old and unreliable claims are made that dragonflies such as the southern giant darner can fly up to 97 km/h (60 mph). However, the greatest reliable flight speed records are for other types of insects. In general, large dragonflies like the hawkers have a maximum speed of 36–54 km/h (22–34 mph) with average cruising speed of about 16 km/h (9.9 mph). Dragonflies can travel at 100 body-lengths per second in forward flight, and three lengths per second backwards

In high-speed territorial battles between male Australian emperors (Hemianax papuensis), the fighting dragonflies adjust their flight paths to appear stationary to their rivals, minimizing the chance of being detected as they approach. To achieve the effect, the attacking dragonfly flies towards his rival, choosing his path to remain on a line between the rival and the start of his attack path. The attacker thus looms larger as he closes on the rival, but does not otherwise appear to move. Researchers found that six of 15 encounters involved motion camouflage.

November 20, 2018

American bullfrog

The American bullfrog (Lithobates catesbeianus or Rana catesbeiana), often simply known as the bullfrog in Canada and the United States, is an amphibious frog, a member of the family Ranidae, or “true frogs”. This frog has an olive green back and sides blotched with brownish markings and a whitish belly spotted with yellow or grey. The upper lip is often bright green and males have yellow throats. It inhabits large, permanent water bodies, such as swamps, ponds, and lakes, where it is usually found along the water’s edge. The male bullfrog defends a territory during the breeding season. His call is reminiscent of the roar of a bull, which gives the frog its common name. This frog is native to southern and eastern parts of the United States and Canada, but has been widely introduced across other parts of North, Central and South America, Western Europe, and parts of Asia, and in some areas is regarded as an invasive species.

The bullfrog is harvested for use as food in North America and in several countries into which it has been introduced. It is also cultured in controlled environments, though this is a difficult and not always successful undertaking. Some international trade in frog legs occurs for human consumption. Bullfrogs are used in biology classes in schools for dissection and are sometimes kept as pets.

The dorsal (upper) surface of the bullfrog has an olive-green basal color, either plain or with a mottling and banding of grayish brown. The ventral (under) surface is off-white blotched with yellow or gray. Often, a marked contrast in color is seen between the green upper lip and the pale lower lip. The teeth are tiny and are useful only in grasping. The eyes are prominent with brown irises and horizontal, almond-shaped pupils. The tympana (eardrums) are easily seen just behind the eyes and the dorsolateral folds of skin end close to them. The limbs are blotched or banded with gray. The fore legs are short and sturdy and the hind legs long. The front toes are not webbed, but the back toes have webbing between the digits with the exception of the fourth toe, which is unwebbed.

Bullfrogs are sexually dimorphic, with males being smaller than females and having yellow throats. Males have tympana larger than their eyes, whereas the tympana in females are about the same size as the eyes. Bullfrogs measure about 3.6 to 6 in (9 to 15 cm) from snout to vent. They grow fast in the first eight months of life, typically increasing in weight from 5 to 175 g (0.18 to 6.17 oz), and large, mature individuals can weigh up to 500 g (1.1 lb). In some cases bullfrogs have been recorded as attaining 800 g (1.8 lb) and measuring up to 8 in (20 cm) in length.

After selecting a male, the female deposits eggs in his territory. During the mating grasp, or amplexus, the male rides on top of the female, grasping her just behind her fore limbs. The female chooses a site in shallow water among vegetation, and lays a batch of up to 20,000 eggs, and the male simultaneously releases sperm, resulting in external fertilization. The eggs form a thin, floating sheet which may cover an area of 0.5 to 1.0 m² (5.4 to 10.8 sq ft). The embryos develop best at water temperatures between 24 and 30 °C (75 and 86 °F) and hatch in three to five days. If the water temperature rises above 32 °C (90 °F), developmental abnormalities occur, and if it falls below 15 °C (59 °F), normal development ceases. Newly hatched tadpoles show a preference for living in shallow water on fine gravel bottoms. This may reflect a lesser number of predators in these locations. As they grow, they tend to move into deeper water. The tadpoles initially have three pairs of external gills and several rows of labial teeth. They pump water through their gills by movements of the floor of their mouths, trapping bacteria, single-celled algae, protozoans, pollen grains, and other small particles on mucus in a filtration organ in their pharynges. As they grow, they begin to ingest larger particles and use their teeth for rasping. They have downward-facing mouths, deep bodies, and tails with broad dorsal and ventral fins.

Time to metamorphosis ranges from a few months in the southern part of the range to 3 years in the north, where the colder water slows development. Maximum lifespan in the wild is estimated to be 8 to 10 years, but one frog lived for almost 16 years in captivity.

The American bullfrog provides a food source, especially in the Southern and some areas of the Midwestern United States. The traditional way of hunting them is to paddle or pole silently by canoe or flatboat in ponds or swamps at night; when the frog’s call is heard, a light is shone at the frog which temporarily inhibits its movement. The frog will not jump into deeper water as long as it is approached slowly and steadily. When close enough, the frog is gigged with a multiple-tined spear and brought into the boat. Bullfrogs can also be stalked on land, by again taking great care not to startle them. In some states, breaking the skin while catching them is illegal, and either grasping gigs or hand captures are used. The only parts normally eaten are the rear legs, which resemble small chicken drumsticks and can be cooked in similar ways.

American bullfrog caught at night by a pond in the Southern United States on a homemade frog gig

Commercial bullfrog culture in near-natural enclosed ponds has been attempted, but is fraught with difficulties. Although pelleted feed is available, the frogs will not willingly consume artificial diets, and providing sufficient live prey is challenging. Disease also tends to be a problem even when great care is taken to provide sanitary conditions. Other challenges to be overcome may be predation, cannibalism, and low water quality.^[48] The frogs are large, have powerful leaps, and inevitably escape after which they may wreak havoc among the native frog population. Countries that export bullfrog legs include the Netherlands, Belgium, Mexico, Bangladesh, Japan, China, Taiwan, and Indonesia. Most of these frogs are caught from the wild, but some are captive-reared. The United States is a net importer of frog legs.

The American bullfrog is used as a specimen for dissection in many schools across the world. It is the state amphibian of Missouri, Ohio, and Oklahoma.

November 19, 2018

ATOLE

Atole or Spanish a’tole (help·info), from Nahuatl ātōlli [aːˈtoːlːi]), also known as atol and atol de elote, is a traditional hot corn- and masa-based beverage of Mesoamerican origin. Chocolate atole is known as champurrado or atole. It is typically accompanied with tamales, and very popular during the Christmas holiday season (las Posadas)

In Mexico[edit]

In Mexico, the drink typically includes masa (corn hominy flour), water, piloncillo (unrefined cane sugar), cinnamon, vanilla, and optional chocolate or fruit. The mixture is blended and heated before serving. Atole is made by toasting masa on a comal (griddle), then adding water that was boiled with cinnamon sticks. The resulting blends vary in texture, ranging from a porridge to a very thin, liquid consistency. Atole can also be prepared with rice, flour, or oatmeal in place of masa. In northern Mexico, a variation is also made using pinole (sweetened toasted corn meal). Although atole is one of the traditional drinks of the Mexican holiday Day of the Dead, it is very common during breakfast and dinnertime at any time of year. It is usually sold as street food.

Atole served at the Atole Fair in Coacalco de Berriozábal, State of Mexico

In Northern Mexico and South Texas, atole is a traditional comfort food. It is often eaten as a breakfast or an after dinner snack on cold days. In New Mexico, blue corn atole is finely ground cornmeal toasted for cooking, consumed as a grainy porridge-style drink served warm, usually sweetened with sugar and/or thinned with milk. It is usually served at breakfast like cream of wheat or oatmeal. Elders are said to have drunk atole because it gave them energy and if a mother is nursing it gives her more milk.^[1] Salvadoran varieties include atol shuco (“dirty” atol, a reference to its darker color), particularly popular in the Cabañas region.^[2] The Nicaraguanhomologue is pinolillo. In some parts of Honduras, fresh corn is ground and the expressed liquid is used as the base (instead of masa

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