Saturday, September 20, 2008

SNAKE


A snake is an elongate reptile of the suborder Serpentes. Like all reptiles, snakes are covered in scales. All snakes are carnivorous and can be distinguished from legless lizards by their lack of eyelids, limbs, external ears, and vestiges of forelimbs. The 2,700+ species of snakes spread across every continent except Antarctica ranging in size from the tiny, 10 cm long thread snake to pythons and anacondas at 9 m (30 ft) long. In order to accommodate snakes' narrow bodies, paired organs (such as kidneys) appear one in front of the other instead of side by side.

While venomous snakes comprise a minority of the species, some possess potent venom capable of causing painful injury or death to humans. However, venom in snakes is primarily for killing and subduing prey rather than for self-defense. Snakes may have evolved from a lizard which adapted to burrowing during the Cretaceous period (c 150 Ma), though some scientists have postulated an aquatic origin. The diversity of modern snakes appeared during the Paleocene period (c 66 to 56 Ma).

A literary word for snake is serpent (a Middle English word which comes from Old French, and ultimately from *serp-, "to creep"[1], also ερπω in Greek). The serpent is also a symbol of the healing arts.

All snakes are strictly carnivorous, eating small animals including lizards, other snakes, small mammals, birds, eggs, fish, snails or insects.[2][3][4] Because snakes cannot bite or tear their food to pieces, a snake must swallow its prey whole. The body size of a snake has a major influence on its eating habits. Smaller snakes eat smaller prey. Juvenile pythons might start out feeding on lizards or mice and graduate to small deer or antelope as an adult, for example.

The snake's jaw is the most unique jaw in the animal kingdom. Contrary to the popular belief that snakes can dislocate their jaws, snakes have a very flexible lower jaw, the two halves of which are not rigidly attached, and numerous other joints in their skull (see snake skull), allowing them to open their mouths wide enough to swallow their prey whole, even if it is larger in diameter than the snake itself,[3] as snakes do not chew. For example, the African Egg-eating Snake has flexible jaws adapted for eating eggs much larger than the diameter of its head.[4] This snake has no teeth, but does have bony protrusions on the inside edge of its spine which are used to aid in breaking the shells of the eggs it eats.[4]

While the majority of snakes eat a variety of prey animals, there is some specialization by some species. King cobras and the Australian Bandy-bandy consume other snakes. Pareas iwesakii and other snail-eating Colubrids of subfamily Pareatinae have more teeth on the right side of their mouths than on the left, as the shells of their prey usually spiral clockwise[5][6]

Some snakes have a venomous bite, which they use to kill their prey before eating it.[7][3] Other snakes kill their prey by constriction.[3] Still others swallow their prey whole and alive.[3][4]


African Egg-eating snakeAfter eating, snakes become dormant while the process of digestion takes place.[8] Digestion is an intense activity, especially after consumption of very large prey. In species that feed only sporadically, the entire intestine enters a reduced state between meals to conserve energy, and the digestive system is 'up-regulated' to full capacity within 48 hours of prey consumption. Being cold-blooded (ectothermic), the surrounding temperature plays a large role in a snake's digestion. 30 degrees Celsius is the ideal temperature for snakes to digest their food. So much metabolic energy is involved in a snake's digestion that in Crotalus durissus, the Mexican rattlesnake, an increase of body temperature to as much as 1.2 degrees Celsius above the surrounding environment has been observed.[9] Because of this, a snake disturbed after having eaten recently will often regurgitate its prey in order to be able to escape the perceived threat. When undisturbed, the digestive process is highly efficient, with the snake's digestive enzymes dissolving and absorbing everything but the prey's hair and claws, which are excreted along with waste.

The skin of a snake is covered in scales. Contrary to the popular notion of snakes being slimy because of possible confusion of snakes with worms, snakeskin has a smooth, dry texture. Most snakes use specialized belly scales to travel, gripping surfaces. The body scales may be smooth, keeled, or granular. Snake's eyelids are transparent "spectacle" scales which remain permanently closed, also known as brille.

The shedding of scales is called ecdysis, or, in normal usage moulting or sloughing. In the case of snakes, the complete outer layer of skin is shed in one layer.[22] Snake scales are not discrete but extensions of the epidermis hence they are not shed separately, but are ejected as a complete contiguous outer layer of skin during each moult, akin to a sock being turned inside out.[23]


A line diagram from G.A. Boulenger's Fauna of British India (1890) illustrating the terminology of shields on the head of a snakeMoulting serves a number of functions – firstly, the old and worn skin is replaced, secondly, it helps get rid of parasites such as mites and ticks. Renewal of the skin by moulting is supposed to allow growth in some animals such as insects, however this view has been disputed in the case of snakes.[23][24]


A snake shedding its skinMoulting is repeated periodically throughout a snake's life. Before a moult, the snake stops eating and often hides or moves to a safe place. Just before shedding, the skin becomes dull and dry looking and the eyes become cloudy or blue-colored. The inner surface of the old outer skin liquefies. This causes the old outer skin to separate from the new inner skin. After a few days, the eyes clear and the snake "crawls" out of its old skin. The old skin breaks near the mouth and the snake wriggles out aided by rubbing against rough surfaces. In many cases the cast skin peels backward over the body from head to tail, in one piece like an old sock. A new, larger, and brighter layer of skin has formed underneath.[23][25]

An older snake may shed its skin only once or twice a year, but a younger, still-growing snake, may shed up to four times a year.[25] The discarded skin gives a perfect imprint of the scale pattern and it is usually possible to identify the snake if this discard is reasonably complete and intact.[23] This periodic renewal has led to the snake being a symbol of healing and medicine, as pictured in the Rod of Asclepius.[26]

The shape and number of scales on the head, back and belly are characteristic to family, genus and species. Scales have a nomenclature analogous to the position on the body. In "advanced" (Caenophidian) snakes, the broad belly scales and rows of dorsal scales correspond to the vertebrae, allowing scientists to count the vertebrae without dissection.

Scalation counts are also used to tell the sex of a snake when the species is not readily sexually dimorphic. A probe is inserted into the cloaca until it can go no further. The probe is marked at the point where it stops, removed, and compared to the subcaudal depth by laying it alongside the scales.[8] The scalation count determines whether the snake is a male or female as hemipenes of a male will probe to a different depth (usually longer) than the cloaca of a female.

DONKEY


The donkey or ass, Equus asinus, is a member of the Equidae or horse family, and an odd-toed ungulate. The words donkey and ass are applied to the domesticated E. asinus. The animal considered to be its wild ancestor is the African Wild Ass, also E. asinus.
Colloquially, the term "ass" is often used today to refer to a larger, horse-sized animal, and "donkey" to a smaller, pony-sized one. In the western United States, a small donkey is sometimes called a burro. A male donkey or ass is called a jack, a female a jenny, and offspring less than one year old, a foal (male: colt, female filly).
While different species of the Equidae family can interbreed, offspring are almost always sterile. Nonetheless, horse/donkey hybrids are popular for their durability and vigor. A mule is the offspring of a jack (male) donkey and a mare (female horse). The much rarer successful mating of a male horse and a female donkey produces a hinny.
Asses were first domesticated around 3000 BCE[1], approximately the same time as the horse, and have spread around the world. They continue to fill important roles in many places today and domesticated species are increasing in numbers (although the African wild ass and another relative, the Onager, are endangered species). As "beasts of burden" and companions, asses and donkeys have worked together with humans for centuries
Donkeys vary considerably in size, depending on breed and management. Most domestic donkeys range from 0.9 to over 1.4 m tall, though the Mammoth Jack breed is taller, and the Andalucian-Cordobesan breed of southern Spain can reach up to 1.6 m high.
Donkeys are adapted to marginal desert lands, and have many traits that are unique to the species as a result. Wild donkeys live separated from each other, unlike tight wild horse and feral horse herds. Donkeys have developed very loud vocalizations, which help keep in contact with other donkeys over the wide spaces of the desert. The best-known call is referred to a "bray," which can be heard for over three kilometers. Donkeys have larger ears than horses. Their longer ears may pick up more distant sounds,[citation needed] and may help cool the donkey's blood. Donkeys in the wild can defend themselves with a powerful kick of their hind legs as well as by biting and striking with their front feet.
Donkeys' tough digestive system is somewhat less prone to colic than that of horses, can break down near-inedible vegetation and extract moisture from food very efficiently. As a rule, donkeys need smaller amounts of feed than horses of comparable height and weight. Because they are easy keepers, if overfed, donkeys are also quite susceptible to developing a condition called laminitis
A male donkey (jack) can be crossed with a female horse to produce a mule. A male horse can be crossed with a female donkey (jennet or jenny) to produce a hinny. A female donkey in the UK is called a mare, or jenny.
Horse-donkey hybrids are almost always sterile because horses have 64 chromosomes whereas donkeys have 62, producing offspring with 63 chromosomes. Mules are much more common than hinnies. This is believed to be caused by two factors, the first being proven in cat hybrids, that when the chromosome count of the male is the higher, fertility rates drop (as in the case of stallion x jennet).[citation needed] The lower progesterone production of the jenny may also lead to early embryonic loss. In addition, there are less-scientific reasons: Due to different mating behavior, jacks are often more willing to cover mares than stallions are to breed jennys. Further, mares are usually larger than jennys and thus have more room for the ensuing foal to grow in the womb, resulting in a larger animal at birth. It is commonly believed that mules are more easily handled and also physically stronger than hinnies, making them more desirable for breeders to produce, and it is unquestioned that mules are more common in total number.
The offspring of a zebra-donkey cross is called a zonkey, zebroid, zebrass, or zedonk;[13] zebra mule is an older term, but still used in some regions today. The foregoing terms generally refer to hybrids produced by breeding a male zebra to a female donkey. Zebra hinny, zebret and zebrinny all refer to the cross of a female zebra with a male donkey. Zebrinnies are rarer than zedonkies because female zebras in captivity are most valuable when used to produce full-blooded zebras.[14] There are not enough female zebras breeding in captivity to spare them for hybridizing; there is no such limitation on the number of female donkeys breeding.
For at least the past century, a few donkeys and burros in Mexico have been painted with white stripes to amuse tourists. These are not hybrids.
An animal which may look like a zebra-donkey hybrid because of its distinctly striped hindquarters and hind legs is the okapi, which has no relationship to either of those species. Okapi are most closely related to the giraffe. In addition to the rear stripes, okapi have some striping near the top of their forelegs

RABBIT


Rabbits are clearly distinguished from hares in that rabbits are altricial, having young that are born blind and hairless. In contrast, hares are generally born with hair and are able to see (precocial). All rabbits except the cottontail rabbit live underground in burrows or warrens, while hares live in simple nests above the ground (as does the cottontail rabbit), and usually do not live in groups. Hares are generally larger than rabbits, with longer ears, and have black markings on their fur. Hares have not been domesticated, while rabbits are often kept as house pets. In gardens, they are typically kept in hutches—
small, wooden, house-like boxes—that protect the rabbits from the environment and predators
Pet rabbits kept indoors are referred to as house rabbits. House rabbits typically have an indoor pen or cage and a rabbit-safe place to run and exercise, such as an exercise pen, living room or family room. Rabbits can be trained to use a litter box and some can learn to come when called. Domestic rabbits that do not live indoors can also often serve as companions for their owners, typically living in an easily accessible hutch outside the home. Some pet rabbits live in outside hutches during the day for the benefit of fresh air and natural daylight and are brought inside at night.
Whether indoor or outdoor, pet rabbits' pens are often equipped with enrichment activities such as shelves, tunnels, balls, and other toys. Pet rabbits are often provided additional space in which to get exercise, simulating the open space a rabbit would traverse in the wild. Exercise pens or lawn pens are often used to provide a safe place for rabbits to run.
A pet rabbit's diet typically consists of unlimited Timothy hay, a small amount of pellets, and a small portion of fresh vegetables.
Rabbits are social animals. Rabbits as pets can find their companionship with a variety of creatures, including humans, other rabbits, guinea pigs, and sometimes even cats and dogs. Rabbits do not make good pets for small children because they do not know how to stay quiet, calm, and gentle around rabbits. As prey animals, rabbits are alert, timid creatures that startle easily. They have fragile bones, especially in their backs, that require support on the belly and bottom when picked up. Children 10 years old and older usually have the maturity required to care for a rabbit.
The long ears of rabbits are most likely an adaptation for detecting predators. In addition to their prominent ears, which can measure more than 10 cm (4 in) long, rabbits have long, powerful hind legs and a short tail. Each foot has five digits (one reduced); rabbits move about on the tips of the digits in a fashion known as digitigrade locomotion. Full-bodied and egg-shaped, wild rabbits are rather uniform in body proportions and stance. The smallest is the pygmy rabbit (Brachylagus idahoensis), at only 20 cm in length and 0.4 kg (0.9 pound) in weight, while the largest grow to 50 cm and more than 2 kg. The fur is generally long and soft, and its color ranges through shades of brown, gray, and buff. Exceptions are the black Amami rabbit (Pentalagus furnessi) of Japan and two black-striped species from Southeast Asia. The tail is usually a small puff of fur, generally brownish but white on top in the cottontails (genus Sylvilagus) of North and South America
Rabbits are ground dwellers that live in environments ranging from desert to tropical forest and wetland. Their natural geographic range encompasses the middle latitudes of the Western Hemisphere. In the Eastern Hemisphere rabbits are found in Europe, portions of Central and Southern Africa, the Indian subcontinent, Sumatra, and Japan. The European rabbit (Oryctolagus cuniculus) has been introduced to many locations around the world, and all breeds of domestic rabbit originate from the European

RHINOCEROUS


Rhinoceros , often colloquially abbreviated rhino, is the common name used to group five extant species of odd-toed ungulates in the family Rhinocerotidae. Two of these species are native to Africa and three to southern Asia. Three of the five species—the (Javan, Sumatran and Black Rhinoceros)—are critically endangered. The Indian is endangered, with fewer than 2700 individuals remaining in the wild. The White is registered as Vulnerable, with roughly 14,500 remaining in the wild.[citation needed]

The White Rhino has a massive body and large head, a short neck and broad chest. This rhino can exceed 3000 kg (6600 pounds), have a head-and-body length of 3.35-4.2 m (11-13.9 feet) and a shoulder height of 150-185 cm (60-73 inches). The record-sized White Rhinoceros was about 4500 kg (10,000 lb).[1]. On its snout it has two horns. The front horn is larger than the other horn and averages 89.9 cm (23.6 inches) in length and can reach 150 cm (59 inches). The White Rhinoceros also has a noticeable hump on the back of its neck which supports its large head. The colour of this animal ranges from yellowish brown to slate grey. The only hair on them is on the ear fringes and tail bristles with little across the body. White Rhinos have the distinctive flat broad mouth which is used for grazing.

The name Black Rhinoceros (Diceros bicornis) was chosen to distinguish this species from the White Rhinoceros (Ceratotherium simum). This can be confusing, as those two species are not really distinguishable by colour. There are four subspecies of black rhino: South-central (Diceros bicornis minor), the most numerous, which once ranged from central Tanzania south through Zambia, Zimbabwe and Mozambique to northern and eastern South Africa; South-western (Diceros bicornis bicornis) which are better adapted to the arid and semi-arid savannas of Namibia, southern Angola, western Botswana and western South Africa; East African (Diceros bicornis michaeli), primarily in Tanzania; and West African (Diceros bicornis longipes) which was tentatively declared extinct in 2006.[2]

An adult Black Rhinoceros stands 147–160 cm (57.9–63 inches) high at the shoulder and is 3.3-3.6 m (10.8–11.8 feet) in length.[3] An adult weighs from 800 to 1400 kg (1,760 to 3,080 lb), exceptionally to 1820 kg (4,000 lb), with the females being smaller than the males. Two horns on the skull are made of keratin with the larger front horn typically 50 cm long, exceptionally up to 140 cm. Sometimes, a third smaller horn may develop. The Black Rhino is much smaller than the White Rhino, and has a pointed mouth, which they use to grasp leaves and twigs when feeding.

The Indian Rhinoceros or the Great One-horned Rhinoceros (Rhinoceros unicornis) is found in Nepal and in Assam, India. It is also known as Gaida in Nepali. The rhino once inhabited areas from Pakistan to Burma and may have even roamed in China. But because of human influence their range has shrunk and now they only exist in small populations in north-eastern India and Nepal. It is confined to the tall grasslands and forests in the foothills of the Himalayas.

The Indian Rhinoceros has thick, silver-brown skin which creates huge folds all over its body. Its upper legs and shoulders are covered in wart-like bumps, and it has very little body hair. Fully grown males are larger than females in the wild, weighing from 2200–3000 kg (4,800–6,600 lb). Female Indian rhinos weigh about 1600 kg. The Indian Rhino is from 5.7–6.7 feet tall and can be up to 13 feet (4.0 m) long. The record-sized specimen of this rhino was approximately 3500 kg. The Indian Rhino has a single horn that reaches a length of between 20 and 101 cm. Its size is comparable to that of the White Rhino in Africa.

The Javan Rhinoceros (Rhinoceros sondaicus) is one of the rarest and most endangered large mammals anywhere in the world.[4] According to 2002 estimates, only about 60 remain, in Java (Indonesia) and Vietnam. Of all the rhino species, the least is known of the Javan Rhino. These animals prefer dense lowland rain forest, tall grass and reed beds that are plentiful with large floodplains and mud wallows. Though once widespread throughout Asia, by the 1930s the rhinoceros was nearly hunted to extinction in India, Burma, Peninsular Malaysia, and Sumatra for the supposed medical powers of its horn and blood.

Like the closely related larger Indian Rhinoceros, the Javan rhinoceros has only a single horn. Its hairless, hazy gray skin fall into folds into the shoulder, back, and rump giving it an armored-like appearance. The Javan rhino's body length reaches up to 3.1-3.2 m (10-10.5 feet), including its head and a height of 1.5–1.7 m (4.9-5.6ft)tall. Adults are variously reported to weigh between 900–1,400 kg[5] or 1,360-2,000 kg.[6] Males horns can reach 26 cm in length while in females they are knobs or no horn at all.[6]
A big bastion of one horn or Indian rhino is the Kaziranga National Park situated in the Golaghat district of Assam

HIPPOPOAMUS



The hippopotamus (Hippopotamus amphibius), from the Greek ἱπποπόταμος (hippopotamos, ιππος hippos meaning "horse" and πόταμος potamus meaning "river"), often shortened to "hippo", is a large, mostly plant-eating African mammal, one of only two extant species in the family Hippopotamidae (the other being the Pygmy Hippopotamus).

The hippopotamus is semi-aquatic, inhabiting rivers and lakes in sub-Saharan Africa in groups of 5-30 hippos. During the day they remain cool by staying in the water or mud; reproduction and childbirth both occur in water, where territorial bulls preside over a stretch of river. They emerge at dusk to graze on grass. While hippos rest near each other in territories in the water, grazing is a solitary activity and hippos are not territorial on land.

Despite their physical resemblance to pigs and other terrestrial even-toed ungulates, their closest living relatives are cetaceans (whales, porpoise, etc.). The common ancestor of whales and hippos split from other even-toed ungulates around 60 million years ago. The earliest known hippopotamus fossils, belonging to the genus Kenyapotamus in Africa, date to around 16 million years ago.

The hippopotamus is recognizable for its barrel-shaped torso, enormous mouth and teeth, hairless body, stubby legs and tremendous size. It is similar in size to the White Rhinoceros; only elephants are consistently heavier. Despite its stocky shape and short legs, it can easily outrun a human. Hippos have been clocked at 30 mph (48 km/h) while running short distances, faster than an Olympic sprinter. The hippopotamus is one of the most aggressive animals in the world, and are often regarded as the most dangerous animal in Africa. There are an estimated 125,000 to 150,000 hippos remaining throughout Sub-Saharan Africa, of which Zambia (40,000) and Tanzania (20,000-30,000) have the largest populations [1]. They are still threatened by poaching for their meat and ivory canine teeth, and by habitat loss.Hippopotamuses are one of the largest mammals. They can live in the water, or go on land. Their specific gravity allows them to sink and walk or run along the bottom of a river. Hippos are considered megafauna, but unlike all other African megafauna, hippos have adapted for a semi-aquatic life in freshwater lakes and rivers.[5]

Because of their enormous size, hippopotamuses are difficult to weigh in the wild. Most estimates of the weight come from culling operations that were carried out in the 1960s. The average weights for adult males ranged between 1500–1800 kg (3,300–4,000 lbs). Females are smaller than their male counterparts, with average weights measuring between 1300–1,500 kg (2,900–3,300 lbs).[5] Older males can get much larger, reaching at least 3,200 kg (7,100 lbs) and occasionally weighing 4500 kg (9900 lbs)[20][21]. Male hippos appear to continue growing throughout their lives; females reach a maximum weight at around age 25.[22]

On the National Geographic Channel television program, "Dangerous Encounters with Brady Barr", Dr. Brady Barr measured the bite pressure of an adult female hippo at 1,821 lb (826 kg) after abandoning an attempt to measure the bite of an adult male due to its aggressiveness.[23]

Hippos average 3.5 meters (11 ft) long, 1.5 meters (5 ft) tall at the shoulder. The range of hippopotamus sizes overlaps with the range of the White Rhinoceros; use of different metrics makes it unclear which is the largest land animal after elephants. Even though they are bulky animals, hippopotamuses can run faster than a human on land. Estimates of their running speed vary from 30 km/h (18 mph) to 40 km/h (25 mph), or even 50 km/h (30 mph). The hippo can maintain these higher speeds for only a few hundred meters.[5]
A bull hippo out of water during daylight, Ngorongoro Crater, Tanzania.
A bull hippo out of water during daylight, Ngorongoro Crater, Tanzania.

A hippo's lifespan is typically 40 to 50 years.[5] Donna the Hippo, 56, is the oldest living hippo in captivity. She lives at the Mesker Park Zoo in Evansville, Indiana.[24][25] The oldest hippo ever was called Tanga; she lived in Munich, Germany, and died in 1995 at the age of 61.[26]
A drawing of a hippopotamus skeleton.
A drawing of a hippopotamus skeleton.

The eyes, ears, and nostrils of hippos are placed high on the roof of the skull. This allows them to be in the water with most of their body submerged in the waters and mud of tropical rivers to stay cool and prevent sunburn. Their skeletal structure is graviportal, adapted to carrying the animals' enormous weight. Hippopotamuses have legs that are small, relative to other megafauna, because the water in which they live reduces the weight burden. Like other aquatic mammals, the hippopotamus has very little hair.[5]
Eye of a hippo in San Francisco Zoo
Eye of a hippo in San Francisco Zoo

Their skin secretes a natural sunscreen substance which is red-colored. The secretion is sometimes referred to as "blood sweat," but is neither blood nor sweat. This secretion is initially colorless and turns red-orange within minutes, eventually becoming brown. Two distinct pigments have been identified in the secretions, one red and one orange. The two pigments are highly acidic compounds. They are known as red pigment hipposudoric acid and orange pigment norhipposudoric acid. The red pigment was found to inhibit the growth of disease-causing bacteria. The light absorption of both pigments peaks in the ultraviolet range, creating a sunscreen effect. All hippos, even those with different diets secrete the pigments, so it does not appear that food is the source of the pigments. Instead, the animals may synthesize the pigments from precursors such as the amino acid tyrosine. [27]

MONKEY


A monkey is any member of either the New World monkeys or Old World monkeys, two of the three groupings of simian primates, the third group being the apes. There are 264 known extant species of monkey.

The New World monkeys are classified within the parvorder Platyrrhini, whereas the Old World monkeys (superfamily Cercopithecoidea) form part of the parvorder Catarrhini, which also includes the apes. Thus, scientifically speaking, monkeys are paraphyletic (not a single coherent group), and Old World monkeys are actually more closely related to the apes than they are to the New World monkeys.

Because of their similarity to monkeys, apes such as chimpanzees and gibbons are often called "monkeys" in informal usage, though they are not monkeys. Conversely, due to its size (up to 1 m/3 ft) the Mandrill is often thought to be an ape, but it is actually an Old World monkey. Also, a few monkey species have the word "ape" in their common name.Monkeys range in size from the Pygmy Marmoset, at 140 to 160 millimetres (5-6 in) long (plus tail) and 120 to 140 grams (4-5 oz) in weight, to the male Mandrill, almost 1 metre (3.3 ft) long and weighing 35 kilograms (77 lb). Some are arboreal (living in trees) while others live on the savannah; diets differ among the various species but may contain any of the following: fruit, leaves, seeds, nuts, flowers, eggs and small animals (including insects and spiders).

Some characteristics are shared among the groups; most New World monkeys have prehensile tails while Old World monkeys have non-prehensile tails or no visible tail at all. Some have trichromatic colour vision like that of humans, others are dichromats or monochromats. Although both the New and Old World monkeys, like the apes, have forward facing eyes, the faces of Old World and New World monkeys look very different, though again, each group shares some features such as the types of noses, cheeks and rumps.

BEAR


Bears (family Ursidae) are mammals in the order Carnivora. Bears are classified as caniforms, or doglike carnivorans, with the pinnipeds being their closest living relatives. Although there are only eight living species of bear, they are widespread, appearing in a wide variety of habitats throughout the Northern Hemisphere and partially in the Southern Hemisphere. That which pertains to bears is called ursine. Bears are found in the continents of North America, South America, Europe, and Asia.

Common characteristics of modern bears include a large body with stocky legs, a long snout, shaggy hair, plantigrade paws with five nonretractile claws, and a short tail. While the polar bear is mostly carnivorous and the giant panda feeds almost entirely on bamboo, the remaining six species are omnivorous, with largely varied diets including both plants and animals.

With the exceptions of courting individuals and mothers with their young, bears are typically solitary animals. They are sometimes diurnal, but are usually active during the night (nocturnal) or twilight (crepuscular). Bears are aided by an excellent sense of smell, and despite their heavy build and awkward gait, they can run quickly and are adept climbers and swimmers. Bears use shelters such as caves and burrows as their dens, which are occupied by most species during the winter for a long period of sleep similar to hibernation.

Bears have been hunted since prehistoric times for their meat and fur. To this day, they play a prominent role in the arts, mythology, and other cultural aspects of various human societies. In modern times, the bear's existence has been pressured through the encroachment of their habitats and the illegal trade of bears and bear parts, including the Asian bile bear market. The IUCN lists six bear species as vulnerable or endangered, and even "least concern" species such as the brown bear are at risk of extirpation in certain countries. The poaching and international trade of these most threatened populations is prohibited, but still ongoing.

DEER


A deer is a ruminant mammal belonging to the family Cervidae. A number of broadly similar animals from related families within the order Artiodactyla (even-toed ungulates) are often also called deer. Male deer grow and shed new antlers each year, as opposed to horned animals such as antelope—these are in the same order as deer and may bear a superficial resemblance, but they are permanently horned.Depending on their size and species, male deer are called bucks (smallest), stags, or bulls (largest) and females are called does, hinds or cows. Young deer are called kids, fawns or calves. A group of deer is commonly called a herd. Hart, from Old English heorot "deer", is an alternative term for a stag, particularly a Red Deer stag past its fifth year (compare with the modern Dutch word hert). The county Hertfordshire is named after a place where deer ford a watercourse. The word hart is not commonly used, but Shakespeare makes several references, punning on the sound-alike "hart" and "heart", for example in Twelfth Night. "The White Hart" and "The Red Hart" are common English pub names. Whinfell Forest once contained a landmark tree called Harthorn[1]. The word "Hart" also exists in Saterfrisian, being a synonym for the Word "Hirsk" which is more similar to the German Word "Hirsch".

The word deer was originally quite broad in meaning, but became more specific over time. In Middle English, der (O.E. dēor) meant a wild animal of any kind (as opposed to cattle, which meant any domestic livestock).[2] This general sense gave way to the modern sense by the end of the Middle English period, around 1500. The German word Tier, the Dutch word dier and the Scandinavian words djur/dyr/dýr, cognates of English deer, still have the general sense of "animal". The adjective of relation pertaining to deer is cervine.

CHEETAH


The cheetah (Acinonyx jubatus) is a typical member of the cat family (Felidae) that is unique in its speed, while lacking climbing abilities. As such, it is placed in its own genus, Acinonyx. It is the fastest land animal, reaching speeds between 112 kilometres per hour (70 mph) and 123 kilometres per hour (76 mph)[3] in short bursts covering distances up to 460 metres (1,500 ft), and has the ability to accelerate from 0 to 110 kilometres per hour (68 mph) in three seconds, greater than most supercars.[4].

The word "cheetah" is derived from the Sanskrit word chitrakāyaḥ, meaning "variegated body", via the Hindi चीता cītā.[5]The cheetah's chest is deep and its waist is narrow. The coarse, short fur of the cheetah is tan with round black spots measuring from 2 centimetres (0.79 in) to 3 centimetres (1.2 in) across, affording it some camouflage while hunting. There are no spots on its white underside, but the tail has spots, which merge to form four to six dark rings at the end. The tail usually ends in a bushy white tuft. The cheetah has a small head with high-set eyes. Black "tear marks" run from the corner of its eyes down the sides of the nose to its mouth to keep sunlight out of its eyes and to aid in hunting and seeing long distances.

The adult cheetah weighs from 40 kilograms (88 lb) to 65 kilograms (140 lb). Its total body length is from 115 centimetres (45 in) to 135 centimetres (53 in), while the tail can measure up to 84 centimetres (33 in) in length. Males tend to be slightly larger than females and have slightly bigger heads, but there is not a great variation in cheetah sizes and it is difficult to tell males and females apart by appearance alone. Compared to a similarly-sized leopard, the cheetah is generally shorter-bodied, but is longer tailed and taller (it averages about 90 centimetres (35 in) tall) and so it appears more streamlined.

Some cheetahs also have a rare fur pattern mutation: cheetahs with larger, blotchy, merged spots are known as 'king cheetahs'. It was once thought to be a separate subspecies, but it is merely a mutation of the African cheetah. The 'king cheetah' has only been seen in the wild a handful of times, but it has been bred in captivity.

The cheetah's paws have semi-retractable claws[6] (known only in three other cat species - the Fishing Cat, the Flat-headed Cat and the Iriomote Cat) offering the cat extra grip in its high-speed pursuits. The ligament structure of the cheetah's claws is the same as those of other cats; it simply lacks the sheath of skin and fur present in other varieties, and therefore the claws are always visible, with the exception of the dewclaw. The dewclaw itself is much shorter and straighter than other cats.

Adaptations that enable the cheetah to run as fast as it does include large nostrils that allow for increased oxygen intake, and an enlarged heart and lungs that work together to circulate oxygen efficiently. During a typical chase its respiratory rate increases from 60 to 150 breaths per minute.[6] While running, in addition to having good traction due to its semi-retractable claws, the cheetah uses its tail as a rudder-like means of steering to allow it to make sharp turns, necessary to outflank prey who often make such turns to escape.

Tuesday, September 2, 2008

Thursday, June 12, 2008

LION



The lion (Panthera leo) is a member of the family Felidae and one of four big cats in the genus Panthera. With exceptionally large males exceeding 250 kg (550 lb) in weight,


it is the second-largest living cat after the tiger. Wild lions currently exist in sub-Saharan Africa and in Asia with a critically endangered remnant population in northwest India, having disappeared from North Africa, the Middle East and western Asia in historic times. Until the late Pleistocene (about 10,000 years ago), the lion was the most widespread large land mammal beside humans. They were found in most of Africa, much of Eurasia from western Europe to India and, in the Americas, from the Yukon to Peru.

In captivity both male and female lions can live for over 20 years. They typically inhabit savanna and grassland, although they may take to bush and forest. Lions are unusually social compared to other cats. A pride of lions consists of related females and offspring and a small number of adult males. Groups of female lions typically hunt together, preying mostly on large ungulates. The lion is an apex and keystone predator, although they will resort to scavenging if the opportunity arises. While lions, in general, do not selectively hunt humans, some have been known to become man-eaters and seek human prey.


Visually, the male is highly distinctive and is easily recognized by its mane. The head of the male lion is one of the most widely recognized animal symbols in human culture. It has been depicted extensively in literature, in sculptures, in paintings, on national flags, and in contemporary films and literature.

HORSE


The horse (Equus caballus) is a large odd-toed ungulate mammal, one of ten living species of the family Equidae.

Most horses perform work such as carrying humans or are harnessed to pull objects such as carts or plows. Hundreds of distinct horse breeds have been developed, allowing horses to be specialized for certain tasks; lighter horses for racing or riding, heavier horses for farming and other tasks requiring pulling power. Some horses, such as the miniature horse, can be kept as pets. In some societies, horses are a source of food, both meat and milk; in others it is taboo to consume these products. In industrialized countries, horses are predominantly kept for leisure and sporting pursuits, while in other parts of the world they are still used as working animals.

Horses and humans have lived and worked together for thousands of years and an extensive specialized vocabulary has arisen to describe virtually every horse behavioral and anatomical characteristic with a high degree of precision.

ELEPHANT


Elephants are a family in the order Proboscidea in the class Mammalia. They were once classified along with other thick skinned animals in a now invalid order, Pachydermata. There are three living species: the African Bush Elephant, the African Forest Elephant (until recently known collectively as the African Elephant), and the Asian Elephant (also known as the Indian Elephant). Other species have become extinct since the last ice age, which ended about 10,000 years ago, the Mammoths being the most well-known of these.

Elephants are mammals, and the largest land animals alive today. The elephant's gestation period is 22 months, the longest of any land animal. At birth it is common for an elephant calf to weigh 120 kilograms (265 lb). An elephant may live as long as 70 years, sometimes longer. The largest elephant ever recorded was shot in Angola in 1956. This male weighed about 12,000 kg (26,400 lb), with a shoulder height of 4.2 m (13.8 ft), a metre (3 ft 4 in) taller than the average male African elephant. The smallest elephants, about the size of a calf or a large pig, were a prehistoric species that lived on the island of Crete during the Pleistocene epoch.

Elephants are symbols of wisdom in Asian cultures and are famed for their memory and high intelligence, where they are thought to be on par with cetaceans and hominids. Aristotle once said the elephant was "the beast which passeth all others in wit and mind."

Elephants are increasingly threatened by human intrusion and poaching. Once numbering in the millions, the African elephant population has dwindled to between 470,000 and 690,000 individuals. The elephant is now a protected species worldwide, with restrictions in place on capture, domestic use, and trade in products such as ivory. Elephants generally have no natural predators, although lions may take calves and occasionally adults. In some areas, lions may regularly take to preying on elephants

Tuesday, June 3, 2008

GIRAFEE

Giraffa camelopardalis) is an African even-toed ungulate mammal, the tallest of all land-living animal species, and the largest ruminant. Males can be 4.8 to 5.5 metres (16 to 18 feet) tall and weigh up to 1,700 kilograms (3,800 pounds). The record-sized bull, shot in Kenya in 1934, was 5.87 m (19.2 ft) tall and weighed approximately 2,000 kg (4,400 lb).[2] Females are generally slightly shorter, and weigh less than the males do.

The giraffe is related to deer and cattle, but is placed in a separate family, the Giraffidae, consisting only of the giraffe and its closest relative, the okapi. Its range extends from Chad to South Africa.

Giraffes can inhabit savannas, grasslands, or open woodlands. They prefer areas enriched with acacia growth. They drink large quantities of water and, as a result, they can spend long periods of time in dry, arid areas. When searching for more food they will venture into areas with denser foliage.
Giraffes have long necks, which they use to browse the leaves of trees. They possess seven vertebrae in the neck (the usual number for a mammal) that are elongated. The vertebrae are separated by highly flexible joints. The base of the neck has spines which project upward and form a hump over the shoulders. They have anchor muscles that hold the neck upright.

LEGS

Giraffes also have slightly elongated forelegs, about 10% longer than their hind legs. The pace of the giraffe is an amble, though when pursued it can run extremely fast. It can not sustain a lengthy chase. Its leg length compels an unusual gait with the left legs moving together followed by right (similar to pacing) at low speed, and the back legs crossing outside the front at high speed. When hunting adult giraffes, lions try to knock the lanky animal off its feet and pull it down. Giraffes are difficult and dangerous prey though, and when attacked the giraffe defends itself by kicking with great force. A single well-placed kick from an adult giraffe can shatter a lion's skull or break its spine. Lions are the only predators which pose a serious threat to an adult giraffe.


Giraffes bending down to drink


Modifications to the giraffe's structure have evolved, particularly to the circulatory system. A giraffe's heart, which can weigh up to 10 kg (22 lb) and measure about 60 cm (2 ft) long, has to generate around double the normal blood pressure for an average large mammal in order to maintain blood flow to the brain against gravity. In the upper neck, a complex pressure-regulation system called the rete mirabile prevents excess blood flow to the brain when the giraffe lowers its head to drink. Conversely, the blood vessels in the lower legs are under great pressure (because of the weight of fluid pressing down on them). In other animals such pressure would force the blood out through the capillary walls; giraffes, however, have a very tight sheath of thick skin over their lower limbs which maintains high extravascular pressure in exactly the same way as a pilot's g-suit.

Behaviour



Female giraffes associate in groups of a dozen or so members, occasionally including a few younger males. Younger males tend to live in "bachelor" herds, with older males often leading solitary lives. Reproduction is polygamous, with a few older males impregnating all the fertile females in a herd. Male giraffes determine female fertility by tasting the female's urine in order to detect estrus, in a multi-step process known as the flehmen response.

Giraffes will mingle with the other herbivores in the African bush. They are beneficial to be around because of their height. A giraffe is tall enough to have a much wider scope of an area and will watch out for predators.



Giraffe gestation lasts between 14 and 15 months, after which a single calf is born. The mother gives birth standing up and the embryonic sack usually bursts when the baby falls to the ground. Newborn giraffes are about 1.8 m (6 ft) tall. Within a few hours of being born, calves can run around and are indistinguishable from a week-old calf; however, for the first two weeks, they spend most of their time lying down, guarded by the mother. The young can fall prey to lions, leopards, spotted hyenas, and wild dogs. It has been speculated that their characteristic spotted pattern provides a certain degree of camouflage. Only 25 to 50% of giraffe calves reach adulthood; the life expectancy is between 20 and 25 years in the wild and 28 years in captivity (Encyclopedia of Animals).

Two males necking.
Two males necking.

As noted above, males often engage in necking, which has been described as having various functions. One of these is combat. Battles can be fatal, but are more often less severe. The longer the neck, and the heavier the head at the end of the neck, the greater the force a giraffe is able to deliver in a blow. It has also been observed that males that are successful in necking have greater access to estrous females, so the length of the neck may be a product of sexual selection.[7]

After a necking duel, a giraffe can land a powerful blow with his head — occasionally knocking a male opponent to the ground. These fights rarely last more than a few minutes or end in physical harm.

Another function of necking is affectionate and sexual, in which two males will caress and court each other, leading up to mounting and climax. Same sex relations are more frequent than heterosexual behaviour. In one area 94% of mounting incidents were of a homosexual nature. The proportion of same sex courtships varies between 30 and 75%, and at any given time one in twenty males will be engaged in affectionate necking behaviour with another male. Females, on the other hand, only appear to have same sex relations in 1% of mounting incidents.[8]

Stereotypic behavior

Many animals when kept in captivity, such as in zoos, display abnormal behaviours. Such unnatural behaviours are known as stereotypic behaviours.[9] In particular, giraffes show distinct patterns of stereotypic behaviours when removed from their natural environment. Due to a subconscious response to suckle milk from their mother, something which many human-reared giraffes and other captive animals do not experience, giraffes resort instead to excessive tongue use on inanimate objects.[10]

Due to the obvious social and cultural discomfort associated with the addition of milk delivery devices, animal enclosures are often enriched with other stimuli, such as food and mental distractions (toys, scent markings etc.). This operates as a distraction, removing the giraffe’s focus from its instinctual tendencies towards suckling, resulting in tongue
Giraffes use their long, prehensile tongues to extend their reach.

The giraffe browses on the twigs of trees, preferring trees of the genus Mimosa; but it appears that it can live without inconvenience on other vegetable food. A giraffe can eat 63 kg (140 lb) of leaves and twigs daily. As ruminants, they first chew their food, swallow for processing and then visibly regurgitate the semi-digested cud up their necks and back into the mouth, in order to chew again. This process is usually repeated several times for each mouthful.

A giraffe will clean off any bugs that appear on its face with its extremely long tongue (about 45 cm/18 in). The tongue is tough on account of the giraffe's diet, which can include thorns from the trees that they eat. In Southern Africa, giraffes feed on all acacias, especially Acacia erioloba, and possess a specially-adapted tongue and lips that are tough enough to withstand, or even ignore, the vicious thorns of this plant.

Sleep

The giraffe has one of the shortest sleep requirements of any mammal, which is between 10 minutes and two hours in a 24-hour period, averaging 1.9 hours per day.[11]

Sounds

Giraffes are thought to be mute; however, although generally quiet, they have been heard to make various sounds. Courting males will emit loud coughs. Females will call their young by whistling or bellowing. Calves will bleat, moo, or make mewing sounds. In addition, giraffes will grunt, snort, hiss, or make strange flute-like sounds. Recent research has shown evidence that the animal communicates at an infrasound level.[12]



Giraffes are hunted for their hides, hair, and meat. In addition, habitat destruction also hurts the giraffe. In the Sahel trees are cut down for firewood and to make way for livestock. Normally, giraffes are able to cope with livestock since they feed in the trees above their heads. The giraffe population is increasingly shrinking in West Africa. However, the populations in eastern and southern Africa are stable and, due to the popularity of privately-owned game ranches and sanctuaries (i.e. Bour-Algi Giraffe Sanctuary), are expanding. The giraffe is a protected species in most of its range. The total African giraffe population has been estimated to range from 110,000 to 150,000. Kenya (45,000), Tanzania (30,000), and Botswana (12,000), have the largest national populations.[13]

An unexpected danger to giraffes in captivity is that, as they are typically the tallest objects in a zoo, giraffes are at increased risk of being struck by lightning. In the wild, this hazard is reduced by the presence of trees; as well, the giraffe's natural habitat range has an extremely low occurrence of lightning -- NASA's satellite lightning detection system indicates that the area receives an average of less than one cloud-to-ground flash per square kilometre per year.[14]

In art and culture


Giraffes can be seen in paintings, including the famous painting of a giraffe which was taken from Africa to China by Admiral Zheng He in 1414. The giraffe was placed in a Ming Dynasty zoo.

The Medici giraffe was a giraffe presented to Lorenzo de Medici in 1486. It caused a great stir on its arrival in Florence, being reputedly the first living giraffe to be seen in Italy since the days of Ancient Rome. Another famous giraffe, called Zarafa, was brought from Africa to Paris in the early 1800s and kept in a menagerie for 18 years.

Giraffe is a novel by the author J M Ledgard. The work concerns a true incident in which 49 giraffes were slaughtered in the Czech Republic (then Czechoslovakia) in 1975 following the suspected outbreak of disease amongst the group. The novel contains extensive information about the species, including the long history of European fascination with the beast and its captivity in zoos.