Kangaroos are the only large animals to use hopping as a means of locomotion

A kangaroo is a marsupial from the family Macropodidae. In common use the term is used to describe the largest species from this family, especially those of the genus Macropus, Red Kangaroo, Antilopine Kangaroo, Eastern Grey Kangaroo and Western Grey Kangaroo.Kangaroos are endemic to the continent of Australia.Larger kangaroos have adapted much better to changes wrought to the Australian landscape by humans and though many of their smaller cousins are endangered, they are plentiful. They are not farmed to any extent, but wild kangaroos are shot for meat, sport, and to protect grazing land for sheep and cattle.Although there is some controversy, harvesting kangaroo meat has many environmental and health benefits over sheep or cows grazed for meat.

Behaviour

Kangaroos are the only large animals to use hopping as a means of locomotion. The comfortable hopping speed for Red Kangaroo is about 20-25km/h,but speeds of up to 70 km/h can be attained, over short distances, while it can sustain a speed of 40 km/h for nearly two kilometres.This fast and energy-efficient method of travel has evolved because of the need to regularly cover large distances in search of food and water, rather than the need to escape predators.To move at slow speeds, it uses its tail to form a tripod with its two forelimbs. It then raises its hind feet forward, in a form of locomotion called "crawl-walking.

Diet

Different species of kangaroos have different diets, although all are strict herbivores. The Eastern Grey Kangaroo is predominantly a grazer eating a wide variety of grasses whereas some other species include significant amounts of shrubs in the diet.Many species are nocturnal and crepuscular,usually spending the days resting in shade and the cool evenings, nights and mornings moving about and feeding.Because of its grazing, kangaroos have developed specialized teeth. Its incisors are able to crop grass close to the ground, and its molars chop and grind the grass. Since the two sides of the lower jaw are not joined together, the lower incisors are farther apart, giving the kangaroo a wider bite. The silica in grass is abrasive, so kangaroo molars move forward as they are ground down, and eventually fall out, replaced by new teeth that grow in the back.

Blindness

Eye disease is rare but not new among kangaroos. The first official report of kangaroo blindness took place in 1994, in central New South Wales. The following year, reports of blind kangaroos appeared in Victoria and South Australia. By 1996, the disease had spread "across the desert to Western Australia".Australian authorities were concerned that the disease could spread to other livestock and possibly humans. Researchers at the Australian Animal Health Laboratories in Geelong detected a virus called the Wallal virus in two species of midge, believed to have been the carriers.Veterinarians also discovered that less than three percent of kangaroos exposed to the virus developed blindness.

Camel is an even-toed ungulate within the genus Camelus

A camel is an even-toed ungulate within the genus Camelus, bearing distinctive fatty deposits known as humps on its back. There are two species of camels: the dromedary or Arabian camel has a single hump, and the Bactrian camel has two humps. They are native to the dry desert areas of West Asia, and Central and East Asia, respectively.The term camel Arabic جمل derived from the root "beauty",is also used more broadly to describe any of the six camel-like creatures in the family Camelidae: the two true camels, and the four South American camelids, the llama, alpaca, guanaco and vicuña.

Dairy

Camel milk is a staple food of desert nomad tribes and is richer in fat and protein than cow milk. It is said to have many healthful properties. It is used as a medicinal product in India needed and as an aphrodisiac in Ethiopia.Camel milk can readily be made into yogurt, but can only be made into butter or cheese with difficulty. Butter or yogurt made from camel milk is said to have a very faint greenish tinge.Camel milk cannot be made into butter by the traditional churning method. It can be made if it is soured first, churned, and a clarifying agent added, or if it is churned at 24–25 °C,but times vary greatly in achieving results. Until recently, camel milk could not be made into cheese because rennet was unable to coagulate the milk proteins to allow the collection of curds. Under the commission of the FAO, Professor J.P. Ramet of the École Nationale Supérieure d'Agronomie et des Industries Alimentaires was able to produce curdling by the addition of calcium phosphate and vegetable rennet.The cheese produced from this process has low levels of cholesterol and lactose. The sale of camel cheese is limited owing to the low yield of cheese from milk and the uncertainty of pasteurization levels for camel milk which makes adherence to dairy import regulations difficult.

Meat

A camel carcass can provide a substantial amount of meat. The male dromedary carcass can weigh 400 kg or more, while the carcass of a male Bactrian can weigh up to 650 kg.The carcass of a female camel weighs less than the male, ranging between 250 and 350 kg, but can provide a substantial amount of meat. The brisket, ribs and loin are among the preferred parts, but the hump is considered a delicacy and is most favored.It is reported that camel meat tastes like coarse beef, but older camels can prove to be tough and less flavorful.

Military uses

Attempts have been made to employ camels as cavalry and dragoon mounts and as freight animals instead of horses and mules. In some places, such as Australia, some of the camels have become feral and are considered to be dangerous to travelers on camels. The camels were mostly used in combat because of their ability to scare off horses in close ranges, a quality famously employed by the Achaemenid Persians when fighting Lydia, although the Persians usually used camels as baggage trains for arrows and equipment. The horses detest the smell of camels, and therefore, the horses in the vicinity become harder to control. The United States Army had an active camel corps stationed in California in the 19th century, and the brick stables may still be seen at the Benicia Arsenal in Benicia, California, now converted to artists' and artisans' studio spaces. Camels have been used in wars throughout Africa, and also in the East Roman Empire as auxiliary forces known as Dromedarii recruited in desert provinces. During the American Civil War, camels were used at an experimental stage, but were not used any further, as they were unpopular with the men.

Ostrich is a large flightless bird

The Ostrich, Struthio camelus, is a large flightless bird native to Africa. It is the only living species of its family, Struthionidae and its genus, Struthio. Ostriches share the order Struthioniformes with the kiwis, Emus, and other ratites. It is distinctive in its appearance, with a long neck and legs and the ability to run at maximum speeds of about 45 miles per hour , the top land speed of any bird.




Distribution and habitat

Ostriches formerly occupied Africa north and south of the Sahara, Africa south,East Africa of the rain forest belt, and much of Asia Minor.Today Ostriches prefer open land and are native to the savannas and Sahel of Africa, both south and north of the equatorial forest zone.In Southwest Africa they inhabit the semidesert or true desert.They rarely go above 100 metres.The Arabian Ostriches in the Near and Middle East were hunted to extinction by the middle of the 20th century.

Hunting and farming

In Roman times, there was a demand for Ostriches to use in venatio games or cooking. They have been hunted and farmed for their feathers, which at various times have been popular for ornamentation in fashionable clothing.In the 18th century they were almost hunted to extinction; farming for feathers began in the 19th century. The market for feathers collapsed after World War I, but commercial farming for feathers and later for skins became widespread during the 1970s.It is claimed that Ostriches produce the strongest commercial leather.Ostrich meat tastes similar to lean beef and is low in fat and cholesterol, as well as high in calcium, protein and iron.Uncooked, it is dark red or cherry red, a little darker than beef.

Conservation

The wild Ostrich population has declined drastically in the last 200 years, with most surviving birds in game parks or on farms;however, they have a conservation status of Least Concern,with an occurrence range of 12,000,000 km2.

The Peacock are forest birds that nest on the ground

The term peafowl (peacock) can refer to the two species of bird in the genus Pavo of the pheasant family, Phasianidae. The African Congo Peafowl is placed in its own genus Afropavo and is not dealt with here. Peafowl are best known for the male's extravagant tail, which it displays as part of courtship. The male is called a peacock, the female a peahen,though it is common to hear the female also referred to as a "peacock" or "female peacock". The female peafowl is brown or toned grey and brown.

The two species are:

(1) Indian Peafowl.
(2) Green Peafowl.

Behaviour

The peafowl are forest birds that nest on the ground. The Pavo peafowl are terrestrial feeders but roost in trees.Both species of Peafowl are believed to be polygamous. However, it has been suggested that "females" entering a male Green Peafowl's territory are really his own juvenile or subadult young and that Green Peafowl are really monogamous in the wild. The male peacock flares out its feathers when it is trying to get the female's attention.

Diet

Peafowl are omnivorous and eat plant parts, seed heads,flower petals,arthropods and other insects, reptiles, and amphibians.In common with other members of the Galliformes, males possess metatarsal spurs or "thorns" used primarily during intraspecific fights.

Giraffes are one of the world's tallest mammals

The giraffe is one of only two living species of the family Giraffidae, along with the okapi. The family was once much more extensive, with numerous other species. The giraffids evolved from a 3 metres tall antelope-like mammal that roamed Europe and Asia some 30–50 million years ago.From the late Pliocene onwards, the variety of giraffids drastically declined, until only the two surviving species remained. The modern genus Giraffa evolved during the Pliocene epoch, and included a number of other long-necked species, such as Giraffa jumae, that do not survive today.The modern species, Giraffa camelopardalis, appeared during the Pleistocene 1 million years ago.

Diet

The giraffe browses on the twigs of trees, preferring trees of the genera Acacia, Commiphora and Terminalia, and also eats grass and fruit.The tongue is tough due to the giraffe's diet, which can include tree thorns. 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 the vicious thorns of this plant. A giraffe can eat 65 pounds of leaves and twigs daily, but can survive on just 15 pounds.The giraffe requires less food than typical grazing animals because the foliage it eats has more concentrated nutrition and it has a more efficient digestive system.As a ruminant, it first chews its food, then swallows for processing and then visibly regurgitates 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. The giraffe can surivive without water for extended periods.A giraffe will clean off any bugs that appear on its face with its extremely long tongue.

Communication

Although generally quiet and non-vocal, giraffes 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.


SIZE:
Male giraffes are larger than females. Males weigh between 2,400 and 3,000 pounds and stand up to 19 feet tall! Female giraffes weigh between 1,600 and 2,600 pounds and grow to be 16 feet tall.

Spotted Hyena also known as Laughing Hyena

The Spotted Hyena also known as Laughing Hyena, is a carnivorous mammal of the family Hyaenidae, of which it is the largest extant member. Though the species' prehistoric range included Eurasia extending from Atlantic Europe to China,it now only occurs in all of Africa south of the Sahara save for the Congo Basin.Though often mislabeled as cowardly scavengers, spotted hyenas derive the majority of their nourishment by hunting medium sized ungulates,and frequently clash with lions over food and territory.They are highly intelligent among the carnivora, with studies indicating that their social intelligence is on par with some primate species.

Behavior

Spotted hyenas will rest and give birth in dens, which they rarely dig themselves: they will often use the abandoned lairs of warthogs, springhares and jackals.Unlike grey wolves, it is not uncommon for spotted hyenas to accommodate cubs of different litters in one den.Spotted hyenas will sometimes live in close proximity to warthogs, sharing mudholes and sleeping within a few metres of each other.Spotted hyenas may sleep in the open if the weather is not too hot, but otherwise they will rest near lakes, streams or in mud or dense shrubs.Unlike most social carnivores, spotted hyenas still display some atavistic behaviours of their solitary ancestors: spotted hyenas still head out for food alone, but later return to their community.Like other hyenas, spotted hyenas have two anal scent glands, which open into the rectum just inside the anal opening,though these glands are less elaborate than those of other hyena species.

Body language

Spotted hyenas have a complex set of postures in communication. When afraid, the ears are folded flat, and are often combined with baring of the teeth and a flattening of the mane. When attacked by other hyenas or by wild dogs, the hyena lowers its hindquarters.The tail usually hangs down when neutral, though it will change position according to the situation. When a high tendency to flee an attacker is apparent, the tail is curled below the belly. During an attack, or when excited, the tail is carried forward on the back. An erect tail does not always accompany a hostile encounter, as it has also been observed to occur when a harmless social interaction occurs. Although they do not wag their tails, spotted hyenas will flick their tails when approaching dominant animals or when there is a slight tendency to flee.When approaching a dominant animal, subordinate spotted hyenas will walk on the knees of their forelegs in submission.

Vocalisations

The loud "whoop" is a characteristic sound of the African night and is audible for over 5 km or more.It is a rallying cry, which varies in speed and pitch according to the urgency of the situation.Spotted hyenas also whoop to show off as individuals, the rate and style being an indicator of social status. Because of this, spotted hyenas whoop singly rather than in chorus, as wolf packs do to display their collective strength.Giggles and grunt-laughter tend to be emitted in situations of great excitement, and perhaps indicate a conflicting tendency to flee or stay. The giggles, yells and grunts which accompany mass feeding tend to be directed at competing individuals at a carcass, and has the secondary, disadvantageous effect of attracting lions and other spotted hyenas. Soft grunts are made by females calling their cubs.When attacked, spotted hyenas will emit loud growls and whimpers.

Black bear weight tends to vary according to health,age,sex and season

The American black bear is North America's smallest and most common species of bear. It is a generalist animal, being able to exploit numerous different habitats and foodstuffs.The species is not overly dangerous to humans, but has been responsible for a few deaths, as well as property damage and livestock predation.The American black bear has been the source of inspiration for numerous popular cultural depictions of bears, including the Teddy Bear and Winnie the Pooh.

Size

Black bear weight tends to vary according to age, sex, health and season. Seasonal variation in weight is very pronounced: in autumn, their pre-den weight tends to be 30% higher than in spring, when black bears emerge from their dens. Black bears on the East Coast tend to be heavier on average than those on the West Coast. Adult males typically weigh between 125 and 550 lb, while females weigh 33% less at 90–275 lb.The biggest wild American Black Bear ever recorded was a male from North Carolina, shot in 1998, that weighed 400 kg .Adults are 4-6 ft in length, and 2.5-3 ft in shoulder height.The North American Bear Center, located in Ely, Minnesota, is home to the world's largest captive male and female black bears. Ted, the male, weighed 950–1,000 lb in the fall of 2006.Honey, the female, weighed 555.5 lb in the fall of 2007.


Behaviour

In his Great Bear Almanac, Gary Brown lists 20 different sounds in 8 different contexts. Sounds expressing aggression include growls, woofs, snorts, bellows and roars. Sounds expressing contentment include mumbles, squeaks and pants. American black bears tend to be territorial and non-gregarious in nature.Black bears are excellent and strong swimmers, doing so for pleasure and to feed. Black bears climb regularly to feed, escape enemies or to hibernate. Their arboreal abilities tend to decline with age.

Hibernation

Black bears enter their dens to hibernate in October and November. Prior to that time, they typically put on an average of 4 lb of body fat to get them through the seven months during which they fast. Hibernation usually lasts 3–5 months in southern coastal regions.During this time, their heart rate drops from 98 beats per minute to 8 beats per minute.They spend their time in hollowed-out dens in tree cavities, under logs or rocks, in banks, caves, or culverts, and in shallow depressions. Females, however, have been shown to be pickier in their choice of dens, in comparison to males.A special hormone, Leptin is released into their systems, to suppress appetite. Because they do not urinate or defecate during hibernation, the nitrogen waste from the Bear's body is biochemically recycled back into their proteins.

Giant Panda consumes a diet low in nutrition

The Giant Panda is a bear native to central-western and south western China.It is easily recognized by its large, distinctive black patches around the eyes, over the ears, and across its round body. Though it belongs to the order Carnivora, the Giant Panda's diet is 99% bamboo.The Giant Panda lives in a few mountain ranges in central China, mainly in Sichuan province, but also in the Shaanxi and Gansu provinces. Due to farming, deforestation, and other development, the Giant Panda has been driven out of the lowland areas where it once lived.

Behavior

In the wild, the Giant Panda is a terrestrial animal and primarily spends its life roaming and feeding in the bamboo forests of the Qinling Mountains and in the hilly Sichuan Province.Pandas communicate through vocalization and scent marking such as clawing trees or spraying urine.The Giant Panda is able to climb and take shelter in hollow trees or rock crevices but does not establish permanent dens. For this reason, pandas do not hibernate, which is similar to other subtropical mammals, and will instead move to elevations with warmer temperatures.Pandas rely primarily on spatial memory rather than visual memory.

Diet

Despite its taxonomic classification as a carnivore, the Giant Panda has a diet that is primarily herbivorous, which consists almost exclusively of bamboo. However, the Giant Panda still has the digestive system of a carnivore, as well as carnivore-specific genes,and thus derives little energy and little protein from consumption of bamboo.The average Giant Panda eats as much as 9 to 14 kg of bamboo shoots a day. Because the Giant Panda consumes a diet low in nutrition, it is important for it to keep its digestive tract full. The limited energy input imposed on it by its diet has affected the panda's behavior. The Giant Panda tends to limit its social interactions and avoids steeply sloping terrain in order to limit its energy expenditures.Twenty-five species of bamboo are eaten by pandas in the wild, such as Fargesia dracocephala and Fargesia rufa.Only a few bamboo species are widespread at the high altitudes pandas now inhabit. Bamboo leaves contain the highest protein levels; stems have less.

Panda diplomacy

Loans of Giant Pandas to American and Japanese zoos formed an important part of the diplomacy of the People's Republic of China in the 1970s, as it marked some of the first cultural exchanges between the People's Republic and the West. This practice has been termed "Panda Diplomacy".By 1984, however, pandas were no longer used as agents of diplomacy.The standard loan terms include a fee of up to US$1,000,000 per year and a provision that any cubs born during the loan are the property of the People's Republic of China. Since 1998, due to a WWF lawsuit, the United States Fish and Wildlife Service only allows a U.S. zoo to import a panda if the zoo can ensure that China will channel more than half of its loan fee into conservation efforts for the Giant Panda and its habitat.

Horses are adapted to grazing

Horse are anatomy enables them to make use of speed to escape predators and they have a well-developed sense of balance and a strong fight-or-flight instinct. Related to this need to flee from predators in the wild is an unusual trait: horses are able to sleep both standing up and lying down. Female horses, called mares, carry their young for approximately 11 months, and a young horse, called a foal, can stand and run shortly following birth. Most domesticated horses begin training under saddle or in harness between the ages of two and four.Horses and humans interact in a wide variety of sport competitions and non-competitive recreational pursuits, as well as in working activities such as police work, agriculture, entertainment, and therapy.

Teeth

Horses are adapted to grazing. In an adult horse, there are 12 incisors, adapted to biting off the grass or other vegetation, at the front of the mouth. There are 24 teeth adapted for chewing, the premolars and molars, at the back of the mouth. Stallions and geldings have four additional teeth just behind the incisors, a type of canine teeth that are called "tushes". Some horses, both male and female, will also develop one to four very small vestigial teeth in front of the molars, known as "wolf" teeth, which are generally removed because they can interfere with the bit.

Movement

All horses move naturally with four basic gaits: the four-beat walk, which averages 6.4 kilometres per hour ; the two-beat trot or jog at 13 to 19 kilometres per hour; the canter or lope, a three-beat gait that is 19 to 24 kilometres per hour ; and the gallop.The gallop averages 40 to 48 kilometres per hour but the world record for a horse galloping over a short, sprint distance is 88 kilometres per hour .Besides these basic gaits, some horses perform a two-beat pace, instead of the trot.There also are several four-beat "ambling" gaits that are approximately the speed of a trot or pace, though smoother to ride.Ambling gaits are often genetic in some breeds, known collectively as gaited horses.Often, gaited horses replace the trot with one of the ambling gaits.

Behavior

Horses are prey animals with a strong fight-or-flight instinct. Their first response to threat is to startle and usually flee, although they will stand their ground and defend themselves when flight is not possible or if their young are threatened. They also tend to be curious; when startled, they will often hesitate an instant to ascertain the cause of their fright, and may not always flee from something that they perceive as non-threatening.However, through selective breeding, some breeds of horses are quite docile, particularly certain draft horses.Horses are herd animals, with a clear hierarchy of rank, led by a dominant animal.They are also social creatures who are able to form companionship attachments to their own species and to other animals, including humans. They communicate in various ways, including vocalizations such as nickering or whinnying, mutual grooming, and body language. Many horses will become difficult to manage if they are isolated, but with training, horses can learn to accept a human as a companion, and thus be comfortable away from other horses.

Dolphins are among the most intelligent animals

Dolphins are marine mammals that are closely related to whales and porpoises. There are almost forty species of dolphin in seventeen genera. They vary in size from 1.2 m and 40 kg , up to 9.5 m and 10 tonnes .The family Delphinidae is the largest in the Cetacean order, and relatively recent: dolphins evolved about ten million years ago, during the Miocene. Dolphins are among the most intelligent animals and their often friendly appearance and seemingly playful attitude have made them popular in human culture.

Behavior

Dolphins are often regarded as one of Earth's most intelligent animals, though it is hard to say just how intelligent. Comparing species' relative intelligence is complicated by differences in sensory apparatus, response modes, and nature of cognition. Furthermore, the difficulty and expense of experimental work with large aquatic animals has so far prevented some tests and limited sample size and rigor in others.

Jumping and playing

Dolphins occasionally leap above the water surface, sometimes performing acrobatic figures.Scientists are not certain about the purpose of the acrobatics. Possibilities include locating schools of fish by looking at above-water signs like feeding birds, communicating with other dolphins, dislodging parasites or simple amusement.Play is an important part of dolphin culture. Dolphins play with seaweed and play-fight with other dolphins.Dolphins enjoy riding waves and frequently surf coastal swells and the bow waves of boats, at times “leaping” between the dual bow waves of a moving catamaran. Occasionally, they playfully interact with swimmers.

Sleeping

Generally, dolphins sleep with only one brain hemisphere in slow-wave sleep at a time, thus maintaining enough consciousness to breathe and to watch for possible predators and other threats.In captivity, dolphins seemingly enter a fully asleep state where both eyes are closed and there is no response to mild external stimuli. Respiration is automatic; a tail kick reflex keeps the blowhole above the water if necessary. Anesthetized dolphins initially show a tail kick reflex.The Indus river dolphin has a different sleep method from other dolphin species. Living in water with strong currents and potentially dangerous floating debris, it must swim continuously to avoid injury. As a result, this species sleeps in very short bursts which last between 4 and 60 seconds.

Sharks have very distinctive tails

Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago, before the time of the dinosaurs.Since that time, sharks have diversified into 440 species, ranging in size from the small dwarf lanternshark, Etmopterus perryi, a deep sea species of only 17 centimetres in length, to the whale shark, Rhincodon typus, the largest fish, which reaches approximately 12 metres and which feeds only on plankton, squid, and small fish through filter feeding.Shark are generally do not live in freshwater, with a few exceptions such as the bull shark and the river shark which can live both in seawater and freshwater.They respire with the use of five to seven gill slits. Sharks have a covering of dermal denticles that protect their skin from damage and parasites and improve fluid dynamics so the shark can move faster. They have several sets of replaceable teeth.

Tails

Sharks have very distinctive tails. The tails of sharks vary considerably between species and are adapted to the lifestyle of the shark. The tail provides thrust and so speed and acceleration are dependent on tail shape. Different tail shapes have evolved in sharks adapted for different environments. Sharks possess a heterocercal caudal fin in which the dorsal portion is usually noticeably larger than the ventral portion. This is due to the fact that the shark's vertebral column extends into that dorsal portion, allowing for a greater surface area for muscle attachment which would then be used for more efficient locomotion among the negatively buoyant cartilaginous fishes.

Teeth

The teeth of sharks are embedded in the gums rather than directly fixed to the jaw, and are constantly replaced throughout the shark's life. Multiple rows of replacement teeth are grown in a groove on the inside of the jaw and moved forward in a "conveyor belt"; some sharks lose 30,000 or more teeth in their lifetime. The rate of tooth replacement varies from once every 8–10 days to several months.The shape of a shark's tooth depends on its diet: those that feed on mollusks and crustaceans have dense flattened teeth for crushing, those that feed on fish have needle-like teeth for gripping, and those that feed on larger prey such as mammals have pointed lower teeth for gripping and triangular upper teeth with serrated edges for cutting. The teeth of plankton-feeders such as the basking shark are greatly reduced and non-functional.

Behavior

The classic view describes a solitary hunter, ranging the oceans in search of food. However, this applies to only a few species, with most living far more sedentary, benthic lives. Even solitary sharks meet for breeding or at rich hunting grounds, which may lead them to cover thousands of miles in a year.Migration patterns in sharks may be even more complex than in birds, with many sharks covering entire ocean basins. However, shark behavior has only begun to be formally studied, so there is much more to learn.When approached too closely some sharks perform a threat display to warn off prospective predators. This usually consists of exaggerated swimming movements, and can vary in intensity according to the threat level.

Sleep

Some sharks can lie on the bottom while actively pumping water over their gills, but their eyes remain open and actively follow divers. When a shark is resting, it does not use its nares, but rather its spiracles. If a shark tried to use its nares while resting on the ocean floor, it would be sucking up sand rather than water. Many scientists believe this is one of the reasons sharks have spiracles. The spiny dogfish's spinal cord rather than its brain, coordinates swimming, so it is possible for spiny dogfish to continue to swim while sleeping.It is also possible that sharks sleep in a manner similar to dolphins,one cerebral hemisphere at a time, thus maintaining some consciousness and cerebral activity at all times.

Hearing

Although it is hard to test sharks' hearing, they may have a sharp sense of hearing and can possibly hear prey many miles away.A small opening on each side of their heads leads directly into the inner ear through a thin channel. The lateral line shows a similar arrangement, which is open to the environment via a series of openings called lateral line pores. This is a reminder of the common origin of these two vibration- and sound-detecting organs that are grouped together as the acoustico-lateralis system.

Elephants are the largest land animals now living

Elephants are large land mammals in two genera of the family Elephantine: Elephas and Loxodonta. Three species of elephant are living today: the African Bush Elephant, the African Forest Elephant and the Asian Elephant. All other species and genera of Elephantidae are extinct, some since the last ice age: dwarf forms of mammoths may have survived as late as 2,000 BC.Elephants are the largest land animals now living.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. They typically live for 50 to 70 years, but the oldest recorded elephant lived for 82 years.This male weighed about 12,000 kilograms,with a shoulder height of 4.2 metres, a metre taller than the average male African elephant.

African Elephant
The Elephants of the genus Loxodonta, known collectively as African elephants, are currently found in 37 countries in Africa.African elephants are distinguished from Asian elephants in several ways, the most noticeable being their much larger ears. In addition, the African elephant is typically larger than the Asian elephant and has a concave back. In Asian elephants only males have tusks, but both males and females of African elephants have tusks and are usually less hairy than their Asian cousins.African elephants have traditionally been classified as a single species comprising two distinct subspecies, namely the savanna elephant and the forest elephant, but recent DNA analysis suggests that these may actually constitute distinct species.This split is not universally accepted by experts and a third species of African elephant has also been proposed.

Asian Elephant
The Asian elephant, Elephas maximus, is smaller than the African. It has smaller ears, and typically, only the males have large external tusks.The world population of Asian elephants are also called Indian Elephants is estimated to be around 60,000, about a tenth of the number of African elephants. More precisely, it is estimated that there are between 38,000 and 53,000 wild elephants and between 14,500 and 15,300 domesticated elephants in Asia with perhaps another 1,000 scattered around zoos in the rest of the world.The Asian elephants' decline has possibly been more gradual than the African and caused primarily by poaching and habitat destruction by human encroachment.

Diet
Elephants are herbivores, and spend up to 16 hours a day eating plants. Their diet is highly variable, both seasonally and across habitats and regions. Elephants are primarily browsers, feeding on the leaves, bark, and fruits of trees and shrubs, but they may also eat considerably grasses and herbs. As is true for other non-ruminant ungulates, elephants only digest approximately 40% of what they eat.They make up for their digestive system's lack of efficiency in volume.

Skin
Elephants are colloquially called pachyderms, which means thick-skinned animals. An elephant's skin is extremely tough around most parts of its body and measures about 2.5 centimetres thick. However, the skin around the mouth and inside of the ear is paper-thin. Normally, the skin of an Asian is covered with more hair than its African counterpart. This is most noticeable in the young. Asian calves are usually covered with a thick coat of brownish red fuzz. The species of elephants are typically grayish in colour, but the Africans very often appear brown or reddish from wallowing in mud holes of coloured soil. Wallowing is an important behaviour in elephant society. Not only is it important for socialization, but the mud acts as a sunscreen, protecting their skin from harsh ultraviolet radiation. Although tough, an elephant's skin is very sensitive. Without regular mud baths to protect it from burning, as well as from insect bites and moisture loss, an elephant's skin would suffer serious damage. After bathing, the elephant will usually use its trunk to blow dirt on its body to help dry and bake on its new protective coat.