Animal Encyclopedia

Human interactions of Sea Lion

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Some species of sea lion are readily trainable and are often a popular attraction at zoos and aquariums. The archetypal circus "seal" performing behaviors such as throwing and catching balls on its nose and clapping is almost always a sea lion.

Sea lions have been trained by the U.S. Navy's Marine Mammal Program, based in San Diego, to detain scuba divers.

Sea lion attacks on humans are rare. In a highly unusual attack in 2007 in Western Australia a sea lion leapt from the water and seriously mauled a 13-year old girl surfing behind a speedboat. The sea lion appeared to be preparing for a second attack when the girl was rescued. An Australian marine biologist opined the sea lion may have viewed the girl "like a rag doll toy" to be played with. In San Francisco where an increasingly large population of California sea lion crowds dock along San Francisco Bay, there have been incidents in recent years of swimmers being bitten on the leg by large aggressive males, possibly as a territorial act.

The Moche people of ancient Peru worshipped the sea and its animals. They often depicted sea lions in their art.

Sea lions have also been reported to assist or save humans who show signs of distress in the open waters. In June of 2000, Kevin Hines leaped into the San Francisco bay and it was reported that he was saved by a sea lion that kept him afloat and breathing till the paramedics arrived.

Social behavior and reproduction of Sea Lion

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Mating occurs between August and December, and the pups are born between December and February. Males arrive first and defend territories, but switch to female defense as they were joined by them. Males defend females from neighbours and intruders with threat displays and by fighting, and forcefully hold pre-estrous females near them. On rocky beaches, males defend small territories where females aggregate and herd them. On more open cobble or sandy beaches, males stay along the surf line and try to herd females going to sea to cool down or forage. The number of actual fights between males depends on the number of females in heat. The first males to arrive have the longest tenures and achieve the most copulations. Males are usually able to keep around three females in their harem, but some have as many as 18.

During the breeding season, males that fail to secure territories and females (mostly subadults) will cause group raids in an attempt to change the status-quo and gain access to the females. These raids cause chaos in the breeding harems, often splitting mothers from their young. The resident males are unable to fight off all the raiders and keep all the females in their territorial boundaries. Nevertheless, raiders are often unsuccessful securing a female. Sometimes an invading male will abduct pups, possibly as an attempt to control the females. They may also take pups as substitutes for mature females. Pups are often severely injured or killed when this happens. Group raids are more common on sandy beaches than rocky ones.

Sea lion mothers remain with their newborn pups for nearly a week, and then start a routine of taking trips back into the sea for food and coming back to nurse the pups. They will act aggressively to other females who come close to their pups, as well as alien pups who try to get milk from them. Pups first enter the water at about four weeks and are weaned at about 12 months. This is normally when the mother gives birth to a new pup. Pups gradually spent more time in the nearshore surf and develop swimming skills.

South American sea lions are observed to make various vocalizations and calls which differs between sexes and ages. Adult males will make high-pitched calls during aggressive interactions, barks when establishing territories, growls when interacting with females, and exhalations which are made after agonistic encounters. Females who have pups make what is called a mother primary call when interacting with their pups, and grunts during aggressive encounters with other females. Pups make what are called pup primary calls. Some of those vocalizations and acoustic features may support individuality.

South American Sea Lion

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The South American sea lion (Otaria flavescens, formerly Otaria byronia), also called the southern sea lion and the Patagonian sea lion, is a sea lion found on the Chilean, Peruvian, Uruguayan, Argentine and Southern Brazilian coasts. It is the only member of the genus Otaria. Its scientific name was subject to controversy, with some taxonomists referring to it as Otaria flavescens and others referring to it as Otaria byronia. The former eventually won out. Locally, it is known by several names though the most common ones are lobo marino (sea wolf) and león marino (sea lion).

The South American sea lion is perhaps the archetypal sea lion in appearance. Males have a very large head with a well-developed mane, making them the most lionesque of the eared seals. They are twice the weight of females. Both males and females are orange or brown coloured with upturned snouts. The manes on males are lighter than females, and female fur on the head and neck is lighter than that of males. Pups are born greyish orange ventrally and black dorsally and moult into a more chocolate colour.

The South American sea lion's size and weight can vary considerably. Adult males can grow over 2.73 m (9 ft) and weigh up to 350 kg (770 lb). Adult females grow up to 1.8–2 m (6–7 ft) and weigh about half the weight of the males, around 150 kg (330 lb). These sea lions are the most sexually dimorphic of the five sea lion species.

As its name suggests, the South American sea lion is found along the coast and offshore islands of South America. It ranges from Peru south to Chile in the Pacific and then north to southern Brazil in the Atlantic. It generally breeds in the southern part of its range and travels north in winter and spring. Notable breeding colonies include Lobos Island, Uruguay; Peninsula Valdes, Argentina; Beagle Channel and the Falkland Islands. Some individuals wander as far north as southern Ecuador, although apparently they never bred there.

South American sea lions prefer to breed on beaches made of sand, but will breed on gravel, rocky or pebble beaches, as well. They can also be seen on flat rocky cliffs with tidepools. Sea lion colonies are more scattered on rocky beaches than sand, gravel or pebble beaches. The colonies make spaces between each individual when it is warm and sunny. They can also be found in marinas and wharves but do not breed there.

South American sea lions feed on a variety of fish, including Argentine hake and anchovies. They also eat cephalopods, such as shortfin squid, Patagonian squid and octopus. They have even been observed preying on penguins, pelicans and young South American fur seals. South American sea lions normally hunt in shallow waters less than five miles from shore. They often forage at the ocean floor for slow moving prey, but they will also hunt schooling prey in groups. When captured, the prey is shaken violently and torn apart. South American sea lions have been recorded to take advantage of the hunting efforts of dusky dolphins, feeding on the fish they herd together. The sea lions themselves are preyed on by orcas and sharks.

Size, Age and Skin of Crocodile

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Size greatly varies between species, from the dwarf crocodile to the saltwater crocodile. Species of Palaeosuchus and Osteolaemus grow to an adult size of just 1 metre (3.3 ft) to 1.5 metres (4.9 ft). Larger species can reach over 4.85 metres (15.9 ft) long and weigh well over 1,200 kilograms (2,600 lb). Crocodilians show pronounced sexual dimorphism with males growing much larger and more rapidly than females. Despite their large adult size, crocodiles start their life at around 20 centimetres (7.9 in) long. The largest species of crocodile is the saltwater crocodile, found in eastern India, northern Australia, throughout south-east Asia, and in the surrounding waters.

Two larger certifiable records are both of 6.2 metres (20 ft) crocodiles. The first crocodile was shot in the Mary River in the Northern Territory of Australia in 1974 by poachers and measured by wildlife rangers. The second crocodile was killed in 1983 in the Fly River, Papua New Guinea. In the case of the second crocodile it was actually the skin that was measured by zoologist Jerome Montague, and as skins are known to underestimate the size of the actual animal, it is possible this crocodile was at least another 10 cm longer.

The largest crocodile ever held in captivity is an Estuarine–Siamese hybrid named Yai (Thai: ใหญ่, meaning big) (born 10 June 1972) at the famous Samutprakarn Crocodile Farm and Zoo, Thailand. This animal measures 6 m (19.69 ft) (19 ft 8 in) in length and weighs 1114.27 kg.

The largest captive crocodile alive in the US is located in South Carolina. In June 2002, Alligator Adventure introduced Utan, born in 1964 in Thailand. At 20 feet (6.1 m) long and weighing in at more than a ton, "Utan", the largest crocodile to ever be exhibited in the United States, made his new home in Myrtle Beach.

Wildlife experts, however, argue that the largest crocodile so far found in the Bhitarkanika was almost 23 feet (7.0 m) long, which could be traced from the skull preserved by the Kanika Royal Family. The crocodile was shot near Dhamara in 1926 and later its skull was preserved by the then Kanika King. Crocodile experts estimate the animal was between 20 feet (6.1 m) and 23 feet (7.0 m) long, as the size of the skull was measured one ninth of the total length of the body.

There is no reliable way of measuring crocodile age, although several techniques are used to derive a reasonable guess. The most common method is to measure lamellar growth rings in bones and teeth—each ring corresponds to a change in growth rate which typically occurs once a year between dry and wet seasons. Bearing these inaccuracies in mind, the oldest crocodilians appear to be the largest species. C. porosus is estimated to live around 70 years on average, and there is limited evidence that some individuals may exceed 100 years. One of the oldest crocodiles recorded died in a zoo in Russia. A male freshwater crocodile at the Australia Zoo is estimated to be 130 years old. He was rescued from the wild by Bob Irwin and Steve Irwin after being shot twice by hunters. As a result of the shootings, this crocodile (known affectionately as "Mr. Freshy") has lost his right eye.

Crocodiles have smooth skin on their belly and side, while their dorsal surface is armoured with large osteoderms. The armoured skin has scales and is thick and rugged, providing some protection. They are still able to absorb heat through this thick, rugged armour as a network of small capillaries push blood through the scales to absorb heat.

Biology and behaviour of Crocodile

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Crocodiles are ambush hunters, waiting for fish or land animals to come close, then rushing out to attack. As cold-blooded predators, they have a very slow metabolism, and thus can survive long periods without food. Despite their appearance of being slow, crocodiles are top predators in their environment, and various species have been observed attacking and killing sharks.

Herodotus claimed that Nile crocodiles have a symbiotic relationship with certain birds like the Egyptian plover, which enter the crocodile's mouth and pick leeches that have been feeding on the crocodile's blood, but there is no evidence of this interaction actually occurring in any crocodile species, and it is most likely mythical or allegorical fiction.

Many large crocodilians swallow stones (called gastroliths or stomach stones) which may act as ballast to balance their body or assist in crushing food, similar to grit in birds.

Salt glands are present in the tongues of most crocodylids and they have a pore opening on the surface of the tongue. They appear to be similar to those in marine turtles; they seem to be absent in Alligatoridae.

Crocodilians can produce sounds during distress and in aggressive displays. They can also hear well and the tympanic membranes are concealed by flat flaps that may be raised or lowered by muscles.

Crocodiles eat fish, birds, mammals and occasionally smaller crocodiles.

Crocodiles are protected in many parts of the world, but they also are farmed commercially. Their hide is tanned and used to make leather goods such as shoes and handbags, whilst crocodile meat is also considered a delicacy. The most commonly farmed species are the Saltwater and Nile crocodiles, while a hybrid of the Saltwater and the rare Siamese Crocodile is also bred in Asian farms. Farming has resulted in an increase in the Saltwater crocodile population in Australia, as eggs are usually harvested from the wild, so landowners have an incentive to conserve crocodile habitat.

Crocodiles are more closely related to birds and dinosaurs than to most animals classified as reptiles, the three being included in the group Archosauria ('ruling reptiles'). See Crocodilia for more information.

Crocodile embryos do not have sex chromosomes, and unlike humans sex is not determined genetically. Sex is determined by temperature, with males produced at around 31.6 °C (89 °F), and females produced at slightly lower and higher temperatures. The average incubation period is around 80 days, and also is dependent upon temperature.

Crocodiles may possess a form of homing instinct. Three rogue saltwater crocodiles were relocated 400 kilometres by helicopter in northern Australia but had returned to their original locations within three weeks, based on data obtained from tracking devices attached to the reptiles.

The land speed record for a crocodile is 17 km/h (11 mph) measured in a galloping Australian freshwater crocodile. Maximum speed varies from species to species. Certain types of crocodiles can indeed gallop, including Cuban crocodiles, New Guinea crocodiles, African dwarf crocodiles, and even small Nile crocodiles. The fastest means by which most species can move is a kind of "belly run", where the body moves in a snake-like fashion, limbs splayed out to either side paddling away frantically while the tail whips to and fro. Crocodiles can reach speeds of 10 or 11 km/h (around 7 mph) when they "belly run", and often faster if they're slipping down muddy riverbanks. Another form of locomotion is the "high walk" where the body is raised clear off the ground.

Crocodiles do not have sweat glands and release heat through their mouths. They often sleep with their mouths open and may even pant like a dog.

It is reported that when the Nile crocodile has lurked a long time underwater to catch prey, and thus has built up a big oxygen debt, when it has caught and eaten that prey, it closes its right aortic arch and uses its left aortic arch to flush blood loaded with carbon dioxide from its muscles directly to its stomach; the resulting excess acidity in its blood supply makes it much easier for the stomach lining to secrete more stomach acid to quickly dissolve bulks of swallowed prey flesh and bone.

Crocodile

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A crocodile is any species belonging to the family Crocodylidae (sometimes classified instead as the subfamily Crocodylinae). The term can also be used more loosely to include all extant members of the order Crocodilia: i.e. the true crocodiles, the alligators and caimans (family Alligatoridae) and the gharials (family Gavialidae), as well as the Crocodylomorpha which includes prehistoric crocodile relatives and ancestors. Member species of the family Crocodylidae are large aquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia. Crocodiles tend to congregate in freshwater habitats like rivers, lakes, wetlands and sometimes in brackish water. They feed mostly on vertebrates like fish, reptiles, and mammals, sometimes on invertebrates like molluscs and crustaceans, depending on species. They first appeared during the Eocene epoch, about 55 million years ago.

The word crocodile comes from the Ancient Greek κροκόδιλος (crocodilos), "lizard," used in the phrase ho krokódilos ho potamós, "the lizard of the (Nile) river."

There are several variant Greek forms of the word attested, including the later form κροκόδειλος (crocodeilos) found cited in many English reference works. In the Koine Greek of Roman times, crocodilos and crocodeilos would have been pronounced identically, and either or both may be the source of the Latinized form crocodīlus used by the ancient Romans.

Crocodilos/crocodeilos itself is a compound of krokè ("pebbles"), and drilos/dreilos ("worm"). It is ascribed to Herodotus, supposedly to describe the basking habits of the Egyptian crocodile. However the word drilos is only attested as a colloquial term for "penis". The meaning of krokè is explained as describing the skin texture of lizards (or crocodiles) in most sources, but is alternately claimed to refer to a supposed habit of (lizards or crocodiles) basking on pebbly ground.

The form crocodrillus is attested in Medieval Latin. It is not clear whether this is a medieval corruption or derives from alternate Greco-Latin forms (late Greek corcodrillos and corcodrillion are attested).

A (further) corrupted form cocodrille is found in Old French and was borrowed into Middle English as cocodril(le). The Modern English form crocodile was adapted directly from the Classical Latin crocodīlus in the 16th Century, replacing the earlier form.

Description of Crocodiles

Crocodiles are among the more biologically complex reptiles despite their prehistoric look. Unlike other reptiles, they have a cerebral cortex; a four-chambered heart; and the functional equivalent of a diaphragm, by incorporating muscles used for aquatic locomotion into respiration (e.g. M. diaphragmaticus); Their external morphology on the other hand is a sign of their aquatic and predatory lifestyle. A crocodile’s physical traits allow it to be a successful predator. They have a streamlined body that enables them to swim swiftly. Crocodiles also tuck their feet to their sides while swimming, which makes them faster by decreasing water resistance. They have webbed feet which, although not used to propel the animal through the water, allow it to make fast turns and sudden moves in the water or initiate swimming. Webbed feet are an advantage in shallower water where the animals sometimes move around by walking.

Crocodiles have a palatal flap, a rigid tissue at the back of the mouth that blocks the entry of water. The palate has a special path from the nostril to the glottis that bypasses the mouth. The nostrils are closed during submergence. Like other archosaurs, crocodilians are diapsid, although their post-temporal fenestrae are reduced. The walls of the braincase are bony but they lack supratemporal and postfrontal bones. Their tongues are not free but held in place by a membrane which limits movement; as a result, crocodiles are unable to stick out their tongues.

Crocodilian scales have pores that are believed to be sensory, analogous to the lateral line in fishes. They are particularly seen on their upper and lower jaws. Another possibility is that they are secretory, as they produce an oily substance that appears to flush mud off.

Crocodiles are very fast over short distances, even out of water. Since crocodiles feed by grabbing and holding onto their prey, they have evolved sharp teeth for tearing and holding onto flesh, and powerful muscles that close the jaws and hold them shut. These jaws can bite down with immense force, by far the strongest bite of any animal. The pressure of the crocodile's bite is more than 5,000 pounds per square inch (30,000 kPa), compared to just 335 pounds per square inch (2,300 kPa) for a rottweiler, 400 pounds per square inch (2,800 kPa) for a large great white shark, 800 pounds per square inch (6,000 kPa) to 1,000 pounds per square inch (7,000 kPa) for a hyena, or 2,000 pounds per square inch (10,000 kPa) for a large alligator[citation needed]. The jaws are opened, however, by a very weak set of muscles. Crocodiles can thus be subdued for study or transport by taping their jaws or holding their jaws shut with large rubber bands cut from automobile inner tubes. They have limited lateral (side-to-side) movement in their neck.

See also :

Physical Description of Brown Bear

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Brown bears have very large and curved claws, those present on the forelimbs being longer than those on the hind limbs. They may reach 5 to 6 centimetres (2.0 to 2.4 in) and sometimes 7 to 10 centimetres (2.8 to 3.9 in) along the curve. They are generally dark with a light tip, with some forms having completely light claws. Brown bear claws are longer and straighter than those of American black bears. The claws are blunt, while those of a black bear are sharp.

Adults have massive, heavily built concave skulls, which are large in proportion to the body. The forehead is high and rises steeply. The projections of the skull are well developed when compared to those of Asian black bears: the latter have sagittal crests not exceeding more than 19–20% of the total length of the skull, while the former have sagittal crests comprising up to 40–41% of the skull's length.

Skull projections are more weakly developed in females than in males. The braincase is relatively small and elongated. There is a great deal of geographical variation in the skull, and presents itself chiefly in dimensions. Grizzlies, for example, tend to have flatter profiles than European and coastal American brown bears. Skull lengths of Russian bears tend to be 31.5 to 45.5 centimetres (12.4 to 17.9 in) for males, and 27.5 to 39.7 centimetres (10.8 to 15.6 in) for females. The width of the zygomatic arches in males is 17.5 to 27.7 centimetres (6.9 to 11 in), and 14.7 to 24.7 centimetres (5.8 to 9.7 in) in females.

Brown bears have very strong teeth: the incisors are relatively big and the canine teeth are large, the lower ones being strongly curved. The first three molars of the upper jaw are underdeveloped and single crowned with one root. The second upper molar is smaller than the others, and is usually absent in adults. It is usually lost at an early age, leaving no trace of the alveolus in the jaw. The first three molars of the lower jaw are very weak, and are often lost at an early age. Although they have powerful jaws, brown bear jaws are incapable of breaking large bones with the ease of spotted hyenas.

The dimensions of brown bears fluctuate very greatly according to sex, age, individual, geographic location, and season. The normal range of physical dimensions for a brown bear is a head-and-body length of 1.7 to 2.8 meters (5.6 to 9.2 ft) and a shoulder height of 90 to 150 centimeters (35–60 in). The smallest subspecies is the Eurasian brown bear, whose mature females weigh as little as 90 kg (200 lb). Barely larger, grizzly bears from the Yukon region (which are a third smaller than most grizzlies) can weigh as little as 100 kg (220 lb) in the spring and the Syrian brown bear, with mature females weighing as little as 150 kg (330 lb).

The largest subspecies are the Kodiak bear, Siberian brown bear, and the bears from coastal Russia, Alaska, and British Columbia. It is not unusual for large males in coastal regions to stand over 3 m (9.8 ft) while on their hind legs, and to weigh up to 680 kg (1,500 lb). The heaviest recorded brown bear weighed over 1,150 kilograms (2,500 lb). Brown bears have long, thick fur, with a moderately long mane at the back of the neck. In India, brown bears can be reddish with silver tips, while in China, brown bears are bicolored with a yellow-brown or whitish cape across the shoulders.

North American grizzlies can be dark brown (almost black) to cream (almost white) or yellowish brown. Black hairs usually have white tips. The winter fur is very thick and long, especially in northern subspecies, and can reach 11 to 12 centimetres (4 to 5 in) at the withers. The winter hairs are thin, yet rough to the touch. The summer fur is much shorter and sparser, and its length and density varies geographically.

Grizzly – The Polar Bear Hybrid

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A grizzly–polar bear hybrid (also pizzly bear, prizzly bear or grolar bear) is a rare ursid hybrid that has occurred both in captivity and in the wild. In 2006, the occurrence of this hybrid in nature was confirmed by testing the DNA for a strange-looking bear that had been shot near Sachs Harbour, Northwest Territories on Banks Island in the Canadian Arctic. Ursid hybrids, a term that designates any hybrid of two species within the family Ursidae, include several other types of polar bear hybrids. Polar bear hybrids with grizzly bears in the wild have been reported and shot in the past as well, but DNA techniques were not available to verify the bears' ancestry.

With three confirmed cases and other suspected sightings, zoologists are hypothesizing how wild hybrids might come into being. Although the two species are genetically similar and often found in the same territories, they tend to avoid each other in the wild. They also fill different ecological niches. Grizzlies (and also Kodiak bears and "Alaskan brown bears", which are all subspecies of the brown bear, Ursus arctos), tend to live and breed on land. Polar bears prefer the water and ice, usually breeding on the ice. The yellowish-white MacFarlane's bear, a mysterious animal known only from one specimen acquired in 1864, seems to attest that grizzly-polar bear hybrids may have always occurred from time to time. Another theory suggests that the polar bears have been driven southward by the melting of the ice cap, bringing them into closer contact with grizzly bears.

On 8 April 2010, David Kuptana, an Inuvialuit hunter from the nearby community of Ulukhaktok on Victoria Island shot what he thought was a polar bear. After inspecting the bear and having DNA testing done, it was found that the bear's mother was a grizzly-polar hybrid and the father was a grizzly bear. The Department of Environment and Natural Resources for the NWT said that it "...may be the first recorded second-generation polar-grizzly bear hybrid found in the wild." The bear possesses physical characteristics intermediate between grizzlies and polar bears, such as brown fur on its paws, long claws and a grizzly-like head.

Biologists affiliated with the American Museum of Natural History and City College of the City University of New York have prepared a new report published in Canadian Field Naturalist that offers the first documented evidence that grizzlies are migrating into polar bear territory. Researchers found that seven grizzlies had been spotted in Wapusk National Park south of Churchill, Manitoba, between 2003 and 2008.

Since the 2006 discovery placed the hybrid into the spotlight, the media have referred to this animal with several portmanteau names, such as pizzly, grolar bear, and polizzly, but there is no consensus on the use of any one of these terms. Canadian wildlife officials have suggested calling the hybrid "nanulak", taken from the Inuit names for polar bear (nanuk) and grizzly bear (aklak). By one convention the name of the sire comes first in such combinations: the offspring of a male polar bear and a female grizzly would be the suggested nanulak or a "pizzly bear", while the offspring of a male grizzly and a female polar bear would be a "grolar bear" or possibly an aknuk. If the remains of MacFarlane's 1864 specimen - which was validly described according to ICZN rules - would be traced and confirmed to be such a hybrid by ancient DNA techniques, the scientific name Ursus × inopinatus would be available for these animals.

Two grizzly–polar bear hybrids were born at Osnabrück Zoo in 2004 (one female and one male), and their physical traits are generally an intermediate between the polar bear and the grizzly bear. For example, their bodies are smaller than polar bears, but larger than grizzlies, while their heads fall between the broader grizzly head and the leaner polar bear head. They have long necks like polar bears, but small shoulder humps like grizzlies. The soles of the hybrids' feet are partially covered in hair; polar bears have hair-covered soles, which act as insulation, and grizzlies have hairless soles. Similarly, the hair of the hybrids exhibits a pattern of hollowness, which blends the traits of both polar bears and grizzlies. In cross section, the hair of polar bears is hollow, while the hair of grizzlies is either solid or has small hollow regions.

This varies according to which part of the grizzly the hair is located. In the hybrid male, the paw hair was solid, but the dark back hair was somewhat hollow, albeit with "smaller empty regions than found in polar bear hair". The hair of the female hybrid, "contains a range of hollow regions". The hybrids demonstrated behavior more similar to polar bears than grizzlies. They stamped toys similar to how polar bears break ice, and hurled bags to the side "as polar bears may hurl prey". Grizzlies given the same bags do not demonstrate this hurling behavior. The hybrids were also observed lying down similar to polar bears: on their stomachs with rear legs splayed.

Subspecies of Brown Bear

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There is little agreement on classification of brown bears. Some systems have proposed as many as 90 subspecies, while recent DNA analysis has identified as few as five clades. DNA analysis recently revealed that the identified subspecies of brown bears, both Eurasian and North American, are genetically quite homogeneous, and that their genetic phylogeography does not correspond to their traditional taxonomy. As of 2005, 16 subspecies have been recognized. The subspecies have been listed as follows:

East Siberian brown bear	Eurasian Brown Bear	Grizzly Bear
Himalayan Brown Bear	Kamchatka Brown Bear	Kodiak Bear
Syrian Brown Bear	Tibetan Blue Bear	Ussuri Brown Bear

Other subspecies of Brown Bear

Subspecies Name	Distribution	Description
Ursus Arctos Nelsoni – Mexican Grizzly Bear (Extinct)	Northern Mexico, including Chihuahua, Coahuila, and Sonora, southwestern United States including southern ranges of Texas, Arizona, and New Mexico	This bear is believed extinct due to cattle ranching in both the United States and Mexico. Distinct in its ability to survive arid conditions, it could live in both montane pine forests of Mexico and canyonlands of Sonoran Desert.
Ursus arctos sitkensis	Baranof Island	Appearing to be more closely related to the polar bear than to other brown bears, this species is called "clade I" by Waits, and others., and is part of the subspecies identified as U. a. sitkensis, by Hall and as U. a. dalli by Kurtén.
Ursus arctos marsicanus Marsican brown bear	Marsica (a small zone in Central Italy)	No Description
Ursus arctos stikeenensis	No information	No Description
Ursus arctos alascensis	Alaska	No Description
Ursus arctos californicus – California golden bear	California	No Description
Ursus arctos crowtheri – Atlas bear	California	No Description
Ursus arctos dalli	No information	No Description

Ursus Arctos, The Brown Bear

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The brown bear (Ursus arctos) is a large bear distributed across much of northern Eurasia and North America. It can weigh from 300 to 780 kilograms (660 to 1,700 lb) and its largest subspecies, the Kodiak Bear, rivals the polar bear as the largest member of the bear family and as the largest land-based predator.

There are several recognized subspecies within the brown bear species. In North America, two types are generally recognized, the coastal brown bear and the inland grizzly, and the two types could broadly define all brown bear subspecies. Grizzlies weigh as little as 350 lb (159 kg) in Yukon, while a brown bear, living on a steady, nutritious diet of spawning salmon, from coastal Alaska and Russia can weigh 1,500 lb (682 kg). The exact number of overall brown subspecies remains in debate.

While the brown bear's range has shrunk, and it has faced local extinctions, it remains listed as a least concern species by the IUCN, with a total population of approximately 200,000. Its principal range countries are Russia, the United States (mostly in Alaska), Canada, the Carpathian region (especially Romania, but also Ukraine, Slovakia, and so on), the Balkans, Sweden and Finland, where it is the national animal. The brown bear is the most widely distributed of all bears.

The brown bear is sometimes referred to as the bruin, from Middle English, based on the name of the bear in History of Reynard the Fox, translated by William Caxton, from Middle Dutch bruun or bruyn, meaning brown (the color). During the Old West, the grizzly was termed "Old Ephraim" and sometimes as "Moccasin Joe". Brown bears are thought to have evolved from Ursus etruscus. The oldest fossils occur in China from about 0.5 million years ago. They entered Europe about 250,000 years ago, and North Africa shortly after.

Brown bear remains from the Pleistocene period are common in the British Isles, where it is thought they outcompeted cave bears. The species entered Alaska 100,000 years ago, though they did not move south until 13,000 years ago. It is thought brown bears were unable to migrate south until the extinction of the much larger Arctodus simus. Several paleontologists suggest the possibility of two separate brown bear migrations: grizzlies are thought to stem from narrow-skulled bears which migrated from northern Siberia to central Alaska and the rest of the continent, while Kodiak bears descend from broad-skulled bears from Kamchatka, which colonized the Alaskan peninsula. Brown bear fossils discovered in Ontario, Ohio, Kentucky and Labrador show the species occurred farther east than indicated in historic records.

See Also :

Subspecies of Brown Bear
Grizzly - Polar Bear Hybrid
Physical Description of Brown Bear
Distribution and Habitat of Brown Bear
Behavior Brown Bear

Bear - The Monster of Carnivora

2011-09-06T12:19:00.000+08:00

Bears are mammals of the family Ursidae. 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. 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 generally diurnal, but may be active during the night (nocturnal) or twilight (crepuscular), particularly around humans. 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. In autumn some bear species forage large amounts of fermented fruits which affects their behaviour. 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 on its 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.

The English word "bear" comes from Old English bera and belongs to a family of names for the bear in Germanic languages, in origin from an adjective meaning "brown". In Scandinavia the word for bear is björn (or bjørn), and is a relatively common given name for males. The use of this name is ancient and has been found mentioned in several runestone inscriptions. In Germanic culture, the bear was a symbol of the warrior, as evident from the Old English term beorn which can take the meaning of both "bear" and "warrior". The reconstructed Proto-Indo-European name of the bear is *h₂ŕ̥tḱos, whence Sanskrit r̥kṣa, Avestan arša, Greek ἄρκτος (arktos), Latin ursus, Welsh arth (whence perhaps "Arthur"), Albanian ari, Armenian arj.

Also compared is Hittite ḫartagga-, the name of a monster or predator. In the binomial name of the brown bear, Ursus arctos, Linné simply combined the Latin and Greek names. The Proto-Indo-European word for bear, *h₂ŕ̥tḱos seems to have been subject to taboo deformation or replacement in some languages (as was the word for wolf, wlkwos), resulting in the use of numerous unrelated words with meanings like "brown one" (English bruin) and "honey-eater" (Slavic medved). Thus some Indo-European language groups do not share the same PIE root. The theory of the bear taboo is taught to almost all beginning students of Indo-European and historical linguistics; the putative original PIE word for bear is itself descriptive, because a cognate word in Sanskrit is rakṣas, meaning "harm, injury".

Unlike most other members of the Carnivora, bears have relatively undeveloped carnassial teeth, and their teeth are adapted for a diet that includes a significant amount of vegetable matter. The canine teeth are large, and the molar teeth flat and crushing. There is considerable variation in dental formula even within a given species. It has been suggested that this indicates bears are still in the process of evolving from a carnivorous to a predominantly herbivorous diet. Polar bears appear to have secondarily re-evolved fully functional carnassials, as their diet has switched back towards carnivory. The dental formula for living bears is: Upper: 3.1.2-4.2, lower: 3.1.2-4.3

The bears are mostly found in the northern hemisphere, with a single species, the spectacled bear, occurring in South America. The Atlas Bear, a subspecies of the Brown Bear, was the only bear native to Africa. It was distributed in North Africa from Morocco to Libya, but has been extinct since around the 1870s. All the other species are found in North America, Asia and Europe. The most widespread species is the Brown Bear, which occurs from Western Europe eastwards through Asia to the western areas of North America. The American Black Bear is restricted to North America, and the Polar bear is restricted to the Arctic Sea. All the remaining species are Asian. With the exception of the Polar Bear the bears are mostly forest species. Some species, particularly the Brown Bear, may inhabit or seasonally use other areas such as alpine scrub or tundra.

While many people think that bears are nocturnal, they are in fact generally diurnal, active for the most part during the day. The belief that they are nocturnal apparently comes from the habits of bears that live near humans which engage in some nocturnal activities, such as raiding trash cans or crops while avoiding humans. The sloth bear of Asia is the most nocturnal of the bears, but this varies by individual and females with cubs are often diurnal in order to avoid competition with males and nocturnal predators. Bears are overwhelmingly solitary and are considered to be the most asocial of all the Carnivora. Liaisons between breeding bears are brief, and the only times bears are encountered in small groups are mothers with young or occasional seasonal bounties of rich food (such as salmon runs)

Alligator

2011-09-05T17:56:00.002+08:00

An alligator is a crocodilian in the genus Alligator of the family Alligatoridae. There are two extant alligator species: the American alligator (Alligator mississippiensis) and the Chinese alligator (Alligator sinensis). The name alligator is an anglicized form of el lagarto, the Spanish term for "lizard", which early Spanish explorers and settlers in Florida called the alligator. Alligators have a variety of successful adaptations to their ecological niche that have allowed these reptiles to remain almost unchanged since the Cretaceous. The alligator is notorious for its bone-crushing bites. In addition, the alligator has been described as a "living fossil", having been extant for 200 million years, beginning in the Mesozoic Era.

A large adult American alligator's weight and length is 800 pounds (360 kg) and 13 feet (4.0 m) long[citation needed], but can grow to 14.5 feet (4.4 m) long and weigh over 1,000 pounds (450 kg). According to the Everglades National Park website, the largest alligator ever recorded in Florida was 17 feet 5 inches (5.31 m), although according to the Florida Fish and Wildlife Conservation Commission web site the Florida state record for length is a 14 feet 5/8 inches (4.28 m) male from Lake Monroe in Seminole County. The largest specimen ever recorded was found in Louisiana and measured 19 feet 2 inches (5.84 m). The Chinese alligator is smaller, rarely exceeding 7 feet (2.1 m) in length. Alligators have an average of 75 teeth. There is no measured average lifespan for an alligator. A specimen named Muja has resided in the Belgrade Zoo in Serbia since 1937, making it at least 73 years old. Another specimen, Čabulītis, in Riga Zoo, Latvia died in 2007 being more than 75 years old.

When young, alligators eat fish, insects, snails, crustaceans, and worms. As they mature, progressively larger prey is taken, including larger fish such as gar, turtles, various mammals, birds, deer and other reptiles. Their stomachs also often contain gizzard stones. They will even consume carrion if they are sufficiently hungry. Adult alligators can take razorbacks and deer and are well known to kill and eat smaller alligators. In some cases, larger alligators are known to ambush dogs, Florida panther and black bears, making it the apex predator throughout its distribution. As humans encroach onto their habitat, attacks are few but not unknown. Alligators, unlike the large crocodiles, do not immediately regard a human upon encounter as prey, but may still attack in self-defense if provoked.

Human uses Alligators are raised commercially for their meat and skin, which is used for bags and shoes.

Also reading :

Habitat and Behavior of Alligator

Alligator Reproduction and Anatomy