The Polar Bear
Polar Bear Anatomy
The Polar bear is known as the largest terrestrial carnivore in the world.
Their bodies are designed so they are able to live in very difficult conditions.
They roam the Arctic ice sheets and swim in that region's coastal waters. Polar bears are very strong swimmers, and their large front paws, which they use to paddle, are slightly webbed. Some polar bears have been seen swimming hundreds of miles from land—though they probably cover most of that distance by floating on sheets of ice.
General Information on Polar Bears
The Polar Bear is an extremely large animal, with the males weighing up to 1,500 pounds. The females are only about 800 pounds when they are full grown. Males can be up to 10 feet in length with the females only about 8 feet long. The body of a Polar Bear is very different from that of other types of bears. They claws of the Polar Bear are very sharp as well as designed to make it simple enough for them to walk across the snow and the ice that is plentiful in their natural habitat.
Skeleton and Muscles
The body of a Polar Bear is very long and they are detailed for specific types of movements. As you watch a Polar Bear move on land, you will notice how powerful each stride is. They feature a very long skull as well as a long nose. They have short but stocky legs that they use both for walking on land and to help them swim in the waters. Many believe that the small size of the Polar Bear’s ears and tail don’t match the rest of their body.
Even though the Polar Bear has very short legs, they have long feet. This too seems somewhat out of place. It is believed this design of their feet though helps them to evenly distribute their weight as they move around. They also help them when it comes to swimming which is important considering how much of their lives they do spend in the water.
To help protect their feet, there are pads on the bottom of them. They are designed to give them plenty of traction for walking on the slippery ice. The claws are much shorter than those of other species of bears. They are designed to allow the Polar Bear a way to easily dig and to scoop the ice.
Polar Bears have a mouth full of 42 extremely sharp teeth. Since they are carnivorous, they need them to kill their prey as well as to consume it. Their teeth are longer and sharper than those of the Brown Bear.
Fur
Polar bears live in one of the planet's coldest environments and depend on a thick coat of insulated fur, which covers a warming layer of fat.
The fur of a Polar Bear is either white or tan and very thick. They have several layers of it to keep them warm in the colder region. They also have layers of blubber that further insulates them as the colder times of the year approach.
Young cubs are born with a light brown fur but within a few weeks the white colour Polar Bears are well known for will emerge. In the summer they do have a yellowish colou r to them due to the lighting. It is also common for their fur to take on a yellowish colour as they age.
Experts though believe the skin is black and the fur is clear because it doesn’t have any pigment in it. The white and yellow we see is the result of how light is reflected from those clear hairs. In captivity, the yellow is often more evident than the white if the environment is warm.
The fur of a Polar Bear offers it a layer that insulates them. They can have almost 4 inches of blubber that helps to keep them warm, insulating them as the colder times of the year approach. This is how they are able to live in the harsh conditions and how they are able to swim in freezing water. They have enormous paws that they use like paddles when they swim. The bottoms of their feet have fur on them that provides them with both insulation and traction while on the ice. They have the ability to distribute their weight around the body so that there isn’t too much of an impact on the ice below them.
Senses
The sense of smell is amazing for a Polar Bear and they use this part of their anatomy to find prey and to identify any type of danger that could be lurking around them. They also have very good hearing and vision which makes them tough predators to get away from.
Their sense of smell plays a key role in them being able to detect when seals are at the surface of air holes in the ice. They can detect them up to 1 mile away. They can also detect female seal dens that are up to 3 feet below the surface of the snow. They also have very good vision and hearing. Their senses allow them to thrive in their natural environment.
Hunting
The polar bear is the most carnivorous member of the bear family, and most of its diet consists of ringed and bearded seals. The Arctic is home to millions of seals, which become prey when they surface in holes in the ice in order to breathe, or when they haul out on the ice to rest. Polar bears hunt primarily at the interface between ice, water, and air; they only rarely catch seals on land or in open water.
The polar bear's most common hunting method is called still-hunting: The bear uses its excellent sense of smell to locate a seal breathing hole, and crouches nearby in silence for a seal to appear. When the seal exhales, the bear smells its breath, reaches into the hole with a forepaw, and drags it out onto the ice. The polar bear kills the seal by biting its head to crush its skull. The polar bear also hunts by stalking seals resting on the ice: Upon spotting a seal, it walks to within 100 yd (91 m), and then crouches. If the seal does not notice, the bear creeps to within 30 to 40 feet (9.1 to 12 m) of the seal and then suddenly rushes forth to attack. A third hunting method is to raid the birth lairs that female seals create in the snow.
The polar bear is an enormously powerful predator. It can kill an adult walrus, although this is rarely attempted. Polar bears have also been seen to prey on beluga whales, by swiping at them at breathing holes. Most terrestrial animals in the Arctic can outrun the polar bear on land as polar bears overheat quickly, and most marine animals the bear encounters can outswim it. In some areas, the polar bear's diet is supplemented by walrus calves and by the carcasses of dead adult walruses or whales, whose blubber is readily devoured even when rotten.
Polar bears have also been observed to eat a wide variety of other wild foods, including muskox, reindeer, birds, eggs, rodents, shellfish, crabs, and other polar bears. They may also eat plants, including berries, roots, and kelp, however none of these are a significant part of their diet.
Social
In general, adult polar bears live solitary lives. Yet, they have often been seen playing together for hours at a time and even sleeping in an embrace, and polar bear zoologist Nikita Ovsianikov has described adult males as having "well-developed friendships. Cubs are especially playful as well. Among young males in particular, play-fighting may be a means of practicing for serious competition during mating seasons later in life.
In 1992, a photographer near Churchill took a now widely circulated set of photographs of a polar bear playing with a Canadian Eskimo Dog a tenth of its size. The pair wrestled harmlessly together each afternoon for ten days in a row for no apparent reason, although the bear may have been trying to demonstrate its friendliness in the hope of sharing the kennel's food. This kind of social interaction is uncommon; it is far more typical for polar bears to behave aggressively towards dogs.
Communication
Vocalisations
Adult polar bears vocalize most when they're agitated or threatened. Sounds include hissing, growling, champing of teeth, and chuffing.
Cubs vocalise more often and for diverse reasons. Sounds include hissing, squalling, whimpering, lip smacking, and throaty rumblings.
Mothers warn cubs with a chuffing or braying sound.
Body Language
Polar bears also communicate through sight, touch and smell.
A male polar bear initiates fighting by approaching another male with its head down, mouth closed and eyes averted. The bears usually make contact by gently touching or "mouthing" each other around the face and neck. They then proceed to rear up on their hind legs and try to push each other over with their forepaws.
A mother bear can comfort, protect of punish her cubs by using her body, muzzle, or paws.
Swimming
They anatomy of a Polar Bear also allows it to be a very good swimmer. They can be found up to 200 miles away from the closest piece of land. This is absolutely amazing to researchers, but it also indicates the distance that they are able to cover without any problems when it comes to swimming.
They can also float for very long periods of time due to the amount of fat found on their bodies. It is estimated that their anatomy allows them to swim up to six miles per hour. There is no doubt by researchers that the Polar Bear anatomy has been a work in process over millions of years. They also assume it will continue to change to adapt to their current environment.
Reproduction
Female polar bears reach sexual maturity at about four to five years.
Male polar bears reach secual maturity at about six years, but most males do not successfully mate until around 8 to 10 years and older.
Breeding takes place from March to June on the sea ice, but most breeding occurs during April and May. During the creeding season males and females find each other by congregating int he best seal-hunting habitats.
Male polar bears have been seen following the tracks of breeding female polar bears for more than 100 km (62 mi.). Scientists are uncertain what signals males use to track breeding females. Competition for females is intense. Females breed about once every three years; therefore, there are about three adult males to every breeding female.
Before mating, a female polar bear may be accompanied by several males. The males fight fiercely among themselves until the strongest or largest male succeeds in chasing the others away. A polar bear threatening to attack another polar bear usually lowers its head, flattens its ears back, and gives an open mouth threat with a hiss-like roar.
Fights are rarely fatal, but do result in broken canines and scars on the head, neck, and shoulders.
Dominant males may succeed in mating with several females in a season.
Once paired, the male and female stay together for a week or more.
Females are induced ovulators - the act of mating causes a female to release an egg for fertilization. Polar bears may have many different mates over their lifetime.
Cubs
Females den by digging into deep snow drifts, which provide protection and insulation from the Arctic elements. They give birth in winter, usually to twins. Young cubs live with their mothers for some 28 months to learn the survival skills of the far north. Females aggressively protect their young, but receive no help from their solitary male mates. In fact, male polar bears may even kill young of their species.