Polar Bear Facts

Category: Facts

  • 21 Interesting Facts about Polar Bears  

    Did you know facts about polar bears? Perhaps not! Let me take to the Arctic where you get to know some of the special facts about polar bears. Polar bears are probably the only bears that have long fascinated biologists not only for their super strength but for their ability to swim great distances. We have managed to gather some of the most amazing 21 facts about polar bears.

    What are Interesting Facts about Polar Bears?

    • Polar bears were separated from brown bears some 600,000 years ago.
    • They are the largest living carnivorous animals on land. Polar bears are also referred to as marine mammals because they spend much of their lives in water.
    • Scientists believe that they have observed a decrease in the polar bear’s skull size in the last 118 years. This is possibly due to the environmental pollution.
    • A new born polar bear weighs as little as 500 grams whereas a fully grown adult weighs as much as 700 kilograms. The cubs gain weight up to 14 kg in just 3 – 4 months after the birth.
    • The adult male is nearly twice the size of an adult female. While the male polar bear weighs 550 – 650 kg the female measures around 200 – 300 kg in weight.
    • Male polar bears breed with the female which are less than half the size of their own. Males attain maximum size during their 10th birthday.

    Read More: Top 5 Facts about Polar Bears

    interesting facts about polar bears for kids
    By YOHFONG C.
    • Females are thought to breed only once in 2 – 3 years. During pregnancy she will enter into a dormancy (a sort of hibernation) state in a den. In November or December the female gives birth to twins or sometimes three cubs. During sleep the mother polar bear relies on her available fat.
    • Sometimes the cubs in the same den are not real brothers or sisters. They are step brothers. Siblings can have different father.
    • Polar bear cubs are not only blind at birth but they are also deaf. However in couple of months they will grow into the most powerful terrestrial animal.
    • The weight of the bear is supported by the feet. The polar bear’s feet does not only spread the weight but they also facilitate the animal in walking over the thin sheet of ice. They serve as snowshoes. White bears possess tiny pads called papillae under their feet. The papillae prevent the animal from slipping while providing a firm grip on the ice.
    • The white bear is one of the few terrestrial animals which can maintain a speed of about 3.5 miles per hour for many hours.
    • Polar bears are strong swimmers and they can swim as much a distance as 4,500 miles in a single season. One polar bear swam as much as 687 kilometers (426 miles) continuously in 9 days. This is the maximum distance covered by any white bear in a single journey.
    • Polar bears possess one of the greatest home ranges of the animal kingdom. The average range is 350,000 square kilometers.
    • They have black skin and black tongue.
    • While white bears are able to see things in the low light of the arctic the bear’s sight is quite poor. They don’t rely on sight for hunting. Polar bears have nearly the same sight as that of humans.
    • The estimated population of polar bears is 20,000 – 25,000 worldwide. One million ringed seals are needed each year to feed the entire polar bear population.
    • Polar bears appear to be yellow in days when seals are abundant. This is probably due to the oil they eat from the seal—this makes the color of the coat slightly yellow.
    • A female polar bear can go by 4 to 5 months without eating. Yet in starving she never refuses to nurse her cubs. That said, the female white bear is a highly devoted mother.
    • A bear cub who is not a trained swimmer is likely to sit on the mother’s back while the mother swims. This prevents the cub from chilling into the icy water.
    • Polar bears cannot suffer from snow blindness but if we were to spend that much time in the arctic we would surely go blind in just few days. Arctic bears have yellow pigment in the cornea which serves as eyeglasses and prevent the sunlight from damaging.
    • About 60% of the polar bear’s population is found in Canada alone.

  • Why are Polar Bears White? | Polar Bear White Color

    No wonder polar bears appear white for the most part of the year.–except for warmer months when the polar bear’s coat shows yellowish color which is probably due to the oil they take from seals. Compared to adults, young bears display pure white coat one that becomes yellow with age. In captivity however white bears display a shade of green color. The greenish shade is primarily due to the algae that grow inside the bear’s hair. Let’s discuss why are polar bears white all year round?

    Why are Polar Bears White all Year Round?

    • The polar bear’s fur isn’t actually white at all. It only looks like one. This is because there is no pigment in its fur which can change color. A pigment is a material that changes the color of the reflected material.
    • The bear’s furs are hollow and transparent as a result of which they reflect sunlight from the snow. The reflection indeed gives rise to white color. That is why polar bears remain white all throughout the year.
    • Polar bears are protected with 10-cm-thick hide and dense fur which prevent the animal from getting cold. However the bear becomes overheated when it runs longer. That is why polar bears do not usually run. Furthermore white bears cannot survive in warm temperatures exceeding 10o C (50o F) because of the thick fur.
    • The polar bear’s fur consists of two layers; dense underfur and external guard hairs. The guard hairs look white but they are in fact transparent. Both layers serve as leather jacket for polar bears in order to keep them warm even in minus 30 degree centigrade.

    Leaving aside the tip of the nose the polar bear’s entire body is absolutely covered with furs including bear’s foot, claws, and powerful legs. The density of furs is the greatest in all Ursids. No other bear species seem to have this much furred body—not even brown bears. Perhaps this is an adaptation to survive in the extreme cold of the Arctic. The polar bear’s foot is also furred because it provides an added support to walk comfortably on the slippery surface.

    READ: [How Do Polar Bears Adapt to their Environment?]

    why are polar bears white
    Image Courtesy: Ellen Cuylaerts, Underwater & Wildlife photographer (Reproduced with Permission)

    Why Do Polar Bears have Black Skin?

    • Back in 70s scientists studied the polar bear’s adaptations as to its ability to absorb ultraviolet (UV) light.  This was thought to be the remarkable discovery since it forced biologists to think that polar bears might possibly capture energy during the absorption of light.
    • Later findings further suggest the ability to absorb light helps the bear to retain stable body temperature in the harsh arctic environment.
    • The hollow hairs of polar bears (besides attaching algae) also serve as optic fibers in that they provide path to funnel UV light to the skin.
    • It also explains why polar bears have black skin. The black skin is able to absorb such energy without harm.
    • Scientists believe that the absorption of high-frequency energy is indeed an extraordinary adaptation of white bears. Thanks to this characteristic adaptation which has helped polar bears to become Arctic’s deadliest predator—the Great Bear of the North.
    • Sadly perhaps this unique adaptation doesn’t seem to bear any scientific explanation. In the late 90s the scientist Koon found out that the polar bear’s hairs transmit light probably not as efficiently as it absorbs UV light.
    • As the light enters the fur and attempts to go down the shaft, energy is lost or perhaps absorbed, inhibiting much of the energy to get to the skin.

    READ: [Why Do Polar Bears have Black Skins?]

    why are polar bears white
    PHOTOGRAPH BY Ilnar Salakhiev-AP

    What Color is a Polar Bears Fur? | Why Do Polar Bears have Transparent Fur?

    • Polar bears have surprisingly black skin which is visible when the bear loses hair possibly due to some disease. In a bright sunny day in the Arctic the polar bear’s fur looks white and clean. It happens because the fur lacks pigment.
    • That being said, if it lacks pigment the coat must change to any color it gets. As it turns out it does! The fur not only appears white in fact it shows quite a few colors. When the sun rises or sets the polar bear’s coat takes on the yellow-orange hues.
    • Similarly the fur also plays blue color because sometimes the sunlight while passing through clouds and fogs bring blue light.
    • Polar bear’s fur is adapted to take on different colors from the surroundings primarily due to the nature of its hair. The bear’s hairs possess hollow medulla (core) which entertains the impurities.
    • They seem to show pure white coat soon after molting. During spring when the prey density is higher in the arctic waters adult males take on yellowish coat. The off-white or yellow coat is mainly due to the impurities or oil attached to the prey (seals).

    Polar Bear Molting

    Polar bears shed their hair in April to May but the shedding continues all summer. During fall the polar bear covers with shorter hair but in spring the hairs grow longer. They have thick underfur and pelt. The furs have varied lengths.

    Why are Polar Bears White? – Video

    References

    Kolenosky G. B. 1987. Polar bear. pp. 475–485 in Wild furbearer management and conservation in North America (M. Novak, J. A. Baker, M. E. Obbard, and B. Malloch, eds.). Ontario Fur Trappers Association, North Bay, Ontario, Canada.

    Lockwood, Sophie (2006). Polar Bears. Chanhassen, MN: The Child’s World. ISBN 1-59296-501-6.

    Koon, Daniel W. (1998). “Is polar bear hair fiber optic?”. Applied Optics. 37 (15): 3198 3200. Bibcode:1998ApOpt..37.3198K. doi:10.1364/AO.37.003198. PMID 18273269.

  • Polar Bears and Penguins

    Polar bears and penguins live on the opposite poles but under similar environmental conditions. It explains a lot about the evolutionary developments of both species. Polar bears and penguins chemistry doesn’t match or probably should never be for there is a predatory-prey relationship lie between the two. However dissimilar they may appear to be, polar bears and penguins share many similar behavior traits. For instance, both are aquatic species and are exceptional swimmers. In fact penguins are one of the world’s fastest swimmers.

    What do Polar Bears and Penguins have in Common?

    Penguins live in the South Pole while polar bears live in the North Polar. They both live at the opposite ends of the pole. Thus there is no chance that polar bears meet penguins. In order to have interactions between the two either polar bear or penguin must be a great traveler. Ice bears are known to migrate during the ice-free winter but they never get to the Southern Hemisphere.

    Camouflage

    Polar bear’s white coat blends with the snowy background—providing a perfect camouflage against any possible threats. Similarly penguin’s camouflage is due to their countershading appearance making it difficult for marine predators to recognize them from below.

    Insulation

    Polar bears are insulated by their dense furs which are also oily so that water slips away. The polar bear’s hairs are water resistant and thus keep the bear warm in the icy cold water. Penguins are insulated by a thick layer of feathers that keep the bird warm at all times.

    Diving Speed

    Penguins have got the ability to reach the speed of about 6 to 12 km/h (3.7 to 7.5 mph) underwater which is nearly the swimming speed of polar bears. Ice bears typically swim at a speed of 10 km/h. Baby penguins rarely dive just like baby polar bears. Polar bear cubs mount on the mother’s back during swimming.

    Diving Depths

    While polar bears are shallow divers rarely going beyond 5 or 6 feet underwater penguins can reach the depths of about 565 m (1,854 ft). Ice bears can remain submerged for as long as 2 – 3 minutes but penguins can stay underwater for 10 – 15 minutes.

    Social Animals

    Penguins are highly social animals in that they live in colonies consisting of thousands of birds each. Polar bears are lone walkers. They prefer to live a solitary lifestyle.

  • Polar Bear vs Grizzly Bear | Polar Bear vs Brown Bear

    Polar bear (Ursus maritimus) and grizzly bear (Ursos arctos) are not only the largest terrestrial carnivorans, they are close cousins too. Polar bear is the largest whereas brown bear is the second largest terrestrial mammal living today. They both resemble in size and strength. Grizzly bears and polar bears are super powerful. They possess the amazing ability to take down prey nearly the size of their own. Grizzlies are also called North American brown bear and scientists never use the word grizzly for brown bears.

    While there is virtually no chance that brown bear would meet polar bear people often get confused as to who would win polar bear vs grizzly bear fight.

    Polar Bear vs Grizzly Bear Evolution

    The brown bear seems to have evolved from the Asian subspecies Ursus savini about 800,000 years ago. The oldest fossil discovered in China and it is 500,000 years old. Grizzlies are thought to have occupied the Europe around 250,000 years ago.

    Polar bears separated from other carnivorans around 38 million years ago. The oldest fossil discovered in Prince Charles Foreland in 2004 and it is 130,000 – 110,000 years old. The study of fossils suggests that the polar bear’s molar teeth changed drastically from brown bear’s teeth around 10,000 – 20,000 years ago. Before that brown bear and polar bears had the same molar teeth.

    Both polar bears and grizzly bears are genetically same species—DNA proves it. They diverged from one another about 400,000 years ago. Even today in captivity polar and brown bear can mate successfully giving rise to pizzly or groalar bear.

    Who would Win Polar Bear vs Grizzly Bear | Polar Bear vs Grizzly Bear Fight

    It is reasonable to assume that the virtual match between polar bears and grizzly bear would be quite tough because both are extremely muscular and massive in their body size. While brown bears possess longer claws polar bears have got elongated skull with long canines that can rip off the flesh. The comparison is surely a tough one since both animals are absolutely compatible in their physical characteristics.

    Read More: Is a Polar Bear Bigger than a Grizzly Bear?

    Grizzly is more aggressive animal as compared to the polar bears. Polar bears usually avoid fighting and they can even walk away if they see humans but grizzlies will charge against any possible intruder.

    Polar Bear vs Grizzly Bear Size

    Head-and-body Length

    • The overall length of grizzly bear is about 1.4 to 2.8 m (4 ft 7 in to 9 ft 2 in) and it stands 70 to 153 cm (2 ft 4 in to 5 ft 0 in) at the shoulder.
    • Polar bears measures around 2.4–3 meters (7 ft 10 in–9 ft 10 in) in total length and the shoulder height is estimated at 122 to 160 cm (4 ft 0 in to 5 ft 3 in).

    Tail Length

    • Grizzly bears have relatively longer tail than polar bears.
    • The brown bear’s tail measures around 6 to 22 cm (2.4 to 8.7 in) whereas the polar bear’s tail is the shortest of all bear species measuring 7 to 13 cm (2.8 to 5.1 in) in total length.

    Physical Features

    • The polar bear’s body is rather elongated as compared to that of brown bears. The nose and skull are also longer in white bears and shorter in brown bears.
    • Brown bears seem to possess larger ears and legs than polar bear’s.
    • Brown bears also possess longer and sharper claws as compared to their cousins. The polar bear’s claws are used provide a firm grip while walking on the sea ice whereas grizzly bear’s claws are mainly used for digging and killing prey.
    • Polar bears are remarkable swimmers and they are known to swim for days without stopping. Brown bears lack such ability.

    Read More: Polar Bear vs Siberian Tiger

    polar bear vs grizzly bearPolar Bear vs Grizzly Bear Habitat

    • Grizzlies are thought to make homes in a wide variety of habitats such as temperate forests, open or semi-open landscapes, coastal estuaries, steppes, meadows, alpine forests, and desert edges. They have the most diverse habitat ranges of all bear species.
    • The essential characteristics of a polar bear’s habitat are sea ice and water. The reason is that the bear hunts seals on ice floes.

    Polar Bear vs Grizzly Bear Behavior

    • Like polar bears grizzlies can also stand on their hind legs. In fact brown bears can also walk a bit but polar bears can’t.
    • Both species are crepuscular but grizzlies mostly show nocturnal behavior as they prefer to come out at dusk.
    • Grizzlies have a home range of about 115 km2 (44 sq mi). Polar bears have remote ranges.
    • Polar bears are not territorial but brown bears actively defend their territories.
    • In both species males do not take part in raising the cubs.
    • The typical lifespan of brown bears is about 25 years with one captive individual died at the age of 50 years. Polar bears have also the same average life expectancy.
    • Grizzlies are omnivorous while polar bears are exclusively carnivores. Grizzly bear eats salmon, sedges, forbs, plants, shoots, grasses, and carrion. Polar bears feed on ringed and bearded seals.

  • Polar Bear Teeth – Do Polar Bears have Sharp Teeth?

    Scientists weren’t able to explain history of polar bear’s teeth until in 2004 when they discovered 130,000 – 110,000-year-old polar bear jaw bone. This was the oldest jaw bone and its discovery answered many questions and solved numerous puzzles on the skull anatomy of a polar bear. The fossil was found on Prince Charles Foreland. Fossil studies suggest that the polar bear’s molar teeth transformed into a new form around 10,000 – 20,000 years ago and the shape was entirely different from those of brown bear’s teeth. Before that time polar bears and brown bears shared similar teeth characteristics. The arctic bears separated from their brown cousins during the Pleistocene period probably in the eastern Siberia.

    Polar Bears possess typical carnivorous heterodont dentition. Heterodont dentition explains much about the polar bear’s feeding behavior. It is an anatomical explanation of teeth which means that the animal possess more than one tooth morphology. They have teeth of different lengths and shapes. Perhaps you’d love all these interesting polar bear teeth facts.

    Polar Bear Teeth – Do Polar Bears have Sharp Teeth?

    • The polar bear’s teeth are classified into three categories namely; incisors, canines, and cheek teeth (molars and premolars). While larger teeth such as incisors and canines are fixed rostrally the molars and premolars are set caudally inside the mouth.
    • There is a long gap between the functional canine and molariform teeth. Inside the gap lie the first premolars which are vestigial.
    • Thanks to this big gap that allows the bear to pierce into the thick bodies of seals and more importantly without facing any interference from the cheek teeth. Unlike in brown bears the cheek teeth in polar bears are significantly reduced in size and also the carnassials are more pronounced in white bears than in brown bears.
    • These carnassials truly reflect the predatory lifestyle of an arctic bear. Their teeth are perfect to grab the prey and tear it apart.
    • Brown bear’s teeth are well adapted to grinding grasses whereas polar bear’s teeth definitely serve no such purpose. While male polar bears possess larger and heavier canines than those of females the molar arcade is same in both sexes.
    • The ratio of condylobasal length to zygomatic width (L/W) is 1.59 in brown bears but in polar bears the ratio is 1.63. If we look at the canines the difference appears to be greater than the actual measurements.
    • The incisors are attached to the premaxillary bone. The premaxillary bone is attached to the upper jaw of an animal bearing teeth. However canines lie in the maxilla which is quite adjacent to premaxilla.
    • While molar teeth are flat and are mainly used in chewing, the canines, premolars, and incisors are primary or deciduous teeth. The molars grow from maxillae whereas the premolars sprout from the maxillary bones.
    • Polar bears’ teeth serve different functions and none of them resembles the other. This can truly be troublesome provided the bear loses tooth in fight. If one of the teeth is broken then it probably affects the dietary habits of a polar bear.
    • Polar bear’s primary teeth appear to replace vertically and once in a lifetime. This means that if a polar bear loses her deciduous teeth the second time then it must learn to live without deciduous teeth.

    Read More: How Much Do Polar Bears Eat?

    do polar bears have sharp teethFunctions of Polar Bear Teeth

    • Incisors are primarily used either for slicing or for chipping food. The bear can also use (pointed) incisors for cutting thick skin of a seal.
    • The cheek teeth are equally effective in that they help they facilitate in crushing and grinding the food before the molars chew it.
    • Several characteristic features of a skull make up the carnivoran adaptation of a polar bear. The powerful temporal muscles and fossae are used to rip the flesh and also for killing the prey. These muscles also play a part when the bear holds the prey temporarily. Polar bear however cannot divide the flesh inside her mouth with these muscles. The temporal muscles are only used to tear prey.
    • The polar bear’s jaw movement has a limited horizontal motion in fact they are not able to move the upper and lower jaws on sideways. They can have a smooth vertical movement though. Polar bears have shallow mandibular fossae which resembles like that of a dog. They are thought to possess much pronounced dentary as compared to other marine mammals.

    How Do Polar Bears Swallow Food?

    Read More: What Do Polar Bears Eat?

    Polar bears are more likely to swallow food than they chew. The jaw muscles act in coordination with each other to pass the food via oral cavity through the larynx. The bones of the head likely facilitate in swallowing process. The hyoid apparatus which holds the larynx in place supports the tongue is extremely significant while swallowing and feeding. Muscles that will move the hyoid apparatus up and down occur in between basihyal and tongue.

    How Many Teeth Does a Polar Bear have?

    Polar bears are arguably the most carnivorans in the bear family. The only characteristic adaptation that makes icy bears the most carnivorous is their sharp teeth. The polar bear has 42 teeth in total with the cheek teeth appear to be more pointed than in the brown bears. Besides the bear’s canines are not only sharper but also greater in size than in brown bears.

    These large canines describe the exclusive meat-eating ability of a bear more than any other teeth. Polar bears have dental formula of 3.1.4.23.1.4.3 which they share with all other Ursids.

    Polar Bear Teeth – Video

    • POLAR BEAR FEATURES: Polar bears are primarily known for their acute sense of smell. Thanks to its sharp nose with the help of which the bear is able to smell its primary prey (ringed seal) hidden 2 feet under the snow…
    • POLAR BEAR SKULL:The polar bear’s skull is a typical of any other land carnivores. Bears unlike other carnivores have relatively deep and flattened mandibular fossa. The mandibular fossa is called jaw hinge…
    • POLAR BEAR TAXONOMY: Constantine J. Phipps in 1774 was the first one to give polar bears a scientific name Ursus maritimus. Two years later Pallas came up with his scientific name Ursus marinus… 

  • What Does a Polar Bear Sound Like? – Polar Bear Sounds

    Polar bears have a range of vocalizations but they are no noisy animals. Icy bears remain quiet and live solitary lives most of the time. However polar bears’ sounds are heard either during mating season when males attempt to convince its mating partner or when the individuals fight each other.

    Mature male bears produce sounds in order to show aggression either before the fight or during fighting. Prominent among the aggressive sounds is chuffing which is not heard when bears are in good mood. Thus the chuffing sound suggests that the polar bear is not in a good mood at all. They never make chuffing sound while playing. Do you want to know what sound does a polar bear make in tundra?

    What Does a Polar Bear Sound Like?

    Icy bears are thought to produce as many as 3 to 6 different sounds. Each sound shows different behavior of an animal. The polar bear’s sounds include moaning, jaw-chopping, growling, blowing, hissing, whimpering, throaty rumblings, braying, squalling, smacking, roaring, and finally chuffing.

    If you come across a vocal polar bear you’ll notice that she might sound like a tiger or a lion when she roars. The roaring sound is not as clear though but it is good enough to give the impression of a tiger. Sometimes ice bears appear to sound like elephants.

    The sound roaring is sometimes is a call of excitement as most bears roar when they are in a fairly good mood. Aggressive calls include jaw-chopping and growling.

    What does a Polar Bear Sound when she is Angry?

    Polar bears make a repeated call of chuffing when they are angry. While they often avoid fighting and walk away the mother bear produces chuffing sound when she must defend her cubs against an intruder. Male polar bears regularly show strength to the outsider male but they do not do so in order to defend cubs. They will leave mother and cubs soon after mating. Male bears often fight to win over their mating partner. That is why the chuffing sound is typically heard in the mating season rarely in regular days.

    They will produce a chuffing sound with open mouth. Since they utter same chuffing sound in different situations it depends on the context as to what polar bears want to say. Studies suggest that adults also utter chuff sound when they are in distress. It’s like a ‘mayday’ call. While bears mostly live alone sometimes polar bears live in groups. If one of the group members get separated then she might utter a repeated call of chuffing.

    Read More: How do Polar Bears Communicate?

    what does a polar bear sound likeWhen do Female Polar Bears produce a Chuffing call?

    Female bears become more vocal in the first 120 days when they emerge out of their maternity dens. They do so in order to drive out all sorts of threats from her cubs. Unlike adult males female polar bears are devoted mother and they will actively respond to the distress call of their babies. The call is greatest when cubs are only few days old in age. However as the polar bear babies become 3 – 4 months old the mother produces call but only sometimes.

    The mother bear is also likely to chuff when she plays with her cubs. Sometimes she sniffs, or rubs her muzzle against her cubs, or when she bites and paws. She may utter the same chuff sound during all these actions. Similarly, if a mother bear attempts to change her posture she produces a chuff call.

    Polar bear cubs get separated from their mother after attaining one year age (sometimes two years). During this separation moment the mother and a cub will either roar or chuff. Scientists observed that when the mother chuffs the cubs actively respond to her call by coming nearer to her.

    When do Male Polar Bears produce a Chuffing Sound?

    The adult males go away and live a solitary life after mating but when the same male returns to the female (after 2 years) the entire family i.e. mother, father, and cubs begin to chuff. Observation suggests that males utter a chuffing sound when they copulate. Alongside chuffing they also moan during copulation.

    What do Baby Polar Bears Sound Like?

    Polar bear cubs are thought to utter a unique humming sound but they also chuckle during nursing. They also speak right after the birth but the vocalization is not so clear.

    What does a Polar Bear Sound Like? – Video

  • Polar Bear Skull – Skull Information and Facts

    Polar bears (Ursus maritimus) are the most powerful terrestrial carnivores in the Arctic Ocean. In this article we are going to tell you interesting facts about polar bear skull and how it is different from other bears. They will share many morphological features with other strongest carnivores. Carnivorous animals have certain physiological features in common such as jaw, teeth, claw, eyes, and skull. Archaeologists and scientists have long researched the skull of Ursids let alone polar bears. In northern Alaska archaeologists discovered the king polar bear skull following the 2014 storm. The skull tells us about 1,300 years old ecological behavior.

    Polar Bear Skull

    The polar bear’s skull is a typical of any other land carnivores. Bears unlike other carnivores have relatively deep and flattened mandibular fossa. The mandibular fossa is called jaw hinge. Polar bear’s jaw can hardly move sideways though it opens up and down quite freely. The jaw hinge resembles dog’s mandibular fossa.

    Definition of Skull

    The skull is often defined when describing the entire skeleton of the head. Sometimes only cranium comes under the definition of a skull. The cranium is a part that encloses brain, sensory organs, and head. The primary characteristics of an animal are often defined in respect to the primary characteristics of a skull.

    Polar Bear versus Brown Bear’s Skull

    As compared to the brown bear’s the polar bear’s skull appears to be longer and elongated. They also possess longer nose than brown bears. The principle characteristics of a skull are same in all bears with only few differences. Here we are going to discuss polar bear’s skull and compare it with brown bears’.

    Polar bears have one of the largest skulls in the bear’s family—second only to brown bear’s skull. Viewing it laterally the brown bear’s skull seems like little wider whereas white bears have narrower skull across the palate. This is primarily because condylobasal length to zygomatic width ratio is greater in white bears.

    The length-width ratio finally makes the skull narrower. The length-to-width ratio in brown bears is 1.59 whereas in polar bears the ratio is 1.63. It appears as if ratio calculations do not reflect as much the actual difference of the skull because in reality the difference should be more than it suggests. Calculations aren’t wrong but our perception may be! The reason behind the different visual impression is that brown bears have skull little taller as well as there is an overhanging occiput. Furthermore, there is no brow ridge in the brown bear’s skull the absence of which makes the skull rather curvy from canines to the cranium (brain, sensory organs, and upper jaw).

    polar bear skullKing Polar Bear Skull discovered in Alaska

    Archaeologists recently discovered the king polar skull in the northern Alaska. Scientists believe that the skull is one of the largest ever recorded in polar bears which is why they call it a king polar bear skull. The 16-inch-long skull is thought to be 1,300 years old. Besides, archaeologists also say that the discovery of skull might give us hints about indigenous people who lived alongside the mammoth predator.

    The king polar bear skull is likely to take us back in time predating 4,000 years old. Studies indicate that the skull is of an adult polar bear. The forward facing eyes resemble much to the modern bears but it is different from the modern bears. “We don’t know the exact size (of the entire animal), but we do know it was a huge bear,” Jensen, an Utqiaǵvik-based archaeologist, described.

    Polar Bear Skull – Video

  • What Color are Polar Bears? | Polar Bear Skin Color

    People often wonder if the polar bear’s fur is white then its skin is probably white too. That is not quite true. The polar bear’s skin is jet black which is in contrast to the bear’s white fur. One can hardly see the black skin except in situations when a polar bear sheds its hair possibly due to some disease or infection. The black naked portion of the body becomes prominent for as long as it is covered by the hair again. Let’s then discover what color are polar bears actually.

    What Color are Polar Bears?

    Unlike adults, the polar bear cubs have pink-colored skin especially in the first 150 days. Their skin turns black with age. On the contrary, grizzly bears have pink skin not only in cubs but in adults too. That said, white bears have eventually evolved to acquire black skin in adults—probably an adaptation trait. Let us not forget that the present-day polar bears have been evolved from grizzlies. Scientists do not know the primary reason behind this change.

    Back in 70s a group of scientists carried out a study in which they revealed that the bear absorbs ultraviolet light. They thought that the bear’s fur serves as a fiber optic filament in that they transmit light all the way to the skin. This is a sort of thermal warning. Andrew E. Derocher writes in his book, Polar Bears—A Complete guide to their Biology and Behavior, “Fibre optic properties of a polar bear hair appears to be less than a thousandth of a percent of the light traveled 2.5 cm (1 inch).” The loss of ultraviolet light is thought to occur in a fraction of that distance. As it turns out the theory of fiber optic fur does not stand to logic. Yet another reason is that there are certain regions in the Arctic where the sun never sets—at least 6 months a year in summer. Similarly in winter the darkness lasts for nearly half a year. During these days polar bears do not and should not retain the heat—they drive it away.

    Read More: Why are Polar Bears White?

    Polar bears occupy a vast range of Arctic Circle touching many territories including Russia, Denmark, Norway, Canada, and United States including Alaska. These countries have temperature that drops down below the freezing point. But polar bears are safe; thanks to the bear’s thick black skin which gathers sun-rays keeping the bear warm in cold weather.

    what color is a polar bears skin
    Polar bear’s black skin is visible.
    Image Courtesy: World Wildlife Fund

    Polar Bear Skin Color – What Color are Polar Bears?

    It is not only the black skin that keeps the bear warm in fact there is a dense layer of fat beneath the skin which measures 4.5 inches thick. However these fats do not prevent heat loss in polar bears as they swim in the icy cold water. The heat loss is prevented by the polar bear’s fur. Furthermore the thick fatty skin and fur do not allow white bears to run longer because if they do they’d become overheated.

    Read More: Why are Polar Bears White?

    The fatty layer of skin functions much like a thermos in which the heat is trapped keeping the thermos warm. Polar bears are remarkable swimmers and they are able to swim for days or even months if they must. If they had to swim without blubber the body temperature would drop down.

    This shows that the skin plays a significant role in defining the behavioral adaptation of polar bears. Cubs are however not protected by the blubber which is why mother bears mostly hesitate to swim with their cubs. Adult polar bears gain fats by eating seal’s blubber.

    What Color are Polar Bears? – Video

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  • How Do Polar Bears Reproduce? | Polar Bear Reproduction

    The polar bear reproduction likely occurs in days when the seals are abundant. They will reproduce in March or mid-April to May. A male bear will begin tracking the female 100 kilometers far off via smell. Once male gets to the female it insists his partner to mate. If a male finds another wandering male both fight over the female. The fight is not intense as much and the less dominant male usually withdraws. The winner is going to mate with the female. In this article you’ll come to know how do polar bears reproduce in the Arctic tundra.

    Polar bears are polygynous creatures in that their cubs may or may not belong to the same father. The mating partners however live and eats together for as long as 10 to 14 days. During these days ovulation occurs many times. Once the female gets pregnant she eats a lot of food and tries to gather as much fats as she possibly can. The pregnant mother will put on weight almost equal to that of an adult male. Let’s get on with some of the most interesting facts about the polar bear reproduction.

    How Do Polar Bears Reproduce? – Polar Bear Reproduction Facts

    The reproductive biology of a polar bear is not quite different from other bears. Polar bear’s estrus cycle ranges from March to May but the peak days begin in the first week of May. Coitus is most likely to stimulate ovulation. The fertilized egg is thought to be suspended until autumn.

    The gestation period of a polar bear is 195 to 265 days. Cubs are typically born in January but they may not come out of den until March. The average number of cubs is two but three are also common across some of its range especially in Hudson Bay.

    The weaning period ends in spring and the cubs become independent at the age of 2.3 years age. The female may not breed again until the end of lactation period which lasts for about 2 years. The reproductive interval in polar bears is 3 years.

    Read More: How Many Babies Can a Polar Bear have at Time?

    Newborn cubs weigh up to 0.6 kg at birth. They are born blind, hairless and toothless. However cubs may gain weight in a few days up to 10 – 12 kg. They will leave the den after achieving 12 kilograms of weight. The weight continues to increase quickly until the cubs turn one year of age.

    The mother will nurse their young with fat-rich milk. Female polar bears are thought to possess the most nutritious milk of all carnivorous mammals. The nursing peaks in the first year after birth but it gets low in the second year.

    how do polar bears reproduceThe birth doesn’t appear to occur in the same month throughout the arctic. In the Hudson Bay cubs are born in mid-November to mid-December. In some regions the birth occurs in the last days of November. In the Beaufort Sea female bears mostly enter into the den in the early December. In captivity the birth may occur as late as in December 27. The female body condition determines the timing of implantation.

    Male bears become sexually mature at 3 years of age but they are able to breed for as long as 19 years. Normally males attain maturity at 3 – 5 years age.

    The abundance of ringed seals primarily defines the productivity in polar bears. The greater is the number of seals the shortest is the reproductive age. In the Beaufort Sea, the ringed seals are not abundant as much and thus the bears attain maturity at 5 years of age. The female will give her first birth at 6 years age. In the Canadian High Arctic ringed seals occur in high densities. As such females breed at the age of 3 – 4 years of age.

    Read More: When Do Polar Bear Cubs Leave their Mother?

    The number of cubs born is thought to decline as the bear attains 14 years of age. Females are least likely to complete their reproductive cycles before 3 years interval. The interbirth interval increases with the increase in nursing. If the weaning period is about 2.3 years (mostly) the birth interval goes up to 3 years whereas if the weaning completes in 1.3 years then female is able to breed again after 2 years interval.

    How Do Polar Bears Reproduce – Video

  • What Eats Polar Bears? | Polar Bear Predators

    Polar bears (Ursus maritimus) are apex predators as their super strength puts them at the top of the food chain. They are the arctic’s rulers for no other animal—not even the heaviest of the Arctic’s mammals can dare to rival them. It clearly suggests that polar bears do not have any natural predator in the arctic world.  The polar bear is only one of its kind. But polar bear cubs do have some natural predators in the wild. Let us read more about the polar bear predators to see what animals eat polar bears in the Arctic. 

    What Eats Polar Bears? – Polar Bear Predators

    However powerful polar bears may appear to be there is always one predator that can threaten their survival no matter what. And the predator is no other than human. Bears have long suffered from the brutal nature of humans. Every year 50 to 60 polar bears are hunted—some for food purposes while others for commercial reasons.

    The arctic is no place for humans to live on. That is why very few humans have managed to settle in the most inhospitable place on earth. This is probably a good news for polar bears as their habitat might flourish in the absence of humans.

    Polar Bear Cubs Predators

    Read More: Polar Bear Cub

    While adults are powerful enough to deal with any possible threat the cubs are too weak to possess such strength. The chief predators of polar bear cubs are other mature polar bears especially the males. Male bears are less likely to tolerate a female walking with her cubs except in a situation when the entire family is a unit. When the food is scarce adult bears might kill their cubs and eat them. The cannibalism in polar bears is not rare but it only occurs when the bear is too hungry or far too weak to hunt seals.

    Arctic wolves sometimes find and kill polar bear’s cubs in their den. Mother bears are usually devoted and dedicated parents and she always keeps her yearlings closer to her, however when she goes out to hunt leaving her cubs unattended the predator reaches den to kill them.

    How Do Polar Bears Protect themselves from Predators?

    Main Article: How Do Polar Bears Protect Themselves?

    Polar bears don’t need to protect themselves from predators but if they must they would have camouflaged their white color into the arctic’s snowy background. Even scientists couldn’t recognize polar bears when they were taking shots from the air.

    What Eats Polar Bears? – Polar Bear Predators – Video