Polar Bears: Rulers of the Arctic Realm

The Arctic region is a merciless world. With few species of either plants or animals occurring throughout these glacial lands, creatures are pushed to their limits to survive in the freezing and nearly desolate environment.[1] Winters bring extremely low temperatures and the land becomes shrouded in ice, making plant growth difficult and leaving many creatures with less food sources. Despite these pressing conditions, there are animals which call this demanding environment home. Among the most incredible survivors in all of creation, these creatures are designed to subsist in one of nature’s most extreme ecosystems. This includes the animal which is known by many as the representation of the freezing Arctic, the polar bear. Intelligent, powerful, and possessing no natural enemies, the polar bear is the apex predator of this harsh and unforgiving world.[2] This creature is perfectly designed to survive in the frigid temperatures of the Arctic. However, it is also very vulnerable to alterations in the environment, and thus its future is threatened by the climate changes occurring in its habitat. Studies carried out on these amazing animals have led to a greater understanding of their needs, behavior, and difficult yet incredible lives as they journey through the dangerous realm that is their home. Despite their struggles in a demanding and changing world, polar bears remain undaunted by their constant challenges. They are the most powerful hunters in this frozen land, the rulers of the Arctic realm.

Photograph Source: solarnavigator.net

The polar bear (Ursus maritimus) is a large, bulky mammal which can grow to a length of 2.5 meters and weight of up to 1600 lbs.[3] It is the largest bear species as well as the largest of all land carnivores. This animal possesses a beautiful white coat which protects them from the cold and becomes more yellow during the summer due to oxidation.[4] The white fur also provides the bears with camouflage when hunting. In contrast, their skin possesses a black coloration which is useful in absorbing sunlight and helping to keep the bear warm.[5] Their body shapes are similar to those of other bear species, with the few differences being the polar bears’ smaller heads and more elongated necks. The soles of their broad and powerful paws are insulated with fur, providing aid with traction in ice and snow.[6] These bears are surprisingly excellent swimmers and are capable of swimming for nearly 50 miles. Their bodies are designed for their semi-aquatic lifestyle with powerful sloping shoulders, paddling membranes which web half of their forepaws, and thick, oily fur that sheds seawater and provides insulation to protect the bears from the colder temperatures of the water. The thick layer of blubber they possess also assists in retaining their normal body temperature and also provides the bear with some needed buoyancy when swimming.[7] In short, they are designed to withstand anything their harsh environment throws at them.

Polar bears are both powerful and intelligent creatures. Photograph Credit: Klaus Jost

Polar bears occur in Russia, Greenland, Alaska, and Canada, with the majority of the populations found above the Arctic Circle. The polar bear is a marine species which prefers to live on sea ice. They are most commonly found on ice floes, ice edges, and islands, although they are also observed on land. They are commonly found swimming between these different areas in their search for food.[8] Around the sea ice live plankton which are preyed on by fish. These fish attract seals, which in turn are preyed on by the polar bears that swim to these locations. The sea ice also provides the bears with a temporary home that they can use to rest while they are not hunting the nearby prey. Polar bears also breed and even create maternal dens in these floating ice platforms.[9]

The range of the polar bear. Chart courtesy of www.defenders.org

The polar bear’s large body and need to build up its blubber can sometimes become a curse in a frigid environment containing relatively few creatures. As a result, it must spend most of its waking hours searching for and hunting food.[10] As the most carnivorous member of the bear family, the polar bear spends much of its time hunting ice seals such as ringed and bearded seals. They will also prey on other species of seals depending on the specific location of the bear. However, this mighty carnivore is also known to attack and kill very powerful creatures such as musk oxen. Other prey animals include reindeer, small rodents, sea birds, shellfish, and fish. Since polar bears need to feed as much as possible (healthy bears try to eat more than 4 lbs of fat per day), they will also scavenge on dead animals and will even accept human garbage as food.[11]

Photograph Source: Northrup.org

However, the polar bear’s main prey, seals, can be tricky to catch. Seals often slip back into the water when they spot an approaching bear. Indeed, many bears go four or five days without any food before they succeed in making a kill. However, bears often employ several different hunting strategies that help to heighten their chances of making a kill. The most common one is called “still hunting.”This strategy involves the bear locating an active breathing hole (a place where seals are currently surfacing in order to breathe air) using its excellent sense of smell. Upon locating a breathing hole, the bear will then crouch next to it, out of sight, and remain still and quiet. Once a seal surfaces to breathe, its scent is noticed by the bear. The large predator then rushes into the breathing hole and clamps its powerful jaws around the seal’s head (usually crushing its skull in the process) or upper body. The seal is then dragged out from the breathing hole to be consumed by the bear. Bears are also known to stalk seals resting on ice packs. When a bear is presented with an opportunity to hunt a resting seal, it will quietly approach the seal. At around 100 years, the bear momentarily waits to see if the seal managed to spot it. If not, then it will crouch down and continue to advance toward its target until the bear is only 10-30 meters away from the seal. By that point, the bear will make a dash towards the seal in order to catch it before the seal can make its way back into the water. An interesting variety of this strategy consists of the bear making its way to a resting seal via the water if possible. Once the bear is close enough, the clever predator then powerfully erupts from the water and catches the seal by surprise. This method, although slower and demanding that the bear gets even closer to the seal than it would have to on land, ensures that the seal’s escape route is cut off. Polar bears are also known to uncover birth lairs located under ice where ringed seals give birth during the spring. Using its sense of smell, the bear is able to locate these birth lairs. After discovering one, the polar bear carefully positions itself next to it. It remains quiet and listens for any signs of a seal activity within the lair. If the bear notices any sounds, it then readies itself and rises up on its hind legs. The bear then powerfully crashes down its forepaws onto the ice in order to break the roof of the birth lair. The bear may break though before the seal pup manages to escape, though sometimes the lair’s roof takes several attempts to break if the ice is especially thick.[12] Polar bears hunt these seals due to their high calorie value, often eating only the blubber of their catch in order to maintain a thick layer of fat.[13]

Seals are common prey for polar bears. pitara.com

Polar bears are usually very cautious when hunting large predators like walruses. Polar bears never attack these creatures in the water, as the walruses then gain the advantage and can attempt to kill the bear by driving their long ivory tusks into the bear’s body. On land, however, the bear possesses the advantage. It can then easily outmaneuver the walrus and overpower it. Sometimes the bodies of a polar bear and walrus are found locked together in death. This is the occasional result of battles where a walrus manages to drive its tusks into the bear while the bear also delivers a mortal wound in return, resulting in a painful end for both creatures.[14]

Walruses are occasionally preyed upon by polar bears. Photograph Credit: H. C. Kyllingstad

Polar bears have no natural enemies and are the dominant predators of their range. However, smaller bears are sometimes chased away from their kills by larger individuals. These battles are sometimes unavoidable since food is difficult to attain in this environment. As a result, most large polar bears will never pass up a chance to obtain a free meal by scaring off a younger bear or another predator.

Mating takes place during the summer months from March to June. Males which are around 6 years old begin to search for female bears by following their scent. These bears will then roam the sea ice, following the scent trail until they finally reach the female. Of course, it is possible for several bears to locate the same female. If this occurs, the bears will usually battle over the female. The victor of these fights mates and remains with his female partner for about a week. After this short partnership, the two bears disperse and the male continues his search for more females. Near the end of autumn, female bears begin to search for areas suitable for dens. Once they find a good den spot, they begin digging until the den is deep enough to house them and their cubs. Once settled in the den, the pregnant female’s heart rate slows down from 46 to 27 beats per minute. Usually around two months later (between December and January), the cubs are born in the den. The cubs, usually twins, are tiny; less than 2 lbs when they are born. The warmth of the den, along with the mother’s body heat and her milk (which is very high in fat) keeps the cubs warm as they rapidly grow. In order to get used to the outside temperatures, the cubs make short trips from the den for several days. The cubs are very energetic, and often play with each other. By March or April, the family leaves the den for good and the cubs begin their lives out in the real world. The mother teaches the cubs important survival skills and hunts food for them. She also protects them from any predators daring enough to attempt to hunt one of the cubs. The lessons they learn throughout this time are vital and will determine whether they survive once they become independent. This family lifestyle continues for about 2 years, after which the family finally disperses.[15] Since the Arctic habitat is such a difficult environment to survive in, this family lifestyle is an important part of ensuring the cubs the highest possible chances of survival.

Polar bears usually give birth to cubs. The mothers teach their offspring vital lessons that the young bears will put to use throughout their lives. keepwintercold.org

Polar bears are not currently endangered, with a stable population of up to 25,000 individuals in the wild.[16] However, that may soon change. The biggest danger to the polar bear population is the heightening temperatures in their environment. This increase in temperature has resulted in the continual melting of their habitat’s ice. Since polar bears are dependent on the sea ice as platforms for locating and catching food, its loss could lead to great problems for their nutrition. It also causes difficulties in their breeding behavior since many female bears rely on the ice platforms as areas for digging dens. Seals also use this ice in the same way. With the ice melting away, the seals have had to move to other locations in order to breed, leaving the bears with less prey options. Also, trophy hunting and illegal poaching continue to present a problem for the future stability of the bear population.[17]

Fortunately, many have become aware of the dangers the polar bear population faces. Many are more willing to defend this beautiful and vulnerable creature after learning about the risks to their future. Although there is controversy regarding what would be the best way to protect these unique animals, the goal of saving these bears has become more and more prominent in recent years. The polar bear may very well have a positive future if the right decisions are made.

Although the future of polar bears is threatened by a variety of different problems, many have risen to the defense of these beautiful animals. Photograph Credit: Klaus Jost

Polar bears are amazing in their beauty, design, and great power. They possess no natural enemies and are the dominant predators in a dangerous world where survival is never certain. These intelligent hunters do what they can to survive, and often in creative and clever ways. Though their future is threatened, many are aware of the dangers the polar bear population faces and are willing to defend these creatures. With more and more coming to the defense of the species in recent years, the future of these beautiful mammals may very well be in secure hands. The Arctic’s great ruler may, indeed, live on.

[1] “The Arctic Region.” www.geographicguide.com. Available from http://www.geographicguide.com/arctic.htm. Internet; accessed 24 May 2011.

[2] “Polar Bear.” www.animals.nationalgeographic.com. Available from http://animals.nationalgeographic.com/animals/mammals/polar-bear.html. Internet; accessed 24 May 2011.

[3] Ibid

[4] “Ursus maritimus, Polar Bear.” www.marinebio.org. Available from http://marinebio.org/species.asp?id=171. Internet; accessed 24 May 2011.

[5] “Polar Bear.” www.nwf.org. Available from http://www.nwf.org/Wildlife/Wildlife-Library/Mammals/Polar-Bear.aspx. Internet; accessed 24 May 2011.

[6] “Ursus maritimus, Polar Bear.” www.marinebio.org. Available from http://marinebio.org/species.asp?id=171. Internet; accessed 24 May 2011.

[7] “Polar Bear.” www.bearplanet.org. Available from http://www.bearplanet.org/polarbear.shtml. Internet; accessed 24 May 2011.

[8] “Polar Bear.” www.nwf.org. Available from http://www.nwf.org/Wildlife/Wildlife-Library/Mammals/Polar-Bear.aspx. Internet; accessed 24 May 2011.

[9] “Polar Bear-Habitat, Distribution, and Status.” www.worldwildlife.org. Available from http://www.worldwildlife.org/species/finder/polarbear/habitat.html. Internet; accessed 24 May 2011.

[10] “Polar Bear.” www.bearplanet.org. Available from http://www.bearplanet.org/polarbear.shtml. Internet; accessed 24 May 2011.

[11] “Polar Bear-Diet.” www.worldwildlife.org. Available from http://www.worldwildlife.org/species/finder/polarbear/diet.html. Internet; accessed 24 May 2011.

[12] Ibid

[13] “Ursus maritimus, Polar Bear.” www.marinebio.org. Available from http://marinebio.org/species.asp?id=171. Internet; accessed 24 May 2011.

[14] “Polar Bear.” www.bearplanet.org. Available from http://www.bearplanet.org/polarbear.shtml. Internet; accessed 24 May 2011.

[15] “Polar Bear-Reproduction.” www.worldwildlife.org. Available from http://www.worldwildlife.org/species/finder/polarbear/reproduction.html. Internet; accessed 24 May 2011.

[16] “Polar Bear Conservation.” www.worldwildlife.org. Available from http://www.worldwildlife.org/species/finder/polarbear/polarbear.html. Internet; accessed 24 May 2011.

[17] “Polar Bear.” www.defenders.org. Available from http://www.defenders.org/wildlife_and_habitat/wildlife/polar_bear.php. Internet; accessed 24 May 2011.