BIO 318-C01

Kennedy Ng
BIO 318-C01
Prof. Christine Gleason
Words Count: 807 Polar Bear Creature Feature
The North Pole is a place where land and sea covered in ice, and temperatures can be reached as
low as negative fifty degree Celsius. A new iceberg forms every second in the North Pole, and on average
these icebergs are the size of the thirty story building. The polar bears usually live in the Arctic Circle,
near the North Pole (Hunter, 2010). Despite the harsh conditions, yet there is a rich variety of biodiversity
and the home of the Ursus maritimus, Polar bears. Their genus is Ursus meaning bear and their species is
maritimus meaning marine (Amstrup and DeMaster, 2003).
Polar bears are mammals, which means they are warm-blooded, have fur, and feed their babies
milk. An adult polar bear is an average two and a half meters long and eight hundred kilograms in weight
(Amstrup and DeMaster, 2003). Hollow spaces between its toes create a vacuum effect allowing it to grip
the ground easily. Also, the web structure between its toes allows them to swim comfortably (Amstrup
and DeMaster, 2003). In fact, a bear can swim at speeds of up to ten kilometers an hour, and it can travel
up to one hundred kilometers without needing to rest (Amstrup and DeMaster, 2003).
Polar bears can keep their body warm in the cold environment because they are insulated by up to
four inches of fat and have two layers of fur, a dense undercoat, and an outer coating. The fiber-optics
properties of their fur prevent heat loss and transfer heat from the sun’s rays to their skin. Under their fur,
there is a ten-centimeter thick layer of fat which completely insulates the bear from the cold. Therefore,
the fur allows the bear to maintain its thirty-seven-degree body temperature for extended periods of time
either in the water or on the ice.
Male polar bears which can be twice the size of female polar bears initiate mating in the spring,
and they will track fertile female (Amstrup and DeMaster, 2003). After mating in the spring, the fertile
bear will gain a massive amount of weight by eating. In the fall, the female will get pregnant and live
alone for four months in the dens (Amstrup and DeMaster, 2003). When the cub is born, they will spend
another four months together in the dens. Female polar bears usually give birth to two cubs, but six out of
ten cubs will die from starvation, accidents, or predation (Amstrup and DeMaster, 2003).
For most of their lives, the polar bears are solitary hunters (Durner, 2009). The polar bears have to
travel long distances to hunt in ice surface (Durner, 2009). They rely on their sense of smell, their nose is
exceptionally sensitive and can detect their prey more than thirty kilometers away. After the hibernation
period in the spring season, they are foraging for food to build their essential fat reserves ready for a long
summer season (Hunter, 2010). They are Earth largest living land carnivores and have no natural
predators (Durner, 2009). They feed primarily on seals, but seasonally, they feed on seaweed.
Despite their seemingly untouchable position at the top of the food chain, their future is in danger.
The rapid depletion of sea ice is a direct consequence of a warming climate, the single greatest threat to
the polar bear’s survival (Durner, 2009). Climate change or Global warming resulted from human
activities such as burning the fossil fuels such as gas and oil (Amstrup and DeMaster, 2003). Due to
Global warming, the polar bears having a shorter winter which means the ice surface is melting (Hunter, 2010 and Durner, 2009). As a result, the bear got a shorter time to hunt for their prey such as seals and
they will have a longer time to go without any food (Hunter, 2010).
When not competing for foods or mates, polar bears are social and engage in complex
interactions. Polar bears are long-lived and very intelligent. In fact, females will aggressively defend their
cubs against intruders, including human. Sometimes, the human and bears interaction can result in a death
of human or polar bears themselves. However, unregulated sports hunting is ended in 1973 when northern
countries agreed to preserve polar bears (Hunter, 2010 & Amstrup and DeMaster, 2003).
Today, Polar bears are considered vulnerable meaning species faces a high risk of extinction in
the wild. The extinction of the polar bears will have a large impact on biodiversity. Polar bears are on the
top of the food chain, and they regulated Artic environment. The loss of polar bears will result in
overpopulation of one species such seals population. Overpopulation of seals will have a direct lead to
underpopulation of several species, fish and crustaceans for instance. The loss of fish and crustaceans will
intervene in the food web system, may result in the accumulation and extinction of another species. Work Cited
Hunter, Christine M., et al. "Climate change threatens polar bear populations: a stochastic demographic
analysis." Ecology 91.10 (2010): 2883-2897.
Durner, George M., et al. "Predicting 21st‐century polar bear habitat distribution from global climate
models." Ecological Monographs 79.1 (2009): 25-58.
Amstrup, Steven C., and D. P. DeMaster. "Polar bear, Ursus maritimus." Wild mammals of North
America: biology, management, and conservation 2 (2003): 587-610.

 

 

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