Species profile: Polar bear

Hello again, welcome back to animals under threat. Today, we will be covering the largest carnivore in the arctic circle and is considered to be the largest bear species to be alive currently. This species of bear is under threat from loss of sea ice due to global warming, pollution, and human interaction. Give a warm welcome to the Polar bear (Ursus maritimus).

Polar bears are characterized by their white fur, long neck, small head, rounded ears and short tail. Male polar bears are larger than the females as they can weigh up to 410-720 kg or 900-1,600 pounds. Sometimes nicknamed the sea/ice bear, polar bears live throughout the arctic region and travel across ice floes to search for seals. It has not natural predators or rival species and has no fear of humans (Britannica.com, 2019).

diagram by https://www.britannica.com/animal/polar-bear 

Polar bears have adapted to their arctic home with unique adaptions. They have a thick coat of fur which covers a layer of fat that keeps the bear warm. The bear’s fur also grows over their paws which helps protect them against cold surfaces and help the bear’s grip on the ice. Polar bears have black skin under their white fur which absorb the sun’s rays to help keep the bear warm (Nationalgeographic.com, 2019). Polar bears can swim up to a pace of six miles per hour by paddling their front legs and using their back legs as a rudder (Worldwildlife.org, 2019).

polar bear's fur and skin by Jon Aars / Norwegian Polar Institute / WWF-Canon

Female polar bear reaches mature age between 4-5 years old and can start breeding. Pregnant polar bears enter a den that is usually located in a snow drift or slopes in order to give birth. Usually twin cubs are born although there have been cases where only one cub is born or triplets. The cubs feed on their mother milk while the mother fast until she is ready to open the den. They stay near the den as the cubs learn to walk and play while the mother feeds on the vegetation that is around the den. The mother will then lead her cubs out to the sea ice to hunt seals as the cubs observe their mother’s hunting. There has been rare case of cubs that have been adopted by other female polar bears after they have been abandoned. The mother will look after her cubs for 2 and half years leaving them to survive on their own (Wiig et al, 2015).

                                                                         polar and cub by AWeith

As polar bear has no fear of humans, they enter human settlements to find food and exploring the area. This has led to conflict between humans and polar bears as polar bears are shot and killed by humans defending their homes and food (Wilder et al, 2017). Due to the increase in global warming, the sea ice that the bears depend is decreasing which makes it harder from the bears to hunt and have to swim longer leading to drowning. With pollution from human settlement such as plastic bags been found in polar bear stomach leading to death of the animal due to eating the plastic (Regehr et al, 2016).


Next time, we will be covering a species of sea snake that has an unusual name.


References

https://www.britannica.com/animal/polar-bear retrieved 21/12/19

https://www.nationalgeographic.com/animals/mammals/p/polar-bear/ retrieved 21/12/19



Regehr, E.V., Laidre, K.L., Akçakaya, H.R., Amstrup, S.C., Atwood, T.C., Lunn, N.J., Obbard, M., Stern, H., Thiemann, G.W. & Wiig, Ø. 2016, "Conservation status of polar bears (Ursus maritimus) in relation to projected sea-ice declines", Biology letters, vol. 12, no. 12, pp. 20160556.



https://www.worldwildlife.org/species/polar-bear retrieved 21/12/19



Wiig, Ø., Amstrup, S., Atwood, T., Laidre, K., Lunn, N., Obbard, M., Regehr, E. & Thiemann, G. 2015. Ursus maritimus . The IUCN Red List of Threatened Species 2015



Wilder, J.M., Vongraven, D., Atwood, T., Hansen, B., Jessen, A., Kochnev, A., York, G., Vallender, R., Hedman, D. & Gibbons, M. 2017, "Polar bear attacks on humans: Implications of a changing climate", Wildlife Society Bulletin, vol. 41, no. 3, pp. 537-547.



picture references

polar bear skin by Jon Aars / Norwegian Polar Institute / WWF-Canon

polar and cub by By AWeith