I have decided to write this paper on polar bears because they have unique adaptations to help them survive in the cold wasteland that is the Arctic Circle. They are not just found in the Arctic, however, they can also be found in parts of Canada, Alaska, Russia, Greenland and Norway. Polar bears are adapted for very cold climates which is why they live in some of the most frigid and remote areas on the planet. (Polar Bears Live) Some of the adaptations polar bears possess include lots of body fat to stay warm, unique fur for camouflage and to deflect sunlight. Polar bears are the largest breed of bear on the planet. (Polar Bears Live) believes that the polar bear evolved from a common brown bear ancestor maybe 6 million years ago. Science isn’t completely sure when or why they evolved to live in those areas but it can identify the unique skills of a polar bear.

 

            The adaptation of two layers of fur and large amounts of body fat are coupled together to help the bears maintain a constant body temperature of 98.6 degrees which is average for a mammal. They can maintain this temperature through outer conditions of -50 to -34 degrees throughout their lifetime. They can also maintain a constant heartrate despite the temperature changes despite seasons or the changes between day and night. Polar bear fur is not actually white like they appear to be. They are actually transparent, pigment-free shafts that are hollow. This is important because it allows the individual hairs to scatter light which helps keep the polar bear cooler. This is also great for camouflage because their fur reacts to light in similar ways to how the snow reflects the same light. They also move slowly and methodically to help conserve their energy.

 

            Polar bear feet are unique because they are 12 inches across and help distribute the bears’ weight evenly for when they walk on thin or extra slick ice. Polar bears also compensate for extra thin ice by spreading their legs farther apart and lowering their bodies to the ice. Despite being such large animals, these bears are experts at placing their feet carefully and quietly to stalk their prey. The black pads are textured to help grip snow and ice. These little bumps are known as papillae. On top of having the papillae to grip ice, they also use their 2 inch claws to grip in.

 

            The diet of a polar bear is mainly ringed seals. They wait by openings in the ice for the seals to come up for air. Rather than chasing the seals they wait for prey to come to them. Seals dig up to 6 feet through ice to create 10 to 15 air pockets. These are where the polar bears sit and weight. The bears use their powerful sense of smell to find the breathing holes and lay there from days to hours. This takes a lot of patience because there’s no actual guarantee the seals will show up. In summers, the bears eat for 20-30 minutes then swim for about 15 to wash. Similar to cats, they like their paws, muzzles and chests. They dry themselves off like dogs by shaking their fur and rubbing off on the snow. In the winter, they mainly dry off in the snow.

 

            These bears mate on sea ice from April to June but fertile eggs don’t implant until the fall. This is a process called delayed implantation. Newborns can be a foot long when they’re born and weigh about a pound. The bear family will stay in the maternity den for a few months until about April. They do this so the cubs can become strong enough to be able to survive the landscape they live in. For at least a year and half the cubs feed on the mothers’ milk. The mothers’ hunting skills are vital for the cubs’ survival because the cubs learn by watching her hunt.

 

            Polar bears do not hibernate like brown and black bears with the exception of pregnant females. Males and non-pregnant females remain active all year. Pregnant bears dig dens to give birth and stay there for 3 months before coming back out. The also den in the fall after feeding in August and September. Dens are found in snow drifts along the coast and rivers. A female can have 1 to 3 cubs in November or December. Twins are fairly common for these animals.

 

            For the next part, I want to talk about how climate change is effecting polar bear populations. Polar bears hunt and mate on sea ice but when the climate gets too warm, this ice melts. When this ice melts, food and mating are at risk which will put the whole population at risk. In the summer with no ice floes to help them hunt, polar bears are being forced to remain on land where they cannot hunt the seals. This has meant that they’ve gone longer periods of time without eating. Seal hunting season for the bears has been cut short nearly three weeks. Since they haven’t been able to hunt as long, average bear weight has decreased 15%. The Hudson Bay polar bear population has dropped about 20% due to these conditions. As the globe warms up, sea ice is retreating and becoming scarcer for the polar bears. This causes a couple different things; the waves are becoming larger and rougher which in turn not only makes the bear swim farther but also it’s a much riskier swim to make. In 2004, it was discovered that the polar bears who attempted these swims were drowning because it was so far and so dangerous that they couldn’t make it. The lack of food could also be resulting in cannibalism but it isn’t known for sure since males kill for mating rights of the females. (Global Warming)

 

            Another effect of global warming and climate change involves migration. As temperatures rise and ice caps melt, polar bears are getting farther and farther inland. When they come into contact with other animals competing and mating can occur. This has already started with polar bears now mating with grizzly bears to create the Grolar bear. Science has discovered that Grolar bears are fertile which means they could carry on and potentially could be a successful new species. The concern is that these hybrids are not adapting, they’re just breeding. The species as a whole would need to adapt to the melting ice caps to survive but at the rate it’s going, scientists fear there may not be enough time to do so.

 

            In conclusion polar bears are struggling. Global warming and the progressive changing of our climate is causing some serious health issues for these bears resulting in reproductive problems and problems with hunting and maintaining body fat. The loss of ice caps are creating longer swimming distance for the polar bears along with harsher ocean conditions that the bears aren’t always able to survive. Hunting season for them has been cut by nearly a month which has resulted in a drastic loss of body fat. Reproduction has declined due to unstable conditions for the babies and mothers. These polar bears are being forced to remain on land longer than they normally would which has caused the introduction of grizzly bears and other species. This has led to the cross-breeding of grizzlies with the polar bears to create the grolar bear. This is not adaptation at all and the result of this could lead to the loss of pure polar bear genes and ultimately the loss of that species. The grolar bear could live on and potentially survive better but its ancestor, the polar bear, might not have enough time to evolve to survive the new elements of its habitat. Global warming has sped up natural evolution and is threatening the lives of the polar bears. In just one generation, we could see the disappearance of polar bears if nothing can be done to save them. We’ve already lost 20% of the population since 2010, it will only take a few more years like this one to really hurt these bears.

 

Citations

1. Where Do Polar Bears Live? (n.d.). Retrieved April 05, 2016, from http://www.polarbearsinternational.org/polar-bear-facts-information/where-do-polar-bears-live

2. Global Warming and Polar Bears - National Wildlife Federation. (n.d.). Retrieved April 06, 2016, from http://www.nwf.org/Wildlife/Threats-to-Wildlife/Global-Warming/Effects-on-Wildlife-and-Habitat/Polar-Bears.aspx

3. Barcott, B. (2010, December 15). Grolar Bears and Narlugas: Rise of the Arctic Hybrids | OnEarth Magazine. Retrieved April 07, 2016, from http://archive.onearth.org/article/grolar-bears-and-narlugas-rise-of-the-arctic-hybrids

4. Photo from: https://www.pinterest.com/pin/519602875740067457/