Arctic Animals and Climate Change
(italic text by Jim Halfpenny; print text by Betty; photos by Jim Halfpenny unless noted)
Remember this image I posted on Christmas Day?
Photo by Betty
Images like this one are quite common; scenarios that depict polar bears and penguins living together. I have had numerous people ask me if I’ve seen a polar bear yet in Antarctica. It’s a very common mistake. Jim Halfpenny has spent 23 years studying polar bears in the Arctic. He can give us first-hand information on polar bears and other critters of the Arctic, and lend some insight into what’s happening to their habitat due to changes in the climate. Read on to find out more…
Each polar region has animals specific to it. The warm tropical regions keep these animals isolated at their respective end of the earth; north or south. For example, penguins are only found in the southern hemisphere and mostly around the coastal areas of Antarctica. Mammals of the north include polar bears, Arctic fox and Arctic hares.
We see and study these animals on our educational trips to the north. All these mammals have some basic characteristics in common. First is their ability to live in the cold. All have thick fur insulation to protect them from the cold. Polar bears also store fat both for insulation and a food resource.
The Arctic fox and hare may both be brown in the summer. Brown fur helps them hide in vegetation during the summer and white fur helps them hide against the snow in the winter. However the body requires energy to change from white to brown to white fur each year. Since food is scarce in the far north, the Arctic hare does not have enough energy to make the changes twice each year. Thus in the farthest north area Arctic hare stay white even in the summer.
In the far north three key birds are the snowy owl, gyre falcon, and ptarmigan. All can be white with the owl and ptarmigan changing color between seasons. White gyre falcons are white all year long. Of course, the important birds of the south are the penguins.
The snowy owl…
POLES: Together and Apart – The Polar Bear
Polar bears are an important symbol of the Arctic. A large male polar bear may weigh over 1600 pounds while females may weigh over 600 pounds.
Polar bears spend a portion of each year on shore. When on shore they are social and may congregate together. While together they often playfully wrestle with each other. Wrestling teaches bears to judge the size and strength of other bears. Smaller bears learn that they should not fight with larger bears for either food or mates. Smaller bears can then go safely to another spot to hunt for food and wait until the next year when they are bigger to find a mate.
The bears depend on cold and ice to survive. Unlike grizzly and black bears, polar bears do not hibernate but hunt for food in the winter. Polar bears feed mainly on seals.
When sea ice covers the ocean, seal must keep a holes open through the ice so they can breathe. Polar bears wait by the holes to capture seals for food. Each winter polar bears eat many seals and get very fat. At the end of the winter, 40% of the weight of the polar bear may be fat from eating seals.
When the sea ice melts in the summer, polar bears must come ashore. While on shore, polar bears cannot catch seals and must live off their stored body fat. Along the shores of Hudson Bay where I work, the bears may be on shore from four to six months without eating. If for some reason they cannot get back out on the sea ice, there is a substantial chance they will starve.
Now the Arctic is quickly becoming warmer, a process called Polar amplification. Polar amplification means that a little warming has more dramatic effects on temperatures than the same amount of warming in temperate or tropical regions. Polar amplification creates significant melting of the sea ice and glaciers. I have worked in northern and southern polar regions for nearly 50 years now and have personally seen that the ice is melting much faster each year.
With warmer temperatures, the sea ice is melting faster than even and the polar bears must come ashore sooner each spring and wait later each fall for the ocean to freeze over again. With longer time ashore, the bears are using more of their body fat and some who do not have enough are starving.
Since 1990 when I first started studying polar bears near Churchill, Canada the population has decreased 22%. Survival of the cubs born each year is very low and becoming poorer each year.
This is because mother bears cannot produce as much milk to feed their young. For each week a mother polar bear must come ashore early, she average 22 lbs lighter. Along the shores of Hudson Bay, bears are having to come ashore as much as 4 to 6 weeks earlier.
For example, if a mother comes ashore 5 weeks earlier, she may be 110 lbs lighter (5 weeks x 22 lbs per week). With that much less fat she cannot produce as much milk as she used to and the cubs get less to eat. If there is a smaller cub in her litter, the smaller cub is less likely to survive.
Polar bears are in great danger due to climate change causing warming in the northern regions. Over the next few decades there will be many fewer bears than there are today and I have to worry about the fate of the bears by the year 2100 as climate warming in the north continues.
There are more land mammals in the Arctic region including caribou, fox, brown bears, muskox, reindeer (same genus as caribou, Rangifer, but some differences in the two animals; reindeer are found in Europe and Asia and can be wild or domesticated); marmot, muskrat, vole, Arctic ground squirrel, lemming, wolverine, and wolves. Changes in climate will likely have an effect on all of these mammals in some way or another.
Marine (ocean) mammals in the Arctic include walruses, different species of seals and dolphins, and several types of whales, including the narwhal (a medium-sized toothed whale).
The ocean surrounding Antarctica also has marine mammals such as whales, seals, and dolphins. Remember, there are no land mammals in Antarctica. I will not be seeing polar bears here! One of these days though, I hope to travel with Jim to the Arctic to witness first hand these beautiful creatures.