As seen in the latest issue of World of Animals, we spoke to Alysa McCall from Polar Bears International. Read the full interview here.
What is your role at PBI?
As the Director of Conservation Outreach and Staff Scientist, I get to be involved in a fun and rewarding mix of education and science. I help develop outreach for many of our programs including our Tundra Connections series where we hold live webcasts to connect scientists in the field with viewers around the world, and our live Polar Bear Cams that allow stream footage of polar bears during the fall migration in Churchill, Manitoba, thanks to our partners explore.org and Frontiers North Adventures. In addition to conservation outreach, I work on multiple Hudson Bay polar bear studies and regularly communicate with scientists to get the latest polar bear and climate information to the public.
How are polar bears adapted to survive in the Arctic?
Polar bears evolved from brown bears to fill a very specialized niche: Arctic sea ice. Polar bears make their living walking thousands of kilometres on sea ice each season to find and hunt their main prey, seals. Over many thousands of years, polar bears developed incredible adaptations that allow them to be the top predator at the top of the world. Some polar bear subpopulations spend part of their year on the Arctic tundra when sea ice is not available, but these bears do not have special adaptations for living on land compared to bears that live on ice year-round.
While polar bears will eat a variety of foods, their main prey and most important food is seal- more specifically, seal fat. About 90 per cent of all fat that polar bears consume goes directly onto their own body, an amazing conversion rate that helps them store enough fat for times when food is scarce. In the spring, they enter a phase called hyperphagia, which coincides with when seal pups are naive and abundant, where they eat an immense amount of seal fat in a short period of time, building up their own fat stores for the lean summer months ahead. In Hudson Bay during the summer, polar bears must wait for four months (pregnant females wait up to eight months!) before their next real meal. Though they will snack on eggs, kelp, and berries while on land, none of these food sources contain enough calories or fat to sustain polar bears for long. This is why it is so critical that polar bears have enough time and enough sea ice to hunt seals and build up body fat; without enough fat stores, polar bears could starve when sea ice isn’t available.
Luckily, polar bears have other adaptations to help them hunt seals and stay comfortable in the cold. Their fur consists of a dense, insulating underfur topped by guard hairs of various lengths. Each hair shaft is pigment–free and transparent with a hollow core making them appear white and giving them camouflage against the ice. Their fur and body fat (up to 11.5 centimetres [4.5 inches] thick) provide polar bears with excellent insulation; their body temperature and metabolic rate won’t change even when temperatures reach -37 degrees Celsius [-34.6 degrees Fahrenheit]. In fact, a polar bear can overheat quickly when temperatures get much above 10 degrees Celsius [50 degrees Fahrenheit] in the summer. Compact ears and a small tail also help prevent heat loss.
Polar bear paws (up to 31 centimetres [12.2 inches] across) help distribute weight when treading on thin ice and act like large paddles when swimming. Black footpads on the bottom of each paw are covered by small, soft bumps known as papillae, which grip the ice and keep the bears from slipping. Polar bear claws are thick and curved, sharp and strong. Each can measure more than five centimetres [two inches] long and are used to provide traction on the ice, and to catch and hold prey. A polar bear’s cheek teeth are sharp so they can shear off chunks of fat and meat. Their canine teeth are long, sharp, and widely spaced so they can seize and hold seals, and pull them out through holes in the ice.
Maybe above all, the patience and intelligence of these bears keeps them always curious and on the move, and ready to do what it takes for their next meal.
What threats do they currently face?
The biggest threat to polar bears as a whole is loss of sea ice habitat due to climate change. Losing sea ice impacts their ability to hunt, travel, and even reproduce, leading to smaller and less healthy bears, and eventually reduced populations. Other threats to polar bears, which vary in intensity throughout the 19 sub-populations, include harvest management, pollution, increased industrial activity, and a growing number of negative human-bear conflicts. All of these issues are intensified when more polar bears spend longer times onshore—another impact of sea ice loss.
How does habitat loss affect polar bears?
Polar bears depend on sea ice as a platform to hunt seals, to travel, and for aspects of reproduction. Polar bears have adapted to this marine environment and cannot make their living on land full-time. In certain areas, loss of sea ice has been tied to decreased population size, lower body weights, and decreased reproduction.
With any animal, loss of habitat is a major conservation concern. With polar bears, loss of their habitat may be especially concerning because of the difficulty in mitigating the loss. For other wildlife species, we may be able to build protective fences, or plant more trees, or even post guards for protection. Unfortunately, no fence can prevent sea ice from melting. We need to take preventative action, and research shows that preventative action will work.
Greenhouse gasses act like a blanket around earth that trap heat in our atmosphere. As we burn fossil fuels for energy, the emissions we emit thicken this blanket and our atmosphere gets too warm, too quickly. As conditions heat up, sea ice melts and the entire Arctic ecosystem, including polar bears, is impacted. Research shows know that if we reduce our greenhouse emissions, sea ice will rebound within about a decade.
What work does PBI do to help conserve polar bears and their environment?
Polar Bears International is the only conservation organization whose sole passion and focus is on polar bears. Through media, science, and advocacy, we work to inspire people to care about the Arctic, the threats to its future, and the connection between this remote region and our global climate.
By supporting and conducting polar bear research throughout the Arctic, educating people about polar bears and climate change, providing resources to help anyone take action, and by networking with change makers across the globe, we will help secure a future for polar bears, and for people.
What research projects are you currently involved in?
Right now we are supporting different polar bear research projects throughout Canada and the US, but are also leading our own. A few of the studies that PBI is directly involved with right now include:
The Maternal Den Study
Understanding polar bear denning behaviour is critically important as human activities increase and more industry moves into the Arctic. This long-term research project gathers baseline information on polar bear behaviour at den sites in Alaska, including how long families remain in the area after emerging in the spring. The project is also helping to refine den detection techniques. The knowledge gained will help set guidelines so mothers and cubs aren’t disturbed and will help us understand the impacts of climate change on the critical reproductive function of denning.
Southern Hudson Bay Research
This collaborative study is gathering additional information on polar bears from the southernmost part of the Southern Hudson Bay population in James Bay. It follows on earlier work that suggests these bears may be somewhat genetically distinct from other SH bears—and might, therefore, merit consideration as a separate management unit. The study is identifying their movement patterns, including the selection of maternity denning sites. It will contribute to our knowledge of the broader Hudson Bay meta-population and system.
Sea ice losses from climate change have dramatically altered the polar bear’s access to its primary prey in some regions. Because nutritional stress can influence reproductivesuccess and survival, identifying ways to measure stress can help scientists and managers monitor the health of individual bears and the effect of sea ice losses on polar bear populations. One way to do this is by studying the levels of cortisol, a blood-borne stress hormone, in samples of polar bear urine, blood, or hair. Our cortisol studies include work with both polar bears in captivity and in the wild.
Photogrammetry Analysis of Polar Bear Images
This is a pilot effort to develop tools to gather information on the condition of polar bears using a combination of visual assessment and digital photographic measurements. Western Hudson Bay is the perfect place to test new methods due to the long-term data on bears in the region. If successful, this project will help scientists obtain non-invasive baseline condition data on bears in areas that currently lack any formal monitoring.
What can people do to help protect polar bears and their habitat?
Anything you can do to reduce greenhouse gas emissions in your home and community will help polar bears, and people too. All the individual actions you are already doing are great, but it’s time now that we work together on a larger scale to make sure that we are protecting this planet for future generations of all creatures. Whether you are involved in a community ride share, are using green energy in your home, or are voting for leaders that care about the environment, you are helping your family as well as polar bear families. We can all make a difference!
You can also follow PBI for ways to help. You can sign our Petition for Polar Bears, take the challenges in our Save Our Sea Ice campaign, or even adopt a polar bear!
To learn more about polar bears and PBI’s conservation efforts, visit their website at http://www.polarbearsinternational.org/