Last week I did a webinar on the Hudson Bay Polar Bears. Here is the list of questions we received from the audience, and my answers. Each question could deserve much more information, but I tried to keep things fairly simple. Feel free to ask follow up questions in the comment section! Firstly, here is a recorded version of the webinar.
Are pizzlies / grolars able to reproduce? Yes, despite grizzly and polar bears being separate species, their hybrid offspring are viable, meaning they can reproduce.
I’ve been to Churchill for Northern lights and loved it with you. Is there a time when Belugas and Polar bears are there at the same time? Yes during the summer and early fall polar bears and belugas are both present in the Churchill River, however, when the great numbers of polar bears are present in October/November, belugas are very rare and we can only view them from shore. In 15 my years of fall polar bear seasons, I only saw belugas from a distance a few times. When the belugas congregate in the Churchill River polar bears are present, but in very low numbers.
How many females were in the video of the female protecting her cubs beside the snow buggy? I cannot remember, but the bears the female was charging were males.
Why do the male bears try to kill the cubs? is it a genetic dominance issue? All bears will kill smaller bears for food. A male bear doesn’t know who’s cub is his own, since females can mate with many males, and the cubs of a litter can have different fathers. The bear would have to be able to smell his own DNA which is unlikely.
Can the bears be enticed to hunt other things since there is less pack ice to hunt seals? The metabolism of polar bears is such they must have seals, with massive fat calories to be able to sustain themselves. The only alternative to seals are dead beluga whales. The are not fast enough to catch healthy caribou, and all other food sources in the Arctic are not abundant enough to sustain healthy populations.
Where do the seals go when there is not much sea ice? Do they travel further north, beyond where the polar bears would be able to go? Seals will be anywhere where there are fish and or crustaceans and shellfish for them feed, even during the summer when there is no ice, but without ice, it is very difficult for them to catch them unless are stranded in a low tide. It is possible, though very rare, for polar bears to be able to catch seals that are sleeping on rocks.
If a male kills a baby, does he eat it? Yes, male or female bears will consume bears
that they kill, or find already dead.
With climate warming, do you foresee the Churchill trips for polar bears extending into November? Our normal seasons do extend to late November, as they always have. Despite climate change, early freeze-ups are common, so the risk is too great to extend the season any further.
I observed lots of broken teeth on the bears, is there any significant disadvantage of broken canine teeth? Yes, broken canines decrease the ability for a bear to quickly kill a seal with a bite to the back of the neck, but broken teeth are common and bears with this condition can still make a living.
Are there any internet resources to help predict onset of winter ice in Churchill (ie trying to predict best polar bear sightings? Climate agencies such as NOAA and the Canadian Weather Service do attempt to predict winter severity by looking at forecasted ocean current patterns, such as El Nino and La Nina, but I wouldn’t make decisions based on these. Even mild winters can have early freezeups, and vice versa.
Are polar bears adapting to climate change and if so how? It will be basically impossible for polar bears to survive without ice. If climate change was much slower, polar bears may evolve back to a similar form as their grizzly ancestors, but they would no longer be polar bears. Polar are so specialized to survive as ice hunters, without ice, it would be like fish adapting to live on land in a few decades.
As polar bear numbers have been steadily getting lower – have the seal numbers been going up? I am not sure about this because it depends on the region, and many confounding factors, such as human consumption of seals and seafood. In Hudson Bay the polar bear population dropped about 20% since the early 1980’s and has since stabilized. One would expect seal numbers to increase without this major predator in the future. Another factor to consider is that in a very warm spring, which did occur in the 1990s a few times, there was a total loss of seal reproduction because the baby seals need a solid layer of snow on top of the ice for their birthing layers.
How often does a male bear kill cubs? In my experience, not all male bears pursue cubs that are with mothers because this is a very difficult, dangerous and costly practice. Some male bears seem to be more aggressive to families than the average male. I am sure that nearly every male, or even a female, would catch a cub that was abandoned. In times of hunger, bears will be more aggressive to each other.
I keep seeing in my mind’s-eye a starving polar bear clinging to a small piece of ice, too exhausted to swim to land. It is very depressing. Is this really as bad as I think about the situation? This depends on where you are. In Hudson Bay, because of recent polar vortex activity that I explained in the webinar, Hudson Bay seems stable right now. It seems the most dire situation is in the Alaskan arctic, where warm air from the Pacific has cause a drastic decrease in permanent summer sea ice. The ice is now well north of the continental shelf, so the water is so deep under the ice, there are no fish for the seals to eat, so they don’t hang out there. When polar bears continue to search this far away ice, devoid of seals, they can burn through their fat resources, and then choose to make the very long swim back to shore, and can starve. Many bears just stay near shore during the summer now, and have much less opportunity to hunt than in the past.
When summer comes, bears go ashore, where do the seals go? The seals stay in the shallow ocean areas where they find fish. The presence of ice is needed for bears to hunt seals, but in the summer the seals are still there. Seals will sleep on rocky islands instead of on the ice.
Are the cubs in danger of being eaten, attacked by a male bear? Yes, all bear cubs are vulnerable to predation by adult bears. Mother bears are very good at protecting their cubs. An orphaned cub will certainly fall prey to a, adult male or female bear.
Do their claws continue to grow and if so, how are they trimmed as they live on the ice for a good amount of the year? Yes claws continue to grow, but get worn down through using them to grip ice, travel and hunt.
Brad showed the bottom of the polar bear’s paw with tufts of snow/ice in between the pads. When we do winter mountain hiking it drives our dogs crazy as they have thick fur and they need the mushers. How do the polar bears manage the ice in-between their pads that form in their hair. Normally the snow is dry and powdery and doesn’t seem to bother them like this. I have seen bears chewing snow from the paws when the snow is wet.
Is polar bear skin black? Yes the skin of all bears is black, except the skin under the pandas white fur is pink, and black under the black fur. Polar bear fur is translucent, and appears white due to the way it scatters light.
Generally, how long does a Polar Bear live in the wild? All bears generally live to around 30. Female bears live about 5 or more years longer on average than males, likely due to body damage due to mating season fights. Polar bears seem to live less than brown/grizzlies, and most dont make it into their 20’s. The oldest known polar bear in the wild lived to 32. Polar bears in captivity have lived into their late 30’s, and other captive bear species have lived into their 40’s.
What’s up with summer polar bears hunting beluga whales? There was a sequence recorded by BBC of a polar bear killing a young Beluga in the Seal River north of Churchill during the summer. This is a very rare occurrence, and this cant save population of polar bears that we have now, as the success rate of bears catching young whales is very low, and limited to only a few river mouths. There have also been a few reports in history of polar bears killing belugas off the coast of Alaska, but this is extremely rare. In the summer dead beluga whales wash ashore, possibly after being wounded by Nunavut Inuit whale hunters, and they do provide some bears with a fantastic food source.
Don’t they use a lot of energy sparring in fall during a time when they need to conserve energy? They won’t chase a snow goose for more than 11 seconds, but the sparring seems to take more energy. Sparring is very important for males to hone their fighting skills which are needed to successfully compete for females during the late winter mating season. It seems the bears who spend the energy practicing do much better passing on their genes than aloof bears.
Do all the tours from so many companies bother the bears and stress them? There have been observational studies that have shown the vehicles in the viewing area have basically no impact on bear behavior and numbers. The bears quickly become accustomed to the vehicles, which are very careful as to not disturb them. The vehicles can only travel on old military trails, so bears always feel like enough space, and dont feel pressured. Often, the bears appear curious and investigate the bear viewing vehicles.
Can they eat their dead rivals? Yes bears will eat each other. For them, meat is meat. It is rare for bears to kill each other, however.
Do they recognize their cubs in later years? When you consider the incredible intelligence level and memory of polar bears, and the intimate bond between a mother and her cubs before being weaned, I am sure they recognize and remember each other, but there is no bond in later years. After the first few years with mom, it is every bear for himself.
How can they breathe when they take a nap and allow the snow to cover them up during a blizzard? Oxygen easily passes through snow.
I read that there were some problems with bears coming in to Churchill and attacking people – is that still an issue? There have been very very few bear attacks in Churchill. On Halloween 2013 there was an incident where an old, unhealthy male encountered some people in the predawn hours and two people were seriously injured, but not killed. In my opinion most bears respect people, and dont look at them as prey, and the town goes to extreme measures to keep people safe. Churchill has a special team of conservation officers who are dedicated to dealing with bears in town.
What predators do polar bears have? The only real predators to polar bears are humans and other polar bears. Wolves could take very weak, or very young bears. There was a polar bear jawbone found in the stomach of a Greenland Shark in the European arctic in 2008, but no-one can be sure that the shark killed the bear, but it is a possibility. It is also possible that orcas could attack polar bears, but I have never heard of this reported. Orcas have, with climate change, expanded their ranges into polar bear habitat.
Polar Bears are mostly sea hunters now…but with their gene connection to the Brown Bear…can that help them adapt as climate change makes sea hunting harder and harder or will it take too much evolutional time to occur? They would have to evolve an entirely different body type to survive on land, and climate change is happening too fast. Even they were able to revert back to a brown bear lifestyle, they wouldn’t be polar bears anymore.
With the world sheltering in place, has this had a impact on the ice flow? I havent heard of, or can think of any way the pandemic has changed sea ice conditions. If there are no more cruise ships in the arctic, it would have some impact I imagine, as the boats sometimes have to break ice. The carbon footprint of humans has been vastly decreased in the last few months, but this is only temporary.
Are the churchill town’s people on lockdown during the weeks the bears come to town? People of Churchill practice extreme caution during bear season, but it remains a very busy town. Churchill has a special team of conservation officers who are dedicated to dealing with bears in town.
What’s the range of how many people are attending these webinars? The audience is normally between 500 and 1000 people.
Is there a web site where you can track polar bears with live data? There is a live cam coming from Churchill during polar bear season. WWF and the Canadian Wildlife Service occasionally release data of collared polar bear locations and movements, but not live. You can visit WWF polar bear tracker to see recent locations from collared polar bears.
When I was in Churchill with NatHab one of the guides told us that it is very difficult to collar polar bears because of the shape of their neck. Have they found an easier way (a better collar) for them now? Because of the tapered neck of male polar bears, they cannot be collared, but females can, as their head is broader than their neck. WWF is constantly redesigning tracking devices to begin using a glue-on style on the back of the neck, which could be used on males.
Is it better to go on a polar bear trip earlier or later in the fall trip season? Late season has a better chance for snow and cold temperatures and more bears, but there is always a risk that ice will develop and the bears leave. Some years the first and second weeks of the season are the best, sometimes the last trips are the best. It is impossible to predict.
At what point does the fight end – after one is killed? Bears are very hard to kill. Normally one of the bears will give up before there is too much damage.
So what is the best month for viewing polar bear excursions in Churchhill? Mid October-late November.
Do they only eat seals, or also fish? A polar bear will eat any meat it can find, including fish, but polar bears cannot swim fast enough to catch fish in the water. They have been seen catching spawning arctic char in some rivers in the summer, much like brown bears catch spawning salmon.
When do the polar bear cubs get weaned and start eating seals? Hudson Bay bears wean their cubs at 2.5 years, and high arctic bears keep them an extra year (3.5 years).
How long is the gestation period? Polar bears mate in March, and have their cubs around Christmas, but the fertilized eggs do not implant and begin to develop until October, if and only if she has enough fat to sustain a pregnancy. This is called “delayed implantation.
How does Mom make the cubs leave, or is it instinctive for the cubs? The females of all bears must force the cubs to leave, as they would love to stay with her. This change in mood is hormonal as mating season approaches in late winter.
Is it more rare to see a male or a female polar bear in the wild? There is an equal number of males and females, so there is no difference.
Why would an adult male kill a juvenile female, a potential mating partner? This is rare, but hunger is king when it is not mating season.
How much time do they spend on the sea ice in Winter? Bears stay on the ice as long as it is present. Ice begins to develop in November, and lasts until July in Hudson Bay.
When do they hibernate? Only pregnant female polar bears shelter in a den from October-late Feb/March, and then they head to the sea ice with their cubs to hunt seals.
Several pictures showed birds, while bears were feeding on seals; bears dont try to eat the birds? The birds are too fast, but a polar bear will eat anything it can catch.
Is it true that the polar bear’s hair is transluscent and not white? Yes, polar bear fur is translucent, and appears white due to the way it scatters light. As the bears age, the hollow hairs turn a but yellowish because of oxidation. Only young cubs are pure white.
Are Kodiak bears, brown bear, grizzlies and polar bears closely related? Kodiak, grizzlies and brown bears are all the same species. Kodiak is a different subspecies because they were isolated for so long. In North America we call grizzlies which live in coastal areas of British Columbia and Alaska coastal brown bears. Polar bears split apart from brown bears, but still remain close enough genetically that they can have their fertile hybrid offspring.