WildFact
›
Information Section
›
Terrestrial Wild Animals
›
Carnivorous and Omnivores Animals, Excluding Felids
›
Bears
Polar Bears - Data, Pictures and Videos
Polar Bears - Data, Pictures and Videos
|
Polar Bears - Data, Pictures and Videos
|
Question from Ruth: Do polar bears swim?
Answer by Dr. Thea Bechshoft Polar bears are experts at doggie paddle swimming: they use their front paws to paddle with while their hind legs trail behind them. Data from satellite collars show that swims of an average of 100 km (62 miles) over 3 days are not unusual. However, the most extreme polar bear swim that we know of was an adult female who swam for nine days straight, a total of 687 km (426 miles). Very impressive! However, it did cost her her cub and 22% of her body fat, meaning that although this swim was physically possible for her, it was a challenge. One of the consequences of climate change is that the Arctic sea ice gets more scattered. This means that the bears have to spend more of their valuable energy stores (body fat) on swimming to get from ice floe to ice floe as they wander the sea ice looking for seals. A bit of bonus info while we’re on the topic and because I get asked this quite often: polar bears can dive for at least 3 minutes. Also, they are strong but slow swimmers, not nearly fast or agile enough to be able to catch seals by hunting them in the water.
Question from Jonas: How can polar bears survive swimming in ice cold water when humans can't?
Answer by Dr. Thea Bechshoft The answer can be summed up in one wobbly little word: fat! Polar bears are exceptionally well adapted to the cold Arctic environment, and are able to stay toasty and keep up their 37° C body core temperature even when the snow storm is raging in the middle of the polar night. What keeps the bear from freezing when it’s above water is it’s fur – but when it’s under water, the hair no longer offers much isolation and the bear must instead rely on the fat layer it has accumulated under its skin to stay warm. This fat layer can be up to 11 cm thick, and is especially prominent on the back haunches (rump). How thick this layer becomes obviously depends on how successful of a hunter the individual bear is – the more seals, the fatter the bear. And as I’ve said before, a fat polar bear is a happy polar bear! On a side note, a good layer of fat also helps keep the bear naturally buoyant in the water. Polar bears are very good swimmers, and long distance swims are common in adults that roam the ice alone. Females with cubs on the other hands tend to avoid swimming too much if at all possible; the cubs are not yet very well isolated, and may ultimately die if they are too cold for too long as would happen during a lengthy swim. Some polar bear mothers solve this by giving their cubs a piggyback ride when crossing the water between ice floes (as you can see an example of in the picture I’ve attached). The most extreme polar bear swim on record is that of an adult female who swam for nine days straight, a total of 687 km. Very impressive! Unfortunately, it also cost her her cub and 22% of her body fat, which tells you that although this swim was physically possible for her, it was not without cost. Humans on the other hand are very poorly insulated (even when you may feel that your bathroom scale is trying to tell you something else!). Compared to polar bears we have almost no fat layer under our skin, which is the main reason we don’t last very long in cold water. Some long-distance swimmers cover themselves in grease before an extensive open-water swim (e.g. lanolin, petrolatum, lard), partly to protect themselves against the cold, partly to protect themselves against jellyfish stings. 
Some data from the study "To weigh or not to weigh: conditions for the estimation of body mass by morphometry" et.al. Cattet and Obbard 2004:
More than not in this study, these bears aren't full grown adults (most of the average comprises of subadults), but it should give an idea of the average girths and lengths relative to average age of polar bears in the Hudson Bay. One thing the study has wrong (and @
 (04-18-2018, 04:47 AM)Polar Wrote: More than not in this study, these bears aren't full grown adults (most of the average comprises of subadults), but it should give an idea of the average girths and lengths relative to average age of polar bears in the Hudson Bay. One thing the study has wrong (and @ Somewhere within the bear section here is a chart showing the measurements of captured Yellowstone grizzlies during a study. The weight of the "average male" was given as ( best I can remember ) roughly 420 pounds. However, I wrote down the weights of only those from ages 9 and above, averaged them, and found that the average male Yellowstone grizzly weighed 500 pounds - big difference.  (12-28-2016, 01:12 PM)Polar Wrote: Polar bears with shoulder humps: Those aren't shoulder humps. What you see there is a combination of the scapula position, the length and position of the neck and the fur. You can see that effect in big cats too. 
Here is an interesting document on polar bear predation on belugas and narwhals
http://pubs.aina.ucalgary.ca/arctic/Arctic43-2-99.pdf
Scavenging dolphin carcass.
 *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author
Heart Break
 This is what climate change looks like. This starving polar bear was spotted by National Geographic photographer Paul Nicklen on Somerset Island.As temperatures rise, and sea ice melts, polar bears lose access to the main staple of their diet—seals. Starving, and running out of energy, they are forced to wander into human settlements for any source of food. Feeding polar bears is illegal. Without finding another source of food, this bear likely only had a few more hours to live.
https://www.psychologytoday.com/us/blog/...ng-extinct
Lions and Tigers and Bears Are Going Extinct Meanwhile, our minds get tricked into thinking these animals are safe. Posted Apr 18, 2018
News about problems with polar bears from Russia. Pity to read about this kind of happenings :/
https://edition.cnn.com/2019/02/11/asia/...index.html   *This image is copyright of its original author 52 bears sighted around Belushya Guba, the biggest settlement on Novaya Zemlya Russia is battling an unprecedented invasion of polar bears on a remote Arctic archipelago that is home to the country’s most northerly military base. Known locally as “Lords of the Arctic”, the wild animals have been terrorising the population on Novaya Zemlya, a group of mountainous islands off Russia’s northern coast once used as a testing ground for atomic bombs. “People are scared, afraid to leave their homes, daily routines are being broken, and parents are unwilling to let their children go to school and kindergartens,” according to Alexander Minaev, the deputy head of the local government in Novaya Zemlya. Global warming is melting Arctic ice, forcing polar bears to abandon their traditional habitat and move closer to human settlements in search of food. But hunting the unwelcome visitors is prohibited in Russia where polar bears are officially protected as an endangered species. The government in Russia’s Arkhangelsk region declared a state of emergency on Novaya Zemlya on Saturday citing an unprecedented build-up in the number of polar bears in the remote region since December last year. Some 52 bears have been sighted around Belushya Guba, the biggest settlement on the islands – or about one bear for every 10 members of the local population. Aggressive behaviour Most of the animals appear to have holed up in a disused military garrison, but some have ventured out to enter residential and public buildings and displayed “aggressive behaviour”. Army personnel have been trying to drive out the bears using non-lethal measures. But the polar bears are so “convinced of their own safety” they ignore barking dogs, bright lights and loud noises intended to scare them away, local officials said. Rosprirodnadzor, the Russian environmental watchdog, has so far refused permission to shoot the bears, but is sending a special commission to Novaya Zemlya to assess the problem. Local authorities are calling for drastic action and say a cull may be inevitable. Unprecedented Zhigansha Musin, the head of the Novaya Zemlya administration, said the number of polar bears sighted was unprecedented. “I have been on Novaya Zemlya since 1983 and there has never been such a mass invasion,” he said. “They have literally been chasing people.” Polar bears migrate from the south to the north of the Novaya Zemlya archipelago in response to seasonal changes in ice conditions, Ilya Mordvintsev, an ecological and evolution specialist at the Russian Academy of Sciences, told the Tass news agency. They were stopping off at Beyusha Guba to search for food in local dustbins. “If there was no alternative source of foot there, they would probably pass straight by” without stopping, he added. Polar bears are facing an increasing struggle to survive as global climate change warms the Arctic Oceans shrinking their natural habitat. The World Wildlife Fund estimates there are 22,000 polar bears left in the world and that their numbers could shrink by 30 per cent by 2050. Industrial developments in the Arctic where oil companies are exploring for new resources are also a threat to the species. https://www.irishtimes.com/news/world/europe/town-in-northern-russia-battling-invasion-of-polar-bears-1.3788910?mode=amp
Russian Region Declares Emergency After Polar Bears Terrorize Town
https://slate.com/technology/2019/02/rus...hange.html |
| Users browsing this thread: |
| 12 Guest(s) |