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Polar Bears - Data, Pictures and Videos
Polar Bears - Data, Pictures and Videos
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Polar Bears - Data, Pictures and Videos
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From the facebook page of Dr. Thea Bechshoft, A Polar bear expert and researcher , On her page she take and answer on any question related to polar bear. Below is a question asked by Geoffrey.
Question from Geoffrey: "Do polar bears hibernate and if yes, how long? Does it depend on which area they live in? And will climate change be a problem?" Answer by Dr. Thea Bechshoft: Even though some bears hang out in old dens for brief periods during especially nasty snow storms, pregnant females are the only polar bears that hibernate. All other polar bears are active, hunting on the sea ice throughout the winter. While the other polar bears are out in the cold and dark of winter, the pregnant female will stay in her den, lowering her body temperature and heart rate. By lowering her metabolism, she can reduce the energy she needs to survive by an impressive 60%. As a pregnant female polar bear can be in her den for up to 8 months without eating or drinking being able to survive only by metabolizing her own body fat is an essential physiological ability. Especially since she is not just keeping herself alive off of her own bodily reserves, but must also convert the majority of her fat into milk for her cub(s). The female’s time in the den is generally made up of 2-4 months alone prior to giving birth, and 3-4 months together with her new-born cub(s), nursing. After leaving the den, the family head out towards the ice, looking for seals. There is a tendency for the more southern-living polar bears to enter and leave the den earlier than those living further north, but if I were to give an “average” it would be October-March (with variations of up to a month or so on either side of this time period). However, the timing of entering into or leaving the den also depends on many other factors – female body condition, female age and experience, weather, growth of the cub(s), snow accumulation, ice condition etc. - and so varies between individual females as well as between years. Climate change is likely to lead to a number of challenges for the pregnant and hibernating females. First of all, lack of sea ice ultimately leads to worse seal hunting conditions and thus thinner polar bears. A pregnant female in poor body condition is more likely to stay on the ice longer, hoping for extra seals - in other words, she is likely to enter the den at a later point in the year than a heavier female would. In addition, females in poorer body condition have smaller cubs and also have a tendency to leave the den earlier, which can be fatal to the cubs, if they are not yet grown and robust enough for the outside world. Another consequence of climate change is an increase in rain events in the Arctic. Rain changes the texture of snow, which could e.g. make it harder for the pregnant female to find a suitable spot to dig her den and/or cause the den to collapse as the snow roof gets saturated and heavy with rain. Finally, the changing sea ice conditions seem to be causing a shift in where the pregnant females are denning: in areas where they used to den on the ice, they now den on land and in areas where they used to den on land, they are now denning on the ice. Ongoing studies will tell us more about this particular change in the bears’ denning ecology in the years to come. The picture here shows a female polar bear with her two cubs at their den on the shore of Western Hudson Bay. The family group will often stay near the den for a week or two after their first emergence before finally heading out to the sea ice to look for seals.  *This image is copyright of its original author
Question from Anne-Sophie as well as Aslak & Katja:
I see stories in the media about how climate change and lack of ice won’t be a problem for the polar bears, as they are apparently able to survive on land by eating dolphins, bird eggs, and reindeer – is this really true? Answer by Dr. Thea Bechshoft: Good question, all three of you! Even though (certain sections of) the media like to believe that polar bears would do just fine without sea ice, these stories are unfortunately not true. Polar bears are curious and opportunistic animals – if something looks new and potentially edible, they will have a closer look and a nibble. This is true for all polar bears, but especially for those that are summering on land (waiting for the ice to re-form) or those that find themselves in areas with few seals: any food is better than no food, even if it contains very little energy. However, none of these food items are a viable option for keeping polar bears alive long-term; only seal fat has a high enough energy content to do this. A round polar bear is a happy polar bear and it requires a lot of energy to keep a polar bear chubby! The alternative food sources may well add a small portion of energy to the bears’ diet, but in the grand scheme we are talking a fairly insignificant amount. There are two major reasons why the alternative food items cannot work as a full-on substitute for seal: 1) The good alternative food sources are not infinite. Polar bears are sometimes seen foraging in seabird colonies on the steep bird cliffs in the arctic. The bears are quite the avid climbers as you can clearly see in the impressive pictures here http://dailym.ai/1Ndq2L5 and here http://bit.ly/1j7bPm5. The bears also target the ground-nesting geese in the arctic. As an alternative food source, eggs are actually a reasonably energy rich food. However, bird eggs are very small compared to a seal, meaning that the bears must consume a much higher number of eggs to get the same amount of energy they would from eating a single seal. This means that a single bear visit can be absolutely devastating to a bird colony (see this link for an example re. goose eggs: http://bit.ly/1YZnPGw). In other words, eating eggs may well be a good strategy for a while, but if the majority of the eggs produced by the birds in a specific colony are eaten every year, it won’t take long before that colony simply doesn’t exist anymore. In other words, bird eggs are a nutritionally sound alternative to seals, but they simply aren’t abundant enough to ensure the long-term survival of polar bears. The same is true for caribou as well as dolphins and other whales such as belugas – there simply aren’t enough of them around to sustain the world’s population of polar bears (http://bit.ly/1L5aR4M). 2) Polar bears are not made for hunting on land. Polar bears are marine mammals and not specialized for hunting by running on land for an extended period of time, e.g. when chasing geese or caribou (the bears severely overheat very quickly, even in cold temperatures). A persistent bear may well get a caribou every now and then, but most healthy adult caribous paying attention to its surroundings should be able to outrun a bear. This means that catching such terrestrial prey is often very energy demanding. Polar bears are curious creatures and opportunistic feeders, so I am by no means suggesting that they won’t try, but it means that feeding on geese or caribou does not constitute a solution for long-term polar bear survival. If the bear is to stay round and healthy, its overall energy intake must be at least equal to its energy expenditure. Otherwise you will ultimately end up with a very skinny bear that doesn’t have the energy to reproduce, to nurse its cubs, to stay warm during the winter months, to hunt successfully on the ice, etc. etc. In other words: the polar bears are not adapting long-term, they are simply doing their best to survive short-term while waiting for the ice and the seals to come back.  *This image is copyright of its original author Note: Dr. Thea Bechshoft, is a Polar bear expert and researcher 
This is insane. A video that shame us of being human being, such a brutality for an endangered species. In this video some bloody idiots are killing a polar bear without any mercy
 (10-31-2015, 01:57 PM)sanjay Wrote: This is insane. A video that shame us of being human being, such a brutality for an endangered species. In this video some bloody idiots are killing a polar bear without any mercy Poor bear, cursed that guy..Why this kind of man still exists in this world? He shot the bear repeatedly and the bear were screaming in agony, and beg for mercy.. And why the authorities did not do anything about this insane guy? 
Question from Viola:
"Thea, do you know how much milk polar bear cubs consume?" Answer by Dr. Thea Bechshoft: Viola – good question (and one that took me to new nooks and crannies of the polar bear literature). Healthy polar bear cubs increase massively in weight from the day they are born (500-800 gram) to the day they emerge with their mother from the maternity den (10-12 kg). This rapid weight gain comes from the cubs drinking their mother’s milk. Polar bear milk is the most fatty of any bears’. It contains about 40% fat when the cubs first start nursing, and decreases to around 20% as the cubs grow older. The fat percentage and the quality of the milk is of course also dependent on the mother’s body condition – the less body fat she has, the less fat she will be able to pass on to the cubs through her milk. Although quite a few studies have looked into the quality and composition of polar bear milk, only one group of researchers have looked at the amount of milk consumed by polar bear cubs: in their study published in 1990, the researchers Arnould and Ramsay estimated that polar bear cubs in Western Hudson Bay during the ice-free period consumed 469 gram milk/day for cubs of the year (those under 1 year of age) and 131 gram milk/day for yearlings (those over one year old, but still with their mother and still nursing). Another way you could try to get this question answered would be to contact a zoo that has had to hand-raise a polar bear cub. Although the milk formula used for hand rearing the cubs has a somewhat different composition than actual polar bear mother’s milk, it should still give you an indication of how much the cubs consume. I’ve found two videos of nursing polar bears: a polar bear nursing her single 2-3 month old cub (http://bit.ly/1ly7GZR) and a polar bear nursing her nearly 2 year old twin cubs (http://bit.ly/1M5yuW2) Finally, for comparison: human babies drink about 750 ml  approx. 750 gram) milk per day during their first 6 months (there is of course a huge variation - as mentioned, this is on average). However, human breast milk is only about 4% fat, meaning that human babies may drink more milk, but polar bear cubs have a much higher energy intake per serving.
Update: Collared Bear
 *This image is copyright of its original author  *This image is copyright of its original author The Southern Beaufort Sea is unbelievably big—more than the size of seven New Jerseys. Details... © Daniel J. Cox/Natural Exposures.com Monday, November 16, 2015 - 14:06 "Several people have contacted us about a photo of a large polar bear with a collar that is clearly too tight. The image was reportedly taken near Kaktovik, Alaska, at a site where groups of polar bears have been gathering in recent years to feast on the remains of bowhead whale carcasses. This area has become unique in the Arctic for having predictable and substantive remains from whales taken by subsistence hunters—producing some of the largest bears seen anywhere. When we learned of the situation, we reached out to management authorities in northern Alaska to learn more and see what might be done to help. We discovered that federal authorities in both the U.S. and Canada, along with university research partners, had already been notified and were actively working on a response to hopefully locate the bear and remove the collar. While it may sound simple, the logistics, skills, and regulations surrounding wildlife capture in the Arctic are quite challenging. Wildlife capture work in general has inherent risks as it requires low level and very technical flying skills and accurate darting ability. In the U.S., federal agencies have very specific requirements for both aircraft and pilots involved in capture work. Locating a certified helicopter paired with a certified pilot and getting both to the North Slope of Alaska with certified and permitted capture pilots is no quick or easy task. By the time the information was given to the correct authorities and they were able to verify the situation on the ground and begin a response, the sea ice had returned to the area and the bears had largely departed. The collared bear hasn’t been seen since that time and is unlikely to return to shore until the ice melts again next summer. There is a high probability it will return to Kaktovik next summer to feed on whale carcasses again, giving authorities a better chance to remove the collar—unless it has already fallen off on its own (each collar is equipped with a release mechanism, although this one appears to have failed along with its transmitter). What can be done in the meantime? As long as the bear remains on the ice, finding it is next to impossible. The Southern Beaufort Sea is unbelievably big—more than the size of seven New Jerseys—and polar bears often have enormous home ranges. The best hope is that the collar finally falls off on its own or that the bear is sighted and reported to authorities. We wish there were an easy answer to this complex problem. We can report, however, that the fact that the bear hasn’t been found yet isn’t due to a lack of will by all involved. “Fortunately, injuries from collars are very rare around the Arctic and across bear species,” said Geoff York, our senior director of conservation, “but scientists need to do all they can to ensure the safety of the bears. The situation in Kaktovik—where polar bears put on an enormous amount of weight from feasting on whale carcasses—is a fairly new phenomenon. Given what scientists have learned about the rapid weight gain of bears in that area, they will need to make adjustments in procedures and/or collar technology to make sure this never happens again.” PBI is actively talking to research partners to explore ways to help improve collar design, materials, and release mechanisms. While tracking information provides vital insights into polar bear conservation, scientists are also looking at alternative methods to gather information on this species that lives much of its life out of human sight. Rest assured we are aware of this situation and share concerns about the welfare of this bear—and will provide updates as we learn more." There are much less prey items in the Arctic now than there were in the 60s or 1000s. The polar bears consume as much as possible these days (hence the "new phenomenon") to keep energy for a longer period of time as well as to keep hunger away. They never know when they'll get their next prey. Most of these preys remain unequally scattered throughout the Arctic, and thus results in a lesser weight and more aggression/competition over prey among modern polar bears. I just wish the Pleistocene was today, so I could see the most massive polar bears as an average population. Also, I really don't support collars for this species since it restricts their neck's range of motion, the neck being one of it's most important tools for flexibly catching seals and other prey.
Here is a disturbing footage of a female Polar bear getting fed with some firecracker in the meal by some sadistic cook.
Her jaw and throat were blown off.
So many Polar bears taken down by those ivory hunters.
 *This image is copyright of its original author  *This image is copyright of its original author
How beautiful and healthy this world could be without the human-virus. How do you rid the world of a plague when you are the plague? A no-win situation. Years ago, when watching Star Trek, I thought... "why not a full-planet wildlife refuge?" But that is just a pipe-dream.
(01-01-2016, 04:06 AM)brotherbear Wrote: How beautiful and healthy this world could be without the human-virus. How do you rid the world of a plague when you are the plague? A no-win situation. Years ago, when watching Star Trek, I thought... "why not a full-planet wildlife refuge?" But that is just a pipe-dream. True. Looks like we won't be dying until we decide to. |
How can humans be so cruel!?
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