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Post by oldindigosilverback on Mar 30, 2022 6:58:38 GMT -5
Gene study explores polar bears’ weight-gain secret. Study looks at how genes keep polar bears fit despite half its entire bulk being 50 per cent fat A polar bear outside Churchill, Manitoba: experts at NUI Maynooth and Dublin City University analysed the genomes of 70 polar bears to find out what allows them to be so fat yet completely healthy. Photograph: AFP Photo/Paul J Richards When it comes to weight gain, nothing tops the polar bear. Yet the very fact that it remains fit and healthy despite half its entire bulk being pure fat could help us tackle heart disease in humans. Irish researchers were deeply involved in an international study of the bears that focuses on their genes. Experts on genetic evolution at NUI Maynooth and Dublin City University analysed the genomes of 70 polar bears in a hunt for what it is that allows them to be so very fat yet completely healthy. Beijing Genomics Institute, the largest of its kind in the world, led the international project. It provided the bear genomes, derived from tissue samples gathered by scientists from populations around the high Arctic. Science Foundation Ireland supported the labs here. Largest project “Outside of humans, this is the largest mammal genome project ever undertaken,” said Prof James McInerney, an evolutionary biologist and professor in NUI Maynooth’s department of biology. “How is this study relevant to humans? This is the most extreme animal. A mature male will be 50 per cent fat. A human like this would be incredibly obese and unhealthy,” he said.Many other labs were involved in the study, which is published this evening in the journal Cell. “This is a really large international effort,” said Dr Mary O’Connell, a principal investigator in Dublin City University’s school of biotechnology. “I took the genome data and tried to identify differences in the same gene across many species,” she said. “It is very exciting really; you start on these projects and you start digging and you don’t know what you are going to find.” Bear genes When they started to look for differences, out popped genes related to fat metabolism, what the bears do with their cholesterol and their cardiovascular function. Knowing how the bear genes work should provide a better understanding of how human genes differ and why our systems cannot tolerate so much fat. One of the significant finds was how fast the polar bear genes evolved away from their brown bear origins. Earlier studies estimated polar bears could have evolved up to five million years ago. The international study revealed they evolved somewhere between 400,000 and 600,000 years ago representing just 60,000 generations. “This is surprising because they are quite different to brown bears,” said Prof McInerney. “They must have evolved incredibly quickly. The hair colour is easy but not the metabolism and coping with their extreme life on the ice.” The data should also help conserve these animals. There are only about 14 populations around the high Arctic and 10 are in decline, he said. The goal will be to protect the widest possible genetic diversity and avoid inbreeding that could bring an end to these amazing creatures. www.irishtimes.com/news/science/gene-study-explores-polar-bears-weight-gain-secret-1.1788468
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Post by oldindigosilverback on Mar 30, 2022 7:00:12 GMT -5
/\ I agree of what most of the article above says except that mature males have 50% fat. That 50% fat clearly belongs to pregnant females. Pregnant female polar bears can reach 1000 pounds, something the largest female does not reach.
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Post by Gorilla king on Mar 30, 2022 11:44:30 GMT -5
Awesome. For those who say fat is bad for bears.
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Post by oldindigosilverback on Mar 31, 2022 2:58:32 GMT -5
Awesome. For those who say fat is bad for bears. I second that and agree with you but I still believe that male polar bears average 30% fat, a constant autumn period while pregnant females reach 50% fat. Besides, I doubt big cats are 95% muscles. They do have muscles but other parts of their body are made of bones, intestines , and fur. The bear outclasses a big cat in terms of bone density, thickness of fur, and grappling ability.
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Post by Gorilla king on Mar 31, 2022 5:49:07 GMT -5
Awesome. For those who say fat is bad for bears. I second that and agree with you but I still believe that male polar bears average 30% fat, a constant autumn period while pregnant females reach 50% fat. Besides, I doubt big cats are 95% muscles. They do have muscles but other parts of their body are made of bones, intestines , and fur. The bear outclasses a big cat in terms of bone density, thickness of fur, and grappling ability. Yeah, in a sample of 10 male polar bears, their fat % was between 2 and 21%, an 8 year old, 407 kg male had only 17.8%. All the females in the sample were below 2 years old, so irrelevant.
Reply # 13
beargorillarealm.proboards.com/post/621/thread
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Post by oldindigosilverback on May 31, 2022 2:17:28 GMT -5
Polar bears and cetaceans are the least adaptable to climate and temperature change. This is why they are the least suitable for captivity.
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Post by Gorilla king on May 31, 2022 20:59:21 GMT -5
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Post by oldindigosilverback on Jun 1, 2022 21:35:33 GMT -5
/\ That is a fairly large and powerful male. His shoulder hump seems more developed than that of other bears.
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Post by brobear on Jun 2, 2022 2:27:11 GMT -5
/\ That is a fairly large and powerful male. His shoulder hump seems more developed than that of other bears. That's simply the angle of the camera shot. Polar bears have very abbreviated shoulder humps. Truly not worthy of mention.
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Post by oldindigosilverback on Jun 2, 2022 4:14:55 GMT -5
/\ That is a fairly large and powerful male. His shoulder hump seems more developed than that of other bears. That's simply the angle of the camera shot. Polar bears have very abbreviated shoulder humps. Truly not worthy of mention. I agree brown bears have a more impressive shoulder hump. Still some male polar bears display a slight shoulder hump (which is still impressive considering it is rarely seen).
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Post by oldindigosilverback on Jun 7, 2022 7:49:51 GMT -5
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Post by arctozilla on Jul 1, 2022 3:30:43 GMT -5
/\ yes, they probably do. Polar bears are unlike most bears hyper-carnivorous, meaning they have teeth and claws adapted for a predatory diet. Their teeth are also much thicker and longer than brown bears.
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Post by oldindigosilverback on Jul 7, 2022 10:41:38 GMT -5
" ...The marquee attractions of Victorian circuses, felines commanded the lion's share of top-quality food. The menu du jour of Alexander Fairgrieve's famous traveling menagerie offers some sense of the pecking order among the various animals. Elephants had to content themselves with "hay, cabbages, bread and boiled rice, sweetened with sugar" while the big cats feasted on "shins, hearts, and heads of bullocks." So much meat did the lions and tigers of the great circuses consume, in fact, that their fellow carnivores the bears were forced to await the onset of "very cold weather" before they were similarly provisioned. Until such time, they subsisted on bread, sopped biscuits, and boiled rice. To be an ursine understudy to feline stars was a sad fate, indeed. Should you wish to express dietary soliditary with the dancing bears of Victorian circuses, this recipe for boiled rice with cheese, which appears in The Helping Hand Cook Book (1912), will have you looking forward to winter's chill..." theausteritykitchen.com/2011/09/circus-animals-nutrition.htmlToledo Zoo - Polar Bear Skulls The skull on the right is a healthy bear, the skull on the left is of a bear fed a poor diet www.flickr.com/photos/fkalltheway/4487583366/in/photostreamA REVIEW OF LIONS & POLAR BEARS PROLOGUE "There are currently about 1,000 polar bears held captive in zoos around the world. Most of them are held in hard, biologically deficient exhibits that are a key factor in their physical and mental deterioration. A wide range of problems, including aberrant behaviours like repetitive pacing and swimming, poor cardiovascular health and lack of muscle mass, are more or less ubiquitous in captive polar bears. A significant number of captive polar bears are held in temperate and tropical zoos where they experience chronic heat stress, climate induced hair loss and other conditions. The world population of captive polar bears is unhealthy and compromised." www.zoocheck.com/calgaryCorpAffairsemail.htmlshaggygod.proboards.com/thread/798/historical-accounts-bears-big-interactions?page=2Two of the links are no longer active but the accounts are found on the now dead shaggybear forum.
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Post by oldindigosilverback on Jul 10, 2022 0:58:53 GMT -5
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Post by oldindigosilverback on Jul 10, 2022 1:00:18 GMT -5
How do we track the bears? "Scientists observe the bears in their natural habitats and use radio collars to track their movements. The collar sends signals via satellite that are used to plot the bear's path." "Only female polar bears can be tracked using radio collars. Male polar bears have necks that are wider than their head, so the collars simply fall off." arcticwwf.org/species/polar-bear/tracker/
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Post by Montezuma on Jul 10, 2022 1:45:47 GMT -5
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Post by Montezuma on Jul 10, 2022 2:06:42 GMT -5
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Post by Montezuma on Jul 10, 2022 2:11:12 GMT -5
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Post by Montezuma on Jul 10, 2022 2:13:22 GMT -5
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Post by oldindigosilverback on Sept 7, 2022 7:51:38 GMT -5
Polar Bears have Black Skin Under Their White Fur. The Arctic is home to a wide array of winter wildlife and therefore the polar bear is the most iconic symbol of the Arctic. Perhaps no creature sparks as much fascination as the polar bear. This majestic animal is sort of mythical in its perception and has inspiring stories and legends across the world, while also evoking much curiosity. A great white bear asleep on the Arctic may appear as nothing more than a snowbank until a black nose pokes out from underneath a coat of thick fur. And that brings us to a question here. Are polar bears black in colour? In the eyes of the onlooker, the polar bear is roofed in a blanket of white fur. However, the hair in its heavy coat is transparent and they form two layers. The coarse outer layer is made of long tapered hair, while the dense undercoat consists of shorter insulative hair. And this double-layered coat prevents heat from escaping the body of the polar bear. Their coat is so well camouflaged in Arctic environments that it can sometimes pass as a snowdrift. Interestingly, the polar bear’s coat has no white pigment; instead, it is black and their thick layer of body fat helps to soak within the sun’s warming rays which keep them warm even when swimming, and a double-layered coat that insulates them from the cold Arctic air. Fur even grows on the underside of their paws, which protects against cold surfaces and provides a decent good grip on ice. Adaptations Polar bears have a special set of adaptations that allow them to reside in the cold Arctic. The most famous of these adaptations is their stark white coat which provides camouflage in surrounding snow and ice in search of a seal to eat. The hair of the polar bear features a structural colour, which comes from the way light bounces around the structure of the hair itself without any pigment. Unlike human hair, polar bear’s fur being hollow and tube-like, are too small to see without a microscope, but there’s enough room for light to scatter inside. Some scientists were accustomed to thinking that this hollow hair might do more than just help bears blend in. They thought the structure of the hair, along with the black skin beneath, allowed polar bears to soak up far more heat from sunlight than other animals can as one wonders how animals manage to stay so toasty warm in Arctic conditions. However, the experiments showed that very little sunlight makes it down the hairy tubes to touch the bare skin of bears. Conclusion Thus, the Polar bear’s white appearance helps it camouflage in snowy surroundings, but it looks are all deceiving due to a dense, insulating underfur which is further topped by guard hair. And each hair shaft is pigment-free and transparent with a hollow core that scatters and reflects the visible light, much like what happens with ice and snow. science.zeba.academy/polar-bears-have-black-skin/amp/
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