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Post by King Kodiak on Apr 22, 2020 6:06:03 GMT -5
How fat grizzly bears stay diabetes-free Every fall, grizzly bears pack on the pounds in preparation for their winter hibernation. In humans, such extreme weight gain would likely lead to diabetes or other metabolic diseases, but the bears manage to stay healthy year after year. Their ability to remain diabetes-free, researchers have now discovered, can be chalked up to the shutting down of a protein found in fat cells. The discovery could lead to new diabetes drugs that turn off the same pathway in humans. The findings are “provocative and interesting,” says biologist Sandy Martin of the University of Colorado, Denver, who was not involved in the new work. “They found a natural solution to a problem that we haven’t been able to solve.” As people gain weight, fat, liver, and muscle cells typically become less sensitive to the hormone insulin—which normally helps control blood sugar levels—and insulin levels rise. In turn, that increased insulin prevents the breakdown of fat cells, causing a vicious cycle that can lead to full-blown insulin resistance, or diabetes. SIGN UP FOR OUR DAILY NEWSLETTER Get more great content like this delivered right to you! Developing new diabetes drugs has been hampered by the fact that findings from many mouse models of diabetes have not translated to humans. So Kevin Corbit, a senior scientist at Thousand Oaks, California–based drug company Amgen, decided to start looking at obesity and metabolic disease in other animals. “When I was thinking about things that are quite fat, one of the first things I thought of was bears, and what they do to prepare to go into hibernation,” he says. “But of course you don’t see bears running around with diabetes and heart disease.” Corbit and scientists at the Washington State University Bear Center in Pullman measured blood sugar levels, insulin levels, body weight, and other markers of the metabolism in six captive grizzly bears before, during, and after hibernation—in October, January, and May. Surprisingly, even as each bear gained more than a hundred pounds in the fall, their cells remained sensitive to insulin, and their insulin and blood sugar levels stayed constant. In people, such an immense weight gain would likely cause insulin resistance. It wasn’t until well after they’d begun hibernating that bears experienced a temporary, seasonal episode of insulin resistance, but even that was completely reversed come springtime. “This type of physiology had never been described before and was completely opposite what’s seen in humans,” Corbit says. When he and his collaborators analyzed levels of more molecules in the bears’ blood, liver, and fat cells, they found out what was controlling the insulin sensitivity and resistance independently from weight gain or loss: a protein called PTEN. In the fall, the bears have switched-off versions of PTEN present in their fat cells, Corbit’s team reports today in Cell Metabolism. As a result, the cells continue responding to insulin—and the signals to store sugar—even as the bears gain weight. For bears, the shutdown protein helps maximize sugar storage in their bodies for the long winter ahead. The finding could also help humans, Corbit says. Because shutting off PTEN helps obese bears maintain insulin sensitivity, turning off the pathway in overweight people could prevent or treat diabetes, he suggests. Interestingly, he points out, a previous study found that people missing one gene for PTEN production are less likely to develop metabolic or cardiovascular disease even as they gain weight. Those people do develop other diseases, including cancer, but Corbit suspects that’s because the PTEN levels are diminished body-wide. If scientists could turn it off only in fat cells—like bears do—these side effects might be diminished. Metabolic disease specialist Abhimanyu Garg of the University of Texas Southwestern Medical Center in Dallas says that more evidence is needed to support any link between the bear finding and human diabetes. And you’d have to be careful with a drug that turns off PTEN, even if it’s only in fat cells, he says. Even if it could treat diabetes, it might also cause increased weight gain. After all, it helps bears store up their winter fat, Garg notes. “You might create a situation where patients are metabolically healthy but you’re trading that for joint problems and back problems and arthritis.” www.sciencemag.org/news/2014/08/how-fat-grizzly-bears-stay-diabetes-free#
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Post by brobear on Jul 2, 2020 8:13:24 GMT -5
This topic comes up waay too often. So, here we will gather the data of just how fat a bear really is. Pictured: This NPS photo of 747 epitomizes an obese bear. (He should’ve won #FatBearWeek. Election was rigged!) Seriously, this is an extremely obese bear. I don’t think I’ve ever seen a bear this fat before. His belly hangs nearly to the ground (the water is not very deep where he stands in the photo). 747 is a very dominant adult male at Brooks Falls. As such, he has access to his choice of fishing spots. His well-endowed figure is proof of his dominance, health, and fishing skills.
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Post by brobear on Jul 2, 2020 8:15:16 GMT -5
fitznaturalist.com/2016/10/27/brown-bear-fatness-index/ BROWN BEAR FATNESS INDEX - OCTOBER 27, 2016 / MIKE FITZ Brown bears get fat, often really fat. They also lose a lot of weight and sometimes become really skinny. They are often fat and skinny in the same year. When you watch brown bears, either in person or via bearcam, you can sometimes make a fairly accurate determination of a bear’s body fat and relative health by looking at its shape. Fatness can be used as an indicator of health in brown bears. Brown bears need to eat a year’s worth of food in six months or less to survive, and body fat is the key their survival. They can lose 30% or more of their body weight during hibernation and can continue to lose weight throughout the spring when few high calorie foods are available. In the Brooks River area, only after green plants begin to grow and salmon have arrived do most bears begin to regain lost weight and start to accumulate body fat. While fat is important to bears, a thin bear isn’t necessarily an unhealthy bear. Young subadult bears and yearling cubs, for example, often appear thin in spring and early summer before many high calorie food sources are available. These bears usually regain lost body mass in summer and early fall. Polar Bear International developed a handy scorecard to measure the relative fatness of polar bears. I’ve adapted it for brown bears. My brown bear fat index uses the same categories as the polar bear index, which ranges from skinny/emaciated to very fat/obese. I also included additional information for each category such as the age/sex class most likely to be in a category and the time of year bears are most likely to be in a category. Please note, my brown bear index is subjective and based on my observations at Brooks River, Katmai National Park, Alaska. The polar bear fatness index is also subjective, but less so than mine because researchers who handle immobilized bears can palpate the animal to estimate its body fat content. (Katmai’s Changing Tides project also tracks body fat content in female brown bears, but uses bioelectric impedence analysis.)
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Post by OldGreenGrolar on Jul 2, 2020 8:16:24 GMT -5
Fat is not useless. Bears are made to sustain heavy weight with their bones.
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Post by King Kodiak on Jul 2, 2020 8:31:58 GMT -5
Actually bears dont get fat at all, at least not in the way people think. So much so that scientists study them to try to cure obesity.
Could bears hold the cure to OBESITY? Grizzlies eat up to 58,000 calories a day yet don't get fat or develop heart disease
Before hibernation, grizzlies eat around 100lbs worth of nuts, salmon and berries which increases cholesterol and causes blood pressure to jump
Yet unlike humans they do not suffer heart attacks or clogged arteries - and crucially, they don't become diabetic
U.S. drug maker Amgen is now researching 12 grizzlies held in captivity at Washington State University to work out how they manage to stay healthy
Scientists are studying grizzly bears in the hope they can help solve the worldwide obesity crisis - because they are surprisingly good slimmers.
A study has begun into the fearsome 1,000lbs creatures because they eat up to 58,000 calories a day but don't get fat.
Before they hibernate grizzlies eat around 100lbs worth of nuts, salmon and berries which increases their cholesterol and causes their blood pressure to jump.
Yet unlike humans, they do not suffer heart attacks or clogged arteries - and they don't become diabetics.
U.S. drug maker Amgen is now researching 12 grizzlies held in captivity at Washington State University to work out how they do it.
Dr Kevin Corbit has been looking at their fat deposits, monitoring their hearts, analysing their blood and conducting biopsies in the hope the bears will yield their weight loss secrets.
It is the only facility in the world housing adult grizzlies and offers a unique opportunity to study them.
According to the Wall Street Journal, Dr Corbit was inspired by Yogi Bear and his portly figure when trying to think of a way to research weight loss.
Dr Corbit plans to spend the next two years working out how exactly the mechanism works. His work will be assisted by the sequencing of of the bears' genome which he hopes will be completed soon.
The Washington State University bear centre was set up 27 years ago and the animals there were born on site or rescued from places where they went too close to humans such as in a national park.
Dr Corbit, who until now has only worked with rats in a laboratory, had to take extra precautions when dealing with the grizzlies.
The facility where they are held has electric fences buried underground so the bears can't dig them up.
The bears themselves are kept in steel crates when they are being inspected and are put under before samples are taken.
Dr Corbit has also become adept at using honey to distract them whilst another resarcher scans their hearts.
Amgen research executive Dr Alexander Kamb said the grizzly bear research was unusual but given how big an issue obesity had become, it made sense to think differently.
He said: 'I want to learn how the grizzly bears work their magic'.
www.google.com/amp/s/www.dailymail.co.uk/sciencetech/article-2524726/amp/Could-bears-hold-cure-OBESITY-Grizzlies-eat-58-000-calories-day-dont-fat-develop-heart-disease.html
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Post by King Kodiak on Jul 2, 2020 8:48:20 GMT -5
If the above article is not proof enough to debunk someone about bears being fat, then i dont know what is. Scientists study grizzlies to cure obesity for god's sake. Fat does not make bears obese or unhealthy.
For bears, the more fat and weight, the better. More stronger and healthier. For big cats, its the other way around, the more fat the worse.
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Post by brobear on Jul 2, 2020 9:33:41 GMT -5
If the above article is not proof enough to debunk someone about bears being fat, then i dont know what is. Scientists study grizzlies to cure obesity for god's sake. Fat does not make bears obese or unhealthy.
For bears, the more fat and weight, the better. More stronger and healthier. For big cats, its the other way around, the more fat the worse. Actually, we have some information lost within our massive collection of unorganized data. By Peter ( maybe ).
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Post by King Kodiak on Aug 7, 2020 9:54:20 GMT -5
Estimated survival time for bears having different denning body fat contents and experiencing different reproductive strategies. The lines represent the number of days before 30% of lean mass loss is reached (survival threshold). Initial body lean mass was 100 kg. Bars are three times SD. Horizontal gray lines represent a different length of hibernation (120, 150, 180 and 210 days).
... Fat accumulation based on energy acquired in autumn is crucial for the survival of bears. In fact, modeling to assess energetic costs suggests that it is possible that brown bears may die during hibernation if they are unable to accumulate sufficient fat during autumn (L opez- Alfaro et al. 2013). In the current study, the energy balance became substantially positive from September to November because digestible energy intake rose during that period, while energy expenditure remained the same. ... .. Brown bears do not consume food during the long denning season, but rather rely solely on body reserves (Hilderbrand et al. 2000). After this period of dormancy, replenishing nutrient stores is a priority for bears (L opez-Alfaro et al. 2013). Likely due to their short active period and limited food resources, brown bears in the Arctic are significantly smaller and exit the den with less than half the absolute fat stores of bears from other Alaskan populations (Hilderbrand et al. 2018b). ... www.researchgate.net/figure/Estimated-survival-time-for-bears-having-different-denning-body-fat-contents-and_fig5_260057822
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Post by King Kodiak on Oct 3, 2020 8:27:58 GMT -5
How scientists try to weigh some of the fattest bears on Earth
The Alaskan ursines of “Fat Bear Week” are very heavy indeed. Laser scanning can help measure their size.
The team processed the information by digitally removing rocks and plants from the images, and found the volume of the bear’s bodies.J. Cusick / NPS.
www.popsci.com/story/technology/fat-bear-week-laser-scanning-weight-estimates/
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Post by brobear on Oct 6, 2020 13:48:42 GMT -5
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Post by brobear on Oct 7, 2020 4:40:02 GMT -5
www.seeker.com/why-polar-bears-are-fat-but-have-healthy-hearts-1768544058.html Why Polar Bears Are Fat, But Have Healthy Hearts Polar bears appear to be genetically superior to humans when it comes to warding off heart disease, a new study on the hefty bears finds. What's remarkable is that polar bears are among the most fat-obsessed beasts in the animal kingdom. "The life of a polar bear revolves around fat," according to Eline Lorenzen of UC Berkeley who worked on the study. It's published in the latest issue of the journal Cell. "Nursing cubs rely on milk that can be up to 30 percent fat and adults eat primarily blubber of marine mammal prey," Lorenzen explained. "Polar bears have large fat deposits under their skin and, because they essentially live in a polar desert and don't have access to fresh water for most of the year, rely on metabolic water, which is a byproduct of the breakdown of fat." Our culture is fat-phobic, valuing skinny people who ideally eat low-fat diets, so how is it that evolution has led to fat polar bears that eat mostly fat? Lorenzen and her colleagues looked at the genomes of 79 polar bears from Greenland and 10 brown bears from different locations around the globe to answer that question and more. They first determined that polar bears and brown bears diverged less than 500,000 years ago. That's incredible, considering that prior theories estimated the two species parted evolutionary ways up to 5 million years ago. "In this limited amount of time, polar bears became uniquely adapted to the extremities of life out on the Arctic sea ice, enabling them to inhabit some of the world's harshest climates and most inhospitable conditions," the study's senior author Rasmus Nielsen, also of UC Berkeley, said in a press release. Up to half of the body weight of polar bears consists of fat, and their blood cholesterol levels are high enough to cause cardiovascular disease in humans. Nielsen and his team, however, discovered that mutations in genes involved in cardiovascular function allowed polar bears to rapidly evolve the ability to consume a fatty diet without developing high rates of heart disease. One such gene, called APOB, is known to play a role in moving cholesterol from the bloodstream into cells, thus reducing the risk of heart disease. "Such a drastic genetic response to chronically elevated levels of fat and cholesterol in the diet has not previously been reported," co-author Eske Willerslev of the University of Copenhagen said. "It certainly encourages a move beyond the standard model organisms in our search for the underlying genetic causes of human cardiovascular diseases." Polar bears might therefore hold the genetic key to humans avoiding heart disease. Hopefully these majestic animals will still be around for us to benefit - and admire. Heart attacks aren't doing them in, but declining habitat due to disappearing Arctic sea ice is. It's estimated that the worldwide population of polar bears is only about 20,000 to 25,000.
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Post by brobear on Oct 7, 2020 8:25:36 GMT -5
*What I'm searching for: I have read information ( data ) on brown bear fat which states that from early Spring and into early Summer, brown bears are not fat. No more so than other predators such as Canids or Felids.
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Post by brobear on Nov 6, 2020 3:15:13 GMT -5
* What I'm searching for: I have read information ( data ) on brown bear fat which states that from early Spring and into early Summer, brown bears are not fat. No more so than other predators such as Canids or Felids. How does the body fat ratio of a brown bear from early Spring into mid-Summer compare with that of canids and felids?
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Post by OldGreenGrolar on Nov 6, 2020 9:42:04 GMT -5
* What I'm searching for: I have read information ( data ) on brown bear fat which states that from early Spring and into early Summer, brown bears are not fat. No more so than other predators such as Canids or Felids. How does the body fat ratio of a brown bear from early Spring into mid-Summer compare with that of canids and felids? Not too sure. However, I believe during the cold, their fur grows thicker. Regardless, bear bones are made to sustain the weight they carry.
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Post by OldGreenGrolar on Nov 12, 2020 11:01:39 GMT -5
A fat heavy Asian defeats the muscular but lighter Australian Nathan Jones. That is how a fat bear will win.
I believe one can be fat and still utilize their weight well.
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Post by OldGreenGrolar on Nov 14, 2020 1:52:39 GMT -5
I have seen some videos of sumo wrestler losing in fights to lighter and more athletic men. However, unlike bears most humans are not able to sustain such heavy weights.
Bears possess much greater bone density than humans and other extant predators.
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Post by brobear on Nov 14, 2020 4:09:06 GMT -5
Some great information posted here. Appreciated. What I would seriously like to discover is the actual fat percentage ( average / typical ) of a bear and how that compares with other Carnivorans outside of the Autumn months.
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Post by King Kodiak on Nov 14, 2020 9:04:56 GMT -5
Body and Diet Composition of Sympatric Black and Grizzly Bears in the Greater Yellowstone Ecosystem
Abstract
The Greater Yellowstone Ecosystem (GYE) has experienced changes in the distribution and availability of grizzly bear (Ursus arctos) food resources in recent decades. The decline of ungulates, fish, and whitebark pine seeds (Pinus albicaulis) has prompted questions regarding their ability to adapt. We examined body composition and diet of grizzly bears using bioelectrical impedance and stable isotopes to determine if 1) we can detect a change in diet quality associated with the decline in either ungulates or whitebark pine, and 2) the combined decline in ungulates, fish, and pine seeds resulted in a change in grizzly bear carrying capacity in the GYE. We contrasted body fat and mass in grizzly bears with a potential competitor, the American black bear (Ursus americanus), to address these questions. Grizzly bears assimilated more meat into their diet and were in better body condition than black bears throughout the study period, indicating the decline in ungulate resources did not affect grizzly bears more than black bears. We also found no difference in autumn fat levels in grizzly bears in years of good or poor pine seed production, and stable isotope analyses revealed this was primarily a function of switching to meat resources during poor seed-producing years. This dietary plasticity was consistent over the course of our study. We did not detect an overall downward trend in either body mass or the fraction of meat assimilated into the diet by grizzly bears over the past decade, but we did detect a downward trend in percent body fat in adult female grizzly bears after 2006. Whether this decline is an artifact of small sample size or due to the population reaching the ecological carrying capacity of the Yellowstone ecosystem warrants further investigation. © 2013 The Wildlife Society
Full study:
www.researchgate.net/publication/259539758_Body_and_Diet_Composition_of_Sympatric_Black_and_Grizzly_Bears_in_the_Greater_Yellowstone_Ecosystem
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Post by brobear on Nov 14, 2020 9:48:00 GMT -5
Reply #14 - Some good information; great find.
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Post by theundertaker45 on Nov 14, 2020 10:04:25 GMT -5
The body fat percentage of black bears/grizzlies in summer is ~15-20%; in fall it's between 25-30%. Show that to the big cat fans who always reference a max. number of 40% as the general norm. Also, from the charts I've seen wild lions average ~13% in terms of body fat and larger male big cats almost always come in at ~20%.
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