It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
"Bears are not companions of men, but children of God, and His charity is broad enough for both... We seek to establish a narrow line between ourselves and the feathery zeros we dare to call angels, but ask a partition barrier of infinite width to show the rest of creation its proper place. Yet bears are made of the same dust as we, and breathe the same winds and drink of the same waters. A bears days are warmed by the same sun, his dwellings are overdomed by the same blue sky, and his life turns and ebbs with heart-pulsings like ours and was poured from the same fountain....." John Muir
Last week's local section of The Washington Post celebrated -- yes, celebrated -- the killing of a black bear by an 8-year-old girl. The compassionate among us mourned not just the cruel and completely unnecessary killing of one of nature's most fabulous creatures, but the love of violence and destruction instilled in this child by her family. That certain Americans sadly find valor in killing is beyond doubt. But in many ways, it's also beyond belief. That they would take pleasure in a wantonly destructive act and train this into an 8-year-old female heart is beyond forgiveness. We've heard it all before. Hunters love nature. Hunters work to preserve wildlife. Hunters are great stewards of the environment. Hunters eat what they kill. What was the justification here? That enough bears exist in Maryland to kill them off without destroying the species, as mankind once almost did. Only cowards could find solace, justification and pride in that. There's no sport in taking down a large, lumbering animal with a .243 caliber rifle, the kind used by the young girl portrayed in worshipful prose by the Post. That's the same caliber weapon NATO uses in its assault weapons. There's more technology than sport in today's high-powered, scoped weapons. (The Post did not report whether the rifle she used was scoped or not.)
Polar bears sometimes bludgeon walruses to death with stones or ice
It’s long been said that a piece of ice is the perfect murder weapon In this illustration, which appears in an 1865 book by adventurer Charles Francis Hall, a polar bear uses a rock as a tool to kill a walrus. Some have thought that Inuit reports of this behavior were just stories, but new research suggests not. CHARLES FRANCIS HALL, LIBRARY OF CONGRESS
Walruses, weighing as much as 1,300 kilograms with huge tusks and nearly impenetrable skulls, are almost impossible for a hungry polar bear to kill. But new research suggests that some polar bears have invented a work-around — bashing walruses on the head with a block of stone or ice.
For more than 200 years, Inuit in Greenland and the eastern Canadian Arctic have told stories of polar bears (Ursus maritimus) using such tools to aid in killing walruses. Yet explorers, naturalists and writers often dismissed such accounts, relegating them to myth along with tales about shape-shifting bears.
The persistence of these reports, including one report from an Inuk hunter in the late 1990s, coupled with photos of a male polar bear named GoGo at a Japanese zoo using tools to obtain suspended meat compelled Ian Stirling and colleagues to investigate further.
“It’s been my general observation that if an experienced Inuit hunter tells you that he’s seen something, it’s worth listening to and very likely to be correct,” says Stirling, one of the world’s leading polar bear biologists
The researchers reviewed historical, secondhand observations of tool use in polar bears reported by Inuit hunters to explorers and naturalists as well as recent observations by Inuit hunters and non-Inuit researchers and documented observations of GoGo and brown bears — polar bears’ closest relatives — using tools in captivity to access food. This review suggests that tool use in wild polar bears, though infrequent, does occur in the case of hunting walruses because of their large size, the researchers report in the June Arctic.
“Really, the only species you would want to bonk on the head with a piece of ice would be a walrus,” says Andrew Derocher, director of the Polar Bear Science Lab at the University of Alberta in Edmonton, Canada, who wasn’t involved with the new study. He suspects that it might just be a few polar bears that do this behavior. For example, if a mother bear figured out how to use ice or stone in this way, “it’s something her offspring would pick up on,” but not necessarily a skill polar bears across the Arctic would acquire, he says.
Among animals, using tools to solve problems has long been regarded as a marker of a higher level of what humans consider intelligence. Notoriously smart chimpanzees, for example, craft spears to hunt smaller mammals (SN: 2/28/07). Dolphins carry marine sponges in their mouths to stir sand and uncover prey (SN: 6/8/05). And elephants have been known to drop logs or large rocks onto electric fences to cut off the power supply.
Studies on the cognitive abilities of polar bears are lacking. “We don’t know anything experimental or objective at all,” Stirling says. “However, we have a great deal of observational information that tends to suggest polar bears are really smart.”
Members of the bear family, Ursidae, are typically assumed to have strong cognitive skills as a result oftheir large brains and evidenced by their sophisticated hunting strategies. Studies on captive American black bears have even revealed some mental capabilities that appear to exceed those of primates.
This sculpture in the Itsanitaq Museum in Churchill, Canada shows a polar bear lifting a block of ice above the head of a sleeping walrus.
GLORIA DICKIE
Gabriel Nirlungayuk, an Inuk hunter of Rankin Inlet in Nunavut, Canada, says he has heard such stories of polar bears using tools to hunt walruses. “I’ve seen polar bears since I was probably 7 years old. I’ve been around them, I’ve hunted alongside them, and I have seen their behaviors. The smartest hunters are usually the female bears.” Sometimes, he says, polar bears will trick young seals to come closer by pretending to be asleep in open water. Other times he’s observed that a polar bear can sniff out a seal’s breathing hole in ice, even if it’s obscured by snow.
“I have worked with the Inuit on traditional knowledge for a very long time and one of my favorite subjects is polar bears, because science often suggests one thing and the Inuit say another thing,” he notes.
There are around 26,000 wild polar bears living in 19 subpopulations across the Arctic and sub-Arctic. The bears primarily eat seals, hunting the marine mammals by staking out above their breathing holes. Because of climate change, Arctic sea ice is fast disappearing, and scientists predict that many polar bear populations will be extinct by the century’s end. Desperate polar bears may increasingly attack walruses, but “there are limitations to how many walruses an adult bear can take down,” says coauthor Kristin Laidre, an Arctic ecologist at the University of Washington in Seattle. It takes a lot of energy.
Following publication of the new study, Stirling received a video from U.S. Geological Survey scientist Anthony Pagano, based in Anchorage, Alaska, who had previously attached a GoPro camera to a wild polar bear for a separate project. That footage, Stirling says, shows a female polar bear sliding a large block of ice around before throwing it into the water at a seal.
Monday, June 19, 2023
HEY MISTER LEAVE THOSE BEARS ALONE
Why grizzly bears will start to be trapped in parts of Yellowstone
Hillary Andrews Sun, June 18, 2023
BOZEMAN, Mont. – Scientists will start capturing grizzly bears Monday to study in the greater Yellowstone National Park area. The baiting and trapping operations will continue through August 31 in parts of the Custer Gallatin National Forest as well as private lands.
"Research and monitoring of the grizzly bear population is vital to ongoing recovery and management of grizzly bears in the Greater Yellowstone Ecosystem," said the U.S. Forest Service in a statement.
Grizzlies, once found throughout western North America, were reduced to surviving in only 2% of their historic range by the 1960s, according to the U.S. Geological Survey. In 1973, the Department of the Interior formed the Interagency Grizzly Bear Study Team and Committee.
The green represents the historic range of the Grizzlies and the yellow represents the species current range.
Its findings prompted the lower 48 to list the animal as threatened under the Endangered Species Act due to population and range reduction due to human impact in 1975.
"In the greater Yellowstone ecosystem. Grizzly bear numbers had declined to perhaps fewer than 250," stated the USGS in a preservation video.
After almost 50 years of research, the bears are making a comeback. The USGS said it could be the largest collection of scientific evidence on any bear species in the world
A female grizzly bear exits Pelican Creek October 8, 2012 in the Yellowstone National Park in Wyoming. "Today, the study team estimates that the population has rebounded to a minimum of 700," the USGS continued. "And these bears are now delisted from the Endangered Species Act, though much of the credit goes to the grizzly bear and its resilience over decades of management and landscape changes. Rigorous science that informs effective management decisions is also part of the equation."
Biologists will bait foot snares and culvert traps with natural food like road-kill elk and deer, the Forest Service said. Culvert traps are cages or enclosures with one open end that closes when the bait is pulled.
The committee recommends radio-collaring at least 25 adult females annually. They also collar male bears.
YELLOWSTONE NATIONAL PARK, WYOMING, UNITED STATES - 2017/06/02: A Mother Grizzly and her cub walk through a meadow in Yellowstone National Park. (Photo by Will Powers/SOPA Images/LightRocket via Getty Images)
"Data collected from radio-marked bears provide information necessary for tracking key population parameters," stated the USGS on its site. "By observing radio-collared bears, we document age of first reproduction, average litter size, cub and yearling survival, how often a female produces a litter, and causes of mortality. These data allow us to estimate survival among different sex and age classes of bears."
Grizzlies can weigh up to 600 pounds and eat over 200 food items, including plants, animals and fungi. A bear can live up to 30 years, but they reproduce slowly, said the USGS.
"Since the mid-1980s, science has shown that Yellowstone grizzly bears have increased in number and expanded their range, ensuring the future viability of grizzly bears in the greater Yellowstone ecosystem will require continued public engagement, along with the reliable scientific information that assists wildlife managers in conserving the Yellowstone grizzly bear," explained the USGS.
Officials placed bright yellow signs in baited areas.
The study team conducts similar capture operations in other national parks.
Tracy Arm, a majestic fjord located southeast of Juneau, is being skipped by major cruise lines this season following a massive landslide last summer.
For years, sailing through Tracy Arm in southeast Alaska has been a highlight of many cruise itineraries, drawing visitors with its dramatic fjord landscapes and active glaciers that calve into icy waters.
The narrow passage, framed by rugged wilderness, has long been considered one of the region’s most scenic cruising experiences. However, this season several major cruise lines are choosing to bypass the route.
The decision follows a massive landslide last summer, when a large section of a glacier collapsed into the fjord, triggering a tsunami that sent waves surging high up the opposing mountainside. The event raised concerns about the stability of surrounding slopes, which remain potentially hazardous.
Citing passenger safety and ongoing geological risks, cruise operators have opted to alter itineraries, reflecting a more cautious approach as conditions in the area continue to be assessed.
“Tracy Arm is the majestic princess, you know, she is the queen of fjords,” said travel agent Nate Vallier.
The destination cruise and tour companies have chosen as an alternative – nearby Endicott Arm and Dawes Glacier – is “still beautiful by any means, but it’s just not the same”, he said.
Tracy Arm, southeast of Juneau, is a roughly 50-kilometre fjord that leads to the Sawyer Glacier and features wildlife, including seals and bears.
On 10 August 2025, a landslide originating high on a slope above the toe of the South Sawyer, near the head of the fjord, sent water surging more than a quarter mile (more than half a kilometre) up the mountain wall opposite the slide and out Tracy Arm.
No ships were in the fjord, officials said, and no deaths or injuries were reported. But kayakers camped on an island near where Tracy and Endicott arms meet had much of their gear swept away by the rushing water.
Southeast Alaska, largely encompassed by a temperate rainforest, is no stranger to landslides. And while it's long been known the fjord network in the Tracy Arm region has been susceptible, the slope that failed had not been identified as an active hazard before last summer's collapse, said Gabriel Wolken, manager of the state’s climate and ice hazards programme.
Scientists are working to understand not only what caused the slope to collapse but to understand what other hazards might exist in the fjord, he said.
The area remains unstable, said Steven Sobieszczyk, a US Geological Survey spokesperson. Steep landslide areas continue to change for years after an initial slide, he said by email.
“Continued rockfall and small-scale sliding from the exposed landslide scar are expected and could impact the water, potentially causing a future localised tsunami,” he said.
A cruise ships sails into Tracy Arm fjord in Alaska JOE KAFKA/AP
Major cruise companies, including Holland America, Carnival Cruise Line and Royal Caribbean said in response to inquiries from AP that they are replacing a Tracy Arm visit with Endicott Arm. MSC Cruises, Virgin Voyages and regional tour company Allen Marine also are doing Endicott and Dawes Glacier instead. Norwegian Cruise Line said it does not have voyages sailing by Tracy Arm.
Endicott already has been a stop for some ships previously and an alternative when conditions in Tracy Arm, such as excess ice, have been unsafe.
Vallier, who owns the Alaska Travel Desk, said he would have liked cruise companies to give travellers more advance notice about itinerary changes.
After leaving Seattle, the first ships of the season are due 21 April in Ketchikan and in Juneau the following week.
Seeing a glacier – particularly a dynamic, calving glacier – is a bucket-list item for many tourists, and that's what has made Tracy Arm so popular, he said. While the Mendenhall Glacier in Juneau is a major attraction for the capital city and cruise port, many visitors view it from across a large lake, and it has diminished or entirely retreated from view from some hiking overlooks.
Kimberly Lebeda of Wichita, Kansas, was excited when she booked tickets for a Tracy Arm excursion for her family last year. Lebeda, who researches areas she visits, said she was sold on the scenery.
But the night before the stop, they were told that due to ice in Tracy Arm, they would go up Endicott instead. Her family and others who'd booked the excursion got off the ship and onto a smaller boat with glass windows, abundant seating and snacks. They saw seals on ice floes, waterfalls and “a wall of ice” calve from Dawes Glacier, she said.
She called it “an amazing thing to witness”.
“Was it worth it? Yes, because I don’t know if I'll ever get to do that trip again,” she said. “Again, I haven’t ever been to Tracy Arm so I can’t really compare. But to me, was it worth it and was it exciting? Absolutely.”
Bear with me here as I pun around some great news for Ursus Major. A sancturary for bears and the ancient forest has been declared in B.C.; Great Bear Rainforest.
A dangerous rise in confrontations between wild bears and humans is causing widespread concern across Japan, compelling the government to call on its military for assistance. Authorities are now working alongside residents, who are employing cutting edge tools like drone surveillance and alert systems to monitor the movement of these large animals.
Aljazeera reports that the severity of the situation is clear from the casualty figures. Since April 2025, the nation has seen the highest death toll from bear attacks since record keeping began in 2006. According to an October statement from the Ministry of Environment, at least 13 individuals have lost their lives and over 100 more have been hurt.
This surge in bear attacks, which has necessitated military deployment in some areas, underscores a critical ecological and social problem in Japan: the growing conflict between expanding wildlife populations and human settlements, worsened by environmental factors and rural decline.
Japan is home to two primary bear species. The colossal Brown Bear, weighing over 450kg, is predominantly found on the northern island of Hokkaido. The smaller, more numerous Asiatic Black Bear (or Moon Bear), weighing between 80kg and 200kg, inhabits the more densely populated mainland. Both species are involved in the incidents. Encounters with Asiatic Black Bears are more frequent, but Brown Bear attacks are more dangerous. Shota Mochizuki, an associate professor at Fukushima University, told Aljazeera that Black Bears are widely distributed across Honshu and Shikoku, where many people live. He added that attacks by Brown Bears are far more severe because they are significantly stronger and larger animals.
Worst-hit regions and personal accounts
The crisis has been felt most acutely in Japan’s northern prefectures. Japan’s public broadcaster, NHK, reported that the death toll for the year includes four individuals in Akita, five in Iwate, two in Hokkaido, and one each in Nagano and Miyagi.
Bear sightings in Akita prefecture have risen sixfold this year, and bears have attacked over 50 people since May, mostly by Asiatic Black Bears encroaching upon residential districts. For instance, NHK reports that on November 9, a Black Bear assaulted a 78 year old woman in Gojome Town and subsequently attacked a 50 year old woman who came to her aid, though both survived. An elderly woman was killed after encountering a bear while working on a farm in Akita City in late October. The situation is overwhelming, with Kenta Suzuki, the governor of the mountainous region, saying in an Instagram post that the crisis has exceeded the capacity of local authorities.
The dangers have been evidenced by harrowing personal stories. Billy Halloran, a New Zealander, described being severely mauled by an adult Black Bear, estimated to be around 60 or 70kg, while jogging in the woods of Myoko in northern Japan in early October. In an interview, he told CNN that the bear seized his arm and pushed him to the ground, resulting in a broken arm and injured leg that required three surgical procedures and the insertion of metal plates. Attacks are not limited to remote areas; according to NHK, a bear entered a supermarket in Numata city in central Japan in October and injured shoppers.
The severity of the situation has prompted other nations to issue warnings. The US Department of State issued a "wildlife alert" to its citizens, noting the increased sightings near populated zones, and the UK’s Foreign Office warned in late October British travellers against venturing alone into woodland areas.
Experts point to multiple factors driving the escalation. A primary cause is a significant food deficit in the bears’ natural mountain habitats. Mochizuki told Aljazeera that the bears mainly feed on acorns and beech nuts, which have been scarce this year. He said that when natural sustenance is low, bears are more likely to venture into human settlements. According to the Ministry of Environment, a similar spike in attacks occurred in 2023 following poor acorn yields. Some experts say climate change is a reason for the low production.
Furthermore, bear populations are growing. Mochizuki noted that long-term conservation and reduced hunting pressure have contributed to this increase, resulting in more opportunities for bears to encounter humans. Government figures suggest the overall bear population exceeds 54,000. Mochizuki also highlights that rural depopulation is playing a role. He added that as young people move to cities, unmanaged fields and village edges create easy access routes for the animals.
Government response
The Japanese authorities are responding forcefully. Last week, both the country’s military (Japan Self Defence Forces) and riot police were deployed to Akita. Riot police can shoot bears, but the military is legally restricted to national defence and disaster relief. Mochizuki said the military is supporting licensed private hunters by setting traps and removing shot bear carcasses. He explained that hunters hold official licences and firearm permits to conduct nuisance control, including shooting bears when authorised by prefectural governments.
Local residents are using AI-based surveillance and drone technology to detect bears, according to Akita’s mayor. NHK reported that people are also advised to secure food waste and cut down nut-bearing trees near their homes.
Mochizuki said three key long term preventative measures can prove effective: eliminating food sources around human settlements, installing physical barriers like electric fencing, and enhancing early detection through technology and mobile alerts. He stressed the importance of addressing the shortage of hunters and wildlife staff due to the ageing population, calling for increased recruitment and better education for both residents and tourists.
Sunday, March 13, 2022
Are Polar Bears Altruistic or Just Bad At Math?
Polar bear mothers are known to adopt and raise cubs from non-related litters. Why do they make a multi-year commitment to do it? Getty
In the 21st century, most mentions of polar bears conjure images of stranded bears, on exposed beaches or drifting ice sheets as glaciers melt away into the ocean. The harsh conditions of the rapidly-changing Arctic don’t make it easy for animals to raise the next generation of youngsters, and raising a polar bear cub is a lot of work.
However, polar bears do not meet any of these prerequisites for the evolution of alloparenting. They are solitary, live at low densities far from other groups, and raise cubs that impose a large energetic cost due to their prolonged care. So, why do they do it?
One possible explanation is that new moms gain valuable parenting experience through adoption, increasing the probability of success for a subsequent litter. But this doesn’t seem to be supported by research. The most likely explanation is that polar bears haven’t developed the cognitive ability to keep track of the number or identity of their own cubs. Solitary polar bears don’t cross paths very often, so it’s usually safe for a mother to assume that any cubs within an arm’s reach are hers… with the caveat that she won’t notice if one of her cubs has just wandered into the group and doesn’t belong. It’s also possible that mothers who have lost their own cubs recently are biologically predisposed to parenting, and will adopt any cubs that come her way as her own.
Either way, it looks like this curious case of cub adoption is just another example of an energetically costly mistake, rather than a heartwarming instance of altruism and concern. In the wild, it’s still every parent for themselves in the struggle to survive, and pass their genes to the next generation.
The Estimation of Survival and Litter Size of Polar Bear Cubs By: Douglas P. Demaster and Ian Stirling Bears: Their Biology and Management, Vol. 5, A Selection of Papers from the Fifth International Conference on Bear Research and Management, Madison, Wisconsin, USA, February 1980 (1983), pp. 260-263 International Association for Bear Research and Management
The Status and Conservation of Bears (Ursidae) of the World: 1970 By: I. McTaggart Cowan Bears: Their Biology and Management, Vol. 2, A Selection of Papers from the Second International Conference on Bear Research and Management, Calgary, Alberta, Canada, 6-9 November 1970. IUCN Publications New Series no. 23 (1972), pp. 343-367 International Association for Bear Research and Management
Wabusk of the Omushkegouk: Cree-Polar Bear (Ursus maritimus) Interactions in Northern Ontario By: Raynald Harvey Lemelin, Martha Dowsley, Brian Walmark, Franz Siebel, Louis Bird, George Hunter, Tommy Myles, Maurice Mack, Matthew Gull, Matthew Kakekaspan, The Washaho First Nation at Fort Severn and The Weenusk First Nation at Peawanuck Human Ecology, Vol. 38, No. 6 (DECEMBER 2010), pp. 803-815 Springer
MAX DELBRÜCK CENTER FOR MOLECULAR MEDICINE IN THE HELMHOLTZ ASSOCIATION
IMAGE: GRIZZLY BEARS' MUSCLES MANAGE TO SURVIVE HIBERNATION VIRTUALLY UNHARMED. RESEARCHERS ARE TRYING TO UNDERSTAND THE MECHANISMS BEHIND THIS ABILITY IN ORDER TO HELP BEDRIDDEN PATIENTS. view more
CREDIT: GOTTHARDT LAB, MDC
Grizzly bears spend many months in hibernation, but their muscles do not suffer from the lack of movement. In the journal "Scientific Reports", a team led by Michael Gotthardt reports on how they manage to do this. The grizzly bears' strategy could help prevent muscle atrophy in humans as well.
A grizzly bear only knows three seasons during the year. Its time of activity starts between March and May. Around September the bear begins to eat large quantities of food. And sometime between November and January, it falls into hibernation. From a physiological point of view, this is the strangest time of all. The bear's metabolism and heart rate drop rapidly. It excretes neither urine nor feces. The amount of nitrogen in the blood increases drastically and the bear becomes resistant to the hormone insulin.
A person could hardly survive this four-month phase in a healthy state. Afterwards, he or she would most likely have to cope with thromboses or psychological changes. Above all, the muscles would suffer from this prolonged period of disuse. Anyone who has ever had an arm or leg in a cast for a few weeks or has had to lie in bed for a long time due to an illness has probably experienced this.
A little sluggish, but otherwise fine
Not so the grizzly bear. In the spring, the bear wakes up from hibernation, perhaps still a bit sluggish at first, but otherwise well. Many scientists have long been interested in the bear's strategies for adapting to its three seasons.
A team led by Professor Michael Gotthardt, head of the Neuromuscular and Cardiovascular Cell Biology group at the Max Delbrueck Center for Molecular Medicine (MDC) in Berlin, has now investigated how the bear's muscles manage to survive hibernation virtually unharmed. The scientists from Berlin, Greifswald and the United States were particularly interested in the question of which genes in the bear's muscle cells are transcribed and converted into proteins, and what effect this has on the cells.
Understanding and copying the tricks of nature
"Muscle atrophy is a real human problem that occurs in many circumstances. We are still not very good at preventing it," says the lead author of the study, Dr. Douaa Mugahid, once a member of Gotthardt's research group and now a postdoctoral researcher in the laboratory of Professor Marc Kirschner of the Department of Systems Biology at Harvard Medical School in Boston.
"For me, the beauty of our work was to learn how nature has perfected a way to maintain muscle functions under the difficult conditions of hibernation," says Mugahid. "If we can better understand these strategies, we will be able to develop novel and non-intuitive methods to better prevent and treat muscle atrophy in patients."
Gene sequencing and mass spectrometry
To understand the bears' tricks, the team led by Mugahid and Gotthardt examined muscle samples from grizzly bears both during and between the times of hibernation, which they had received from Washington State University. "By combining cutting-edge sequencing techniques with mass spectrometry, we wanted to determine which genes and proteins are upregulated or shut down both during and between the times of hibernation," explains Gotthardt.
"This task proved to be tricky - because neither the full genome nor the proteome, i.e., the totality of all proteins of the grizzly bear, were known," says the MDC scientist. In a further step, he and his team compared the findings with observations of humans, mice and nematode worms.
Non-essential amino acids allowed muscle cells to grow
As the researchers reported in the journal "Scientific Reports", they found proteins in their experiments that strongly influence a bear's amino acid metabolism during hibernation. As a result, its muscle cells contain higher amounts of certain non-essential amino acids (NEAAs).
"In experiments with isolated muscle cells of humans and mice that exhibit muscle atrophy, cell growth could also be stimulated by NEAAs," says Gotthardt, adding that "it is known, however, from earlier clinical studies that the administration of amino acids in the form of pills or powders is not enough to prevent muscle atrophy in elderly or bedridden people."
"Obviously, it is important for the muscle to produce these amino acids itself - otherwise the amino acids might not reach the places where they are needed," speculates the MDC scientist. A therapeutic starting point, he says, could be the attempt to induce the human muscle to produce NEAAs itself by activating corresponding metabolic pathways with suitable agents during longer rest periods.
Tissue samples from bedridden patients
In order to find out which signaling pathways need to be activated in the muscle, Gotthardt and his team compared the activity of genes in grizzly bears, humans and mice. The required data came from elderly or bedridden patients and from mice suffering from muscle atrophy - for example, as a result of reduced movement after the application of a plaster cast. "We wanted to find out which genes are regulated differently between animals that hibernate and those that do not," explains Gotthardt.
However, the scientists came across a whole series of such genes. To narrow down the possible candidates that could prove to be a starting point for muscle atrophy therapy, the team subsequently carried out experiments with nematode worms. "In worms, individual genes can be deactivated relatively easily and one can quickly see what effects this has on muscle growth," explains Gotthardt.
A gene for circadian rhythms
With the help of these experiments, his team has now found a handful of genes whose influence they hope to further investigate in future experiments with mice. These include the genes Pdk4 and Serpinf1, which are involved in glucose and amino acid metabolism, and the gene Rora, which contributes to the development of circadian rhythms. "We will now examine the effects of deactivating these genes," says Gotthardt. "After all, they are only suitable as therapeutic targets if there are either limited side effects or none at all."
###
Literature
Douaa Mugahid et al. (2019): "Proteomic and Transcriptomic Changes in Hibernating Grizzly Bears Reveal Metabolic and Signaling Pathways that Protect against Muscle Atrophy," Scientific Reports, DOI: 10.1038/s41598-019-56007-8
Max Delbrueck Center for Molecular Medicine (MDC)
The Max Delbrueck Center for Molecular Medicine in the Helmholtz Association (MDC) was founded in Berlin in 1992. It is named for the German-American physicist Max Delbrueck, who was awarded the 1969 Nobel Prize in Physiology and Medicine. The MDC's mission is to study molecular mechanisms in order to understand the origins of disease and thus be able to diagnose, prevent, and fight it better and more effectively. In these efforts the MDC cooperates with Charite - Universitätsmedizin Berlin and the Berlin Institute of Health (BIH) as well as with national partners such as the German Center for Cardiovascular Research (DZHK) and numerous international research institutions. More than 1,600 staff and guests from nearly 60 countries work at the MDC, just under 1,300 of them in scientific research. The MDC is funded by the German Federal Ministry of Education and Research (90 percent) and the State of Berlin (10 percent), and is a member of the Helmholtz Association of German Research Centers. http://www.mdc-berlin.de
Two-thirds of the world's polar bears will be killed off by 2050 — and the entire population gone from Alaska — because of thinning sea ice from global warming in the Arctic, government scientists forecast Friday.
Only in the northern Canadian Arctic islands and the west coast of Greenland are any of the world's 16,000 polar bears expected to survive through the end of the century, said the U.S. Geological Survey, which is the scientific arm of the Interior Department.
As climate change thins sea ice around the Arctic, making travel by snowmobile during the spring precarious even for practiced hunters, one solution may be to borrow technology from the swampy Everglades of Florida.
Arctic Kingdom Marine Expeditions is reporting success in using airboats to guide tours to the floe edge outside Pond Inlet this summer.
The estimate is based on a study of national and international computer models keeping the period 1979-1999 as a base. An earlier report by the Intergovernmental Panel on Climate Change (IPCC) had found that sea loss was greater in the summer in Arctic Sea located north of Alaska, Canada and Asia.
The IPCC report had placed the blame on greenhouse gases and had said that unless these emissions were controlled, the Arctic Sea would almost disappear by the turn of the century.
About 40 percent of the floating ice that normally blankets the top of the world during the summer will be gone by 2050, says James Overland, an oceanographer at the National Oceanic and Atmospheric Administration's Pacific Marine Environmental Laboratory. Earlier studies had predicted it would be nearly a century before that much ice vanished.
"This is a major change," Overland said. "This is actually moving the threshold up.
"If you had asked me a few years ago, I would have said it wouldn't happen until 2070 or 2100," said Serreze, who was not involved in Overland's project.
Even a 40 percent loss of ice would be devastating to ice-dependent animals such as walruses and ringed seals, said Overland, who shared his data with federal officials considering an endangered-species listing for polar bears.
Gray whales will suffer if the ice-loving crustaceans they feed on disappear. But some commercially important fish species, like pollock and salmon, could thrive in warmer water — a possible boon for the Seattle-based fishing fleet that plies Alaska's Bering Sea. There are also hints, though, that the disappearance of ice would favor predators that undermine fisheries, Overland said.
Shipping will benefit if the Northwest Passage across the Canadian Arctic melts out each summer — as it did for the first time this year.
Of course that is why we are having the international race to declare sovereignty over the arctic because heck there is a silver lining to global warming after all.
"We think it's a great frontier ...." Fox says. "The belief is that about 25 percent of the world's remaining reserves are in the Arctic. And I think it's a major play for us."
Even the climate seemed to be cooperating with that major play. Polar ice retreated this summer from the spot where Shell plans to explore for oil.
Shell would hardly need its reinforced hulls, or rented Russian icebreakers.
The effects of burning fossil fuels today will extend long beyond the next couple of hundred years, possibly delaying the onset of Earth's next ice age, more properly called a glacial period, says researcher Toby Tyrrell of the University of Southampton in the United Kingdom.
