{"id":564,"date":"2025-03-11T07:00:50","date_gmt":"2025-03-11T08:00:50","guid":{"rendered":"http:\/\/guruapproved.com\/?p=564"},"modified":"2025-03-18T13:19:25","modified_gmt":"2025-03-18T13:19:25","slug":"polar-bear-history-hazards-and-hair","status":"publish","type":"post","link":"http:\/\/guruapproved.com\/index.php\/2025\/03\/11\/polar-bear-history-hazards-and-hair\/","title":{"rendered":"Polar Bear History, Hazards and Hair"},"content":{"rendered":"
\"Adobe<\/p>\n

The Western Hudson Bay polar bears are the most studied polar bear population in the Arctic. They are also the ones that have been most extensively filmed, photographed and marveled at, thanks to the tourism industry that has developed around the bears in Churchill, Manitoba, Canada.<\/p>\n<\/div>\n

Symbols of courage, resilience and strength, polar bears<\/a> have been featured in decorative arts for centuries. Today, they may be best known as emblems of climate change,<\/a> \u201ccharismatic victims\u201d used to inspire people to care about our warming Earth. But not only does Ursus maritimus<\/em> persist in our consciousness, polar bears\u2014the largest bear on the planet\u2014continue to astound us with their creativity, intelligence, patience and physiology.<\/p>\n

For example, a recent analysis of ancient DNA from a 100,000-year-old polar bear has revealed that extensive hybridization between polar bears and brown bears<\/a> occurred during the last warm interglacial period in the Pleistocene, leaving a surprising amount of polar bear ancestry in the genomes of all living brown bears<\/a> today.<\/p>\n

In another new finding, the secret to how polar bears manage to survive and thrive in one of the world\u2019s most punishing climates comes to light: greasy hair.<\/p>\n

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A polar bear\u2019s skull can teach us about the adaptations that help polar bears survive in the harsh Arctic environment and how the animals have evolved over time. \u00a9Klaus Rassinger und Gerhard Cammerer, Museum Wiesbaden, Wikimedia Commons<\/a><\/p>\n<\/div>\n

Ancient hybridization with brown bears<\/strong><\/h3>\n

Although polar bears<\/a> and brown bears are distinct species with striking differences in appearance, behavior and habitats, they are closely related and can readily hybridize when their ranges overlap. Reports of hybrids<\/a> have increased in recent years as the climate warms and disappearing sea ice forces polar bears onto Arctic coasts, while brown bears expand their range northward.<\/a><\/p>\n

Previous studies of ancient DNA have shown that admixture has occurred in certain populations of brown bears at least four different times between about 15,000 and 25,000 years ago. In all cases, the direction of gene flow was from polar bears into brown bears. These mixed individuals, if they survived, did so as brown bears; perhaps because they would have had difficulty hunting successfully on the sea ice if they were not completely white. Polar bears have always been a small population with not much genetic diversity.<\/p>\n

In 2009, the skull of a juvenile polar bear\u2014nicknamed \u201cBruno\u201d (although DNA analysis later showed it to be female)\u2014was found on the coast of the Beaufort Sea in Arctic Alaska. An analysis by scientists from the University of California, Santa Cruz, established that Bruno belonged to a polar bear population that was ancestral to living polar bears. Finding Bruno\u2019s skull was serendipitous. Since polar bears spend most of their lives at sea, coming across any polar bear remains is extremely unusual. Bruno\u2019s is the only ancient polar bear skull that\u2019s ever been recorded\u2014and the only ancient polar bear bone known from North America.<\/p>\n

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Polar bear ancestry accounts for as much as 10% of the genomes of brown bears living today, indicating that ancient hybridization between the two species occurred, with gene flow primarily moving from polar bears to brown bears.<\/p>\n<\/div>\n

At some point, probably around 125,000 years ago, the polar bear lineage leading to Bruno and the brown bear lineage leading to all living brown bears crossed paths and hybridized. As a result of accessibility to Bruno\u2019s paleogenome, the California researchers learned that polar bear ancestry accounts for as much as 10% of the genomes of brown bears living today. Their results were published in June 2022 in the journal Nature Ecology & Evolution. <\/em><\/a><\/p>\n

This study did find some evidence of possible gene flow from brown bears into Bruno\u2019s lineage, but the absence of admixture in polar bears today supports the idea that brown bear ancestry reduces a bear\u2019s fitness for life as a polar bear. After diverging from brown bears about 500,000 years ago, polar bears evolved into highly specialized hunters of marine mammals on the Arctic sea ice. Brown bears, in contrast, are generalists ranging widely across Asia, Europe and North America.<\/p>\n

Climatic shifts that have brought polar bears and brown bears together in the past include glacial periods when sea ice was more extensive, allowing polar bears to mix with brown bears in southeast Alaska, the Kuril Islands in the Russian Far East and even Ireland.<\/a> The brown bears in these locations (now extinct in Ireland) acquired additional polar bear genes on top of the ancient admixture revealed by Bruno\u2019s genome. As for what brown bears might have gained from their polar bear ancestry, scientists can only speculate. It\u2019s possible that brown bears got something cool from polar bears, but no one knows for sure\u2014yet.<\/p>\n

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Unlike polar bears that are highly specialized hunters of marine mammals on the Arctic sea ice, brown bears are generalists that range widely across Asia, Europe and North America. This bear is munching on blueberries.<\/p>\n<\/div>\n

Bruno lived during a time of changing climate after the peak of a warm interglacial period when temperatures and sea levels were considerably higher than they are now. Similar conditions can be expected in the future because of rapid climate change, driven by the burning of fossil fuels<\/a> and other human activities. As Arctic sea ice declines, many polar bear populations are already struggling to survive. If the rapid, unnatural and severe human-caused warming of the Arctic we are documenting today continues unabated, it is uncertain whether polar bears will have a sea-ice habitat to return to and survive genetically, say the scientists.<\/p>\n

However, we shouldn\u2019t be surprised to see gene flow occurring between what we think of as different species happening again today as the climate changes and brown bears and polar bears overlap and encounter each other again in the wild. Understanding how past changes in the climate drove interactions between organisms is critical to predicting how current changes will create new admixtures, increase disease transmission, or impact natural resources or society, conclude the scientists.<\/p>\n

Fur with anti-icing properties<\/strong><\/h3>\n

After some \u201cpolar sleuthing,\u201d which involved scrutiny of hair collected from six polar bears in the wild, scientists from Trinity College Dublin\u2019s School of Chemistry and AMBER Research Center in Ireland and the University of Bergen in Norway found that hair sebum (or grease)\u2014which is made up of cholesterol, diacylglycerols and fatty acids\u2014makes it very hard for ice to attach to polar bears\u2019 fur. These findings were published in the international journal Science Advances<\/em><\/a> in January 2025.<\/p>\n

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Sebum, fatty lubricant matter secreted by sebaceous glands of the skin, found in polar bear fur is the key component that gives the bears their anti-icing properties, which come in handy when hunting seals on ice platforms.<\/p>\n<\/div>\n

To conduct this study, the researchers measured ice adhesion strength, which is a useful measure of how well ice sticks to fur; hydrophobicity, which dictates whether water can be shed before it freezes; and freezing delay time, which simply shows how long it takes for a drop of water to freeze at certain temperatures on a given surface. They then compared the performance of the polar bear hair with that of human hair and two types of specialist, human-made \u201cski skins.\u201d<\/p>\n

The sebum quickly jumped out as being the key component giving the anti-icing effect, since the adhesion strength was greatly impacted when the hair was washed. When washed and the grease largely removed from it, polar bear hair performed similarly to human hair, to which ice sticks easily whether it is washed or greasy. In contrast, unwashed, greasy polar bear hair made it much harder for ice to stick.<\/p>\n

That finding led the team to perform a detailed chemical analysis of polar bear sebum. As well as identifying its key components, the scientists were surprised to find squalene was absent. This fatty metabolite is present in human hair and in the hair of other aquatic animals, such as sea otters,<\/a> which suggests its absence in polar bear hair is very important from an anti-icing perspective.<\/p>\n

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Despite spending extensive periods in water at subzero temperatures, polar bears don\u2019t suffer from ice accumulation. Their \u201cfur grease\u201d provides a natural route for easily shedding ice.<\/p>\n<\/div>\n

This work not only represents the first study of the composition of polar bear fur sebum, but it also resolves the question of why polar bears don\u2019t suffer from ice accumulation. Despite having thick layers of insulating blubber and fur and spending extensive periods in water at subzero temperatures, polar bears have a natural route in their fur for easily shedding ice when it forms.<\/p>\n

These natural lipid coatings produced by polar bears will help us develop new, more sustainable, anti-icing coatings that may replace problematic forever chemicals, such as PFAS,<\/a> that have been previously used. They may also have a suite of unrelated applications, with a similar concoction of artificially-made sebum promising to be useful as an anti-ice surface coating or in next-gen ski skins used by skiers and snowboarders.<\/p>\n

This isn\u2019t the first time that animals living in polar habitats have emerged as a source of inspiration for the development of new anti-icing materials. For example, it was recently discovered that the hierarchical structure<\/a> of Gentoo penguin<\/a> feathers gives the birds anti-icing properties.<\/p>\n

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The hierarchical structure of Gentoo penguin feathers afford the birds anti-icing properties that rely on feather structure rather than on a preening oil coating.<\/p>\n<\/div>\n

These interesting discoveries also help us better understand the ecology of both polar bears and native Inuit populations. One of the polar bear\u2019s main hunting strategies is \u201cstill hunting,\u201d where the animal remains motionless beside a breathing hole on sea ice waiting for seals to surface. Still hunting frequently develops into an \u201caquatic stalk,\u201d with the polar bear using its hind paws to slide into the water to pursue its prey; and the lower the ice adhesion, the less noise generated and the faster and quieter the slide.<\/p>\n

Inuit people optimize their hunting strategies to mimic the polar bear method of still hunting. Inuit hunting stools are sometimes shod with polar bear fur on the feet to avoid noise when moving on the ice. And people sometimes wear \u201cpolar bear trousers,\u201d ensuring the entire contact area with the ice is covered in low-ice-adhesion polar bear fur for optimal noise reduction.<\/p>\n

Notably, the traditional Inuit preparation method protects the sebum on the fur by ensuring the hair-covered side of the skin is not washed. This is unlike, for example, a fox skin, which would traditionally be cleaned by rubbing the hair side with soapstone or dry clay.<\/p>\n

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Inuit people model their hunting strategies on the polar bear method of \u201cstill hunting.\u201d They sometimes wear trousers made from polar bear fur, ensuring that their contact area with the ice is covered in a low-ice-adhesion material that is also optimal for noise reduction.<\/p>\n<\/div>\n

Polar bear population declines due to \u201cenergy deficit\u201d<\/strong><\/h3>\n

Unfortunately, such fun and informative discoveries about polar bears may not go on forever. In another January 2025 study, this time published in the journal Science,<\/em><\/a> researchers from the University of Toronto Scarborough developed a model that demonstrates that population decline in polar bears is the result of the bears not getting enough energy, and that\u2019s due to a lack of food caused by shorter hunting seasons on dwindling sea ice. A loss of sea ice means bears spend less time hunting seals and more time fasting on land, which negatively affects the bears\u2019 energy balance, leading to reduced reproduction and cub survival and, ultimately, population decline.<\/p>\n

The \u201cbio-energetic\u201d model developed by the researchers tracks the amount of energy the bears are currently getting from hunting seals and the amount of energy they need to grow and reproduce. What\u2019s unique about the model is that it follows the full life cycle of individual polar bears\u2014from cub to adulthood\u2014and compares it to four decades of monitoring data from the Western Hudson Bay polar bear population<\/a> between 1979 and 2021. During this period, the polar bear population in this region has declined by nearly 50%. The monitoring data shows that the average size of polar bears is also in decline. The body mass of adult females has dropped by 86 pounds and that of one-year-old cubs by 47 pounds over a 37-year period.<\/p>\n

The researchers\u2019 model provides a close match to the monitoring data, meaning it provides an accurate assessment of what is happening and will continue to happen to the polar bear population if it keeps experiencing sea-ice loss and a greater amount of time in energy deficit. The model, however, goes one step further than saying there\u2019s a correlation between declining sea ice and population decline. It provides a mechanism that shows what happens when there is less ice, less feeding time and less energy overall. When the numbers are run, there\u2019s a near one-to-one match to what\u2019s seen in real life.<\/p>\n

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Polar bear cubs face the brunt of climate-induced challenges. Shorter hunting periods cause mothers to produce less milk, which jeopardizes their young ones\u2019 survival. Mothers now are also having fewer cubs.<\/p>\n<\/div>\n

Sadly, cubs face the brunt of these climate-induced challenges. Shorter hunting periods result in mothers producing less milk, which jeopardizes cub survival. The cubs face reduced survival rates during their first fasting period if they fail to gain enough weight.<\/p>\n

Mothers are also having fewer cubs. Monitoring data shows cub litter sizes have dropped 11% compared to almost 40 years ago, and mothers are keeping their cubs longer because they aren\u2019t strong enough to live on their own. And, simply put, the survival of cubs directly impacts the survival of the population.<\/p>\n

Western Hudson Bay has long been considered a bellwether for polar bear populations globally; and as the Arctic warms at a rate four times faster than the global average,<\/a> the researchers warn of similar declines in other polar bear populations. This model basically describes their future, they say.<\/p>\n

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Many Inuit hunters consider polar bears to be the most intelligent animal in the Arctic. For the rest of us, polar bears represent courage, resilience and strength. The saying is trite but true: polar bears are on thin ice. Let\u2019s not lose them on our watch.<\/p>\n<\/div>\n

Polar bear proficiencies and product ideas<\/strong><\/h3>\n

An Arctic icon, polar bears have also played roles in art, conservation and politics. We\u2019re lucky to have them still among us. Bruno\u2019s ancient skull has given us insights not only into present-day polar bear physiology but that of all living brown bears. And today\u2019s polar bears have provided inspiration for the creation of new products for anti-icing and better traction<\/a> on ice and snow.<\/p>\n

But the warming of the Earth<\/a> that our activities have caused could spell the end for polar bears. Let\u2019s not lose them now\u2014on our watch.<\/p>\n

Here\u2019s to finding your true places and natural habitats,<\/span><\/p>\n

Candy<\/span><\/p>\n

 <\/p>\n

The post Polar Bear History, Hazards and Hair<\/a> first appeared on Good Nature Travel Blog<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"

The Western Hudson Bay polar bears are the most studied polar bear population in the Arctic. They are also the ones that have been most extensively filmed, photographed and marveled at, thanks to the tourism industry that has developed around the bears in Churchill, Manitoba, Canada. Symbols of courage, resilience […]<\/p>\n","protected":false},"author":1,"featured_media":566,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9],"tags":[],"class_list":["post-564","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-wildlife"],"_links":{"self":[{"href":"http:\/\/guruapproved.com\/index.php\/wp-json\/wp\/v2\/posts\/564","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/guruapproved.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/guruapproved.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/guruapproved.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/guruapproved.com\/index.php\/wp-json\/wp\/v2\/comments?post=564"}],"version-history":[{"count":3,"href":"http:\/\/guruapproved.com\/index.php\/wp-json\/wp\/v2\/posts\/564\/revisions"}],"predecessor-version":[{"id":577,"href":"http:\/\/guruapproved.com\/index.php\/wp-json\/wp\/v2\/posts\/564\/revisions\/577"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/guruapproved.com\/index.php\/wp-json\/wp\/v2\/media\/566"}],"wp:attachment":[{"href":"http:\/\/guruapproved.com\/index.php\/wp-json\/wp\/v2\/media?parent=564"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/guruapproved.com\/index.php\/wp-json\/wp\/v2\/categories?post=564"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/guruapproved.com\/index.php\/wp-json\/wp\/v2\/tags?post=564"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}