<p><a href="http://blogs.discovermagazine.com/notrocketscience/files/2012/04/Polar_bear.jpg" title=""></a></p><div class="vert-display-toggle collapsible relative flex flex-col items-center "><div class="vert-unit mt-4 mb-3 top-20"><div ad-type="mobile-desktop" class="ad-wrapper vert min-h-boombox flex items-start justify-center" data-ad-mapping="inline" data-ad-slot="Discover/inline-ad" id="div-inline-ad-0"></div></div><span aria-label="Advertisement" class="text-ad mt-1 text-[11px] uppercase">Advertisement</span></div><figure class="fr-image-container fr-full"><img srcset="https://cdn.discovermagazine.com/assets/image/12553/Polar_bear-s.webp 480w, https://cdn.discovermagazine.com/assets/image/12553/Polar_bear-m.webp 660w" sizes="(max-width: 480px) 480px, 660px" src="https://cdn.discovermagazine.com/assets/image/12553/Polar_bear-s.jpg" title="Polar_bear.jpg" loading="lazy" data-id="12553"><figcaption class="fr-figcaption"><p class="fr-caption"></p></figcaption></figure><p> Earlier this year, <a href="http://blogs.discovermagazine.com/notrocketscience/2012/04/19/polar-bear-origins-revised-%E2%80%93-they%E2%80%99re-older-and-more-distinct-than-we-thought/" title="">I wrote about a new study</a></p><p> showing that polar bears split off from brown bears around 600,000 years ago – already making them four times older than previously thought. Now, a new study pushes the date of that split back even further, to between 4 and 5 million years ago. The exact date is probably going to shift again in the future, and if anything, it’s the least interesting bit of the new paper. Webb Miller, Stephan Schuster and Charlotte Lindqvist have taken a whirlwind look at the history of the polar bear. For a start, they sequenced its genome – that detail would be the centrepiece of other papers, but gets mentioned halfway through this one. They started looking at the genetic changes that have made polar bears lords of the Arctic, and they reconstructed the bears’ population history across the many climate upheavals it must have lived through. Finally, they found evidence that polar bears carry a lot of brown bear DNA in their genome (and vice versa) – a sure sign that the two species repeatedly bred with each other after diverging, in much the same way that our ancestors <a href="http://blogs.discovermagazine.com/notrocketscience/2011/09/12/humans-and-neanderthals-had-sex-but-not-very-often/" title="">had sex with Neanderthals and other ancient humans</a></p><div data-embedid="dcfb67aa-fdf4-4a19-b4c7-75c497a8de9c" id="insticator-embed-temp"></div><p>. I’ve written about the study for The Scientist. <a href="http://the-scientist.com/2012/07/23/the-polar-bears-prehistoric-past/" title="">Head over there for the full story.</a></p><p><strong>Photo </strong>by <a href="http://en.wikipedia.org/wiki/File:Polar_Bear_-_Alaska.jpg" title="">Alan Wilson</a></p>

Discover polar bear origins and their surprising history with brown bears, revealing genetic changes over millions of years.

Planet Earth

Revising the polar bear's evolutionary past... again 

Article

News

Ed Yong

Science

Earlier this year, I wrote about a new study showing that polar bears split off from brown bears around 600,000 years ago – already making them four times older than previously thought. Now, a new study pushes the date of that split back even further, to between 4 and 5 million years ago. The exact date is probably going to shift again in the future, and if anything, it’s the least interesting bit of the new paper. Webb Miller, Stephan Schuster and Charlotte Lindqvist have taken a whirlwind look at the history of the polar bear. For a start, they sequenced its genome – that detail would be the centrepiece of other papers, but gets mentioned halfway through this one. They started looking at the genetic changes that have made polar bears lords of the Arctic, and they reconstructed the bears’ population history across the many climate upheavals it must have lived through. Finally, they found evidence that polar bears carry a lot of brown bear DNA in their genome (and vice versa) – a sure sign that the two species repeatedly bred with each other after diverging, in much the same way that our ancestors had sex with Neanderthals and other ancient humans . I’ve written about the study for The Scientist. Head over there for the full story. Photo by Alan Wilson

Discover Magazine’s award-winning journalism inspires and informs, delivering thought-provoking content that sparks meaningful conversations. With a focus on groundbreaking developments in science, technology, and the world around us, Discover highlights the impact of these innovations on our daily lives.

再次修订北极熊的进化历史…

新闻简报

Ed Yong

逃过灭绝的史前树木——银杏等至今仍繁茂生长

三种新发现的蟾蜍以奇异的进化方式产下活体幼崽

弓头鲸可活到200岁，其DNA可能蕴含长寿的秘密

切尔诺贝利的狗神秘变蓝，但辐射并非罪魁祸首

深海发现食肉死亡球海绵及其他新物种

这些吸血鬼鹿拥有三英寸长的獠牙而非鹿角来抵御对手

在寻找“耐力号”沉船时，意外发现了一个隐藏的鱼类社区

吸血蜘蛛痴迷于人类血液，通过扑向蚊子来饱餐一顿

最稀有的海洋动物及其他6种神秘潜伏在深海的难以捉摸的生物

冰岛首次发现蚊子，可能与气候变化有关

这些蝙蝠在紫外光下会发出绿光，但原因仍然是个谜

不再是“料理鼠王”——芝加哥鼠洞实则被一只松鼠压扁

蝠鲼潜入近4000英尺深的海洋——不是为了觅食，而是为了寻找方向

鲸鱼和海豚为何会搁浅，痴呆症是罪魁祸首吗？

狗如何看世界？它们确实能看到颜色，但更关注我们

保持好奇

加入我们的列表

订阅杂志