Tag Archives: bears

New genetics paper is not about whether climate change causes polar bear hybrids

A new paper on the evolutionary history of bears (Bears breed across species borders: Kumar et al. 2017) has concluded that hybridization is common and natural among all species of ursids. And while some media outlets (e.g. DailyMail) have framed this as surprisingly convincing proof that experts were wrong to claim that climate change is the cause of recent polar bear X grizzly hybrids, definitive evidence against that interpretation has been available for years to anyone who bothered to look: see my recent “Five facts that challenge hybridization nonsense.”

This genetic evidence is just a cherry on top of the rest but will help get the paper the media attention the authors crave.

Polar bear X grizzly hybrids were known long before climate change and sea ice decline became an issue. See also previous posts here, here, and here. In fact, as I’ve pointed out, “most polar bear hybrids said to exist have not been confirmed by DNA testing” (including virtually all of the bears specialist Andrew Derocher claimed were hybrids, including the latest one from 2016 that prompted such gems as “Love in the time of climate change”).

pizzly_andrewderocher_300dpi_2017 paper

A polar bear X grizzly hybrid, see Kumar et al. 2017. Photo by A. Derocher.

In my opinion, the most important conclusion of this paper is that occasional but widespread hybridization among bears is why it has been so hard to say with confidence when polar bears arose (which I addressed years ago, in my Polar bear evolution series: Part 1, Part 2, and Part 3). You cannot use traditional methods of pinpointing the timing of speciation events from genetic data if one or more of the species have hybridized (traded genes). See the long, fuzzy “divergence times” for bears in the image below from the Kumar paper.

Kumar et al 2017 hybridization in bear evolution_fig 5

From Kumar et al. 2017, Fig. 5: “The scale bar shows divergence times in million years and 95% confidence intervals for divergence times [speciation events] are shown as shadings.”

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WWF and the International Bear Conference

The 24th International Conference on Bear Research and Management is coming up mid-month (12-16 June, 2016) in Anchorage, Alaska, and local media outlets are already gearing up. This conference is about all species of bears but the Arctic icon is apt to get most of the attention.

APM_The Science of Bears_June 7 2016 radio screencap_at 5 June marked


First up on the media roster appears to be an APRN Talk of Alaska radio talk show entitled The Science of Bears that will feature, among others, Steve Amstrup (spokesperson for Polar Bears International, of “Save Our Sea Ice” fame) and Margaret Williams (WWF, with a Masters in Environmental Studies), scheduled for Tuesday, June 7 at 10:00 AM Alaska time (that’s 11 AM Pacific).

Calls will be taken from the public and comments via email are invited (see below). It could be worth a listen, so mark your calendars. I’ll post a link to the audio podcast here if and when one gets published.

As for the ethics of such a close relationship of international bear scientists with the environmental activists at WWFone of the richest ‘charities’ around (and one might suppose, plans to stay that way), you’ll have to make up your own mind. Maybe the radio host will ask…

UPDATE 8 May 2016: Here’s the link to the podcast of this Talk of Alaska program from yesterday, which is provided in iTunes format (if you don’t have an iPhone or Apple tablet, you’ll need to down the iTunes program to your PC – a link for which is provided automatically. I did it and it works just fine. On the list of programs provided at the link, just click on the forward arrow to the left of “The Science of Bears”): https://itunes.apple.com/podcast/talk-of-alaska/id264469515?mt=2
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