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Home* News and Stories → Spe­ci­es “polar bear” older than belie­ved so far

Spe­ci­es “polar bear” older than belie­ved so far

So far it has been assu­med that the spe­ci­es polar bear (Ursus mari­ti­mus) has a rather recent ori­gin in the upper Plei­sto­ce­ne, may­be 100.000 or maxi­mum 200.000 years ago. This would indi­ca­te a very clo­se rela­ti­ons­hip to brown bears and a quick adap­ti­on to the high arc­tic envi­ron­ment.

A stu­dy recent­ly publis­hed in Sci­ence has now indi­ca­ted a much older ori­gin for the spe­ci­es. The aut­hors sug­gest an evo­lu­tio­na­ry age of appro­xi­mate­ly 600.000 years (con­fi­dence inter­vall 338.000 to 934.000 years, mid- to lower Plei­sto­ce­ne). Older stu­dies are sup­po­sed to be mis­led by gene­ti­cal con­ta­mi­na­ti­on from cross-bree­ding, an error source belie­ved to be avoided in the new stu­dy.

Polar bears as a spe­ci­es have accord­in­gly had signi­fi­cant­ly more time to adapt from the sub-arc­tic habi­tat of brown bears to the high arc­tic. If this has any impli­ca­ti­ons for the adap­t­ati­on time of polar bears to recent chan­ges in envi­ron­ment and cli­ma­te remains an unans­we­red ques­ti­on at the time being.

Small polar bear fami­ly in Spits­ber­gen. Their ances­tors were alrea­dy roa­ming through the ice in mid-Plei­sto­ce­ne times.

Species polar bear older than believed so far - Polar bear family, Spitsbergen

Source: Sci­ence

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last modification: 2014-07-01 · copyright: Rolf Stange
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