November 4, 2009 | David F. Coppedge

Polar Bears and Grizzlies Hybridize

What do you get when you cross a polar bear with a grizzly bear?  It’s not a joke; look at the BBC News and see.  You get bears with mixed shades of fur and a blend of characteristics.  Live Science also commented on the BBC report.
    Scientists have known that these species can hybridize, but the birth of mixed cubs in a German zoo allowed the first-ever study of them.  The blending of traits extends from behavior down to the individual hairs.
    Only one hybrid is known in the wild; a few others have occurred in captivity.  The male hybrid appears to be sterile, but scientists are trying to determine if the female hybrid is capable of bearing offspring.

Hybrids are common in plants and animals.  This is nothing all that unusual.  It attracts attention because of the large size of the animals and their distinctive colorations.  Creationists commonly believe that most bears are descendants of a single bear “kind” or baramin.  That’s not evolution in the sense Darwin used the word (common ancestry of all life by unguided processes of variation and selection).  It’s just a sorting out of traits.  The sorting persists according to adaptation to the local environment.  For instance, thick hair on Alaskan dogs helps them survive the cold winter, even though all domestic dogs are the same species.  That kind of “natural selection” is not controversial.  The genetic information was already present.  Coming up with a dog from bacteria is another issue altogether.

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Categories: Genetics, Mammals

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