Interspecies Sex: Evolution's Hidden Secret?

Killed by a hunter last month in the Canadian Arctic, this male bear was confirmed via DNA analysis last week to be half grizzly, half polar bear.












The act of mating with a species other than your own may not be as ill advised or peculiar as it seems.

Recent research indicates that hybridization is not only widespread in nature but it might also spawn many more new species than previously thought.

A growing number of studies has been presented as evidence that two animal species can combine to produce a third, sexually viable species in a process known as hybrid speciation. Newly identified examples include both insects and fish.

This evolutionary process, while known to be common in plants, has long been considered extremely rare among animals.

Animals are generally thought to evolve the opposite way, when a single species gradually splits into two over many generations.

But some scientists now believe that the behavior that has been called animals' sexual blunders could be an important force in their evolution.