Tuesday, February 5, 2008

NOT SO CUDDLY BEAR




Previously, scientists thought cave bears were just vegetarians, evoking an image of gentle giants that fed solely on berries and roots.
Now bones from the Carpathians — the mountains where Dracula supposedly dwelt — suggest cave bears could have also been carnivores, and possibly even cannibals.
Bad to the bone
Cave bears (Ursus spelaeus) are named after the places where their bones are commonly found — caves across Europe. They died out roughly 20,000 years ago, when ice dominated the Northern Hemisphere.
For the past 30 years, studies of their skulls, jaws and teeth suggested cave bears might have been largely herbivorous.

In addition, the bones of central and western European cave bears matched those of vegetarians in having low levels of nitrogen-15, whose atomic nucleus has one more neutron than common nitrogen-14 does.
Animals accumulate nitrogen-15 in their bodies, and animals that eat animals — that is, carnivores — build up more nitrogen-15 than herbivores do.
Still, black bears and brown bears are omnivores. This suggested that although some cave bears were largely vegetarian, others might have been more carnivorous.
New data from the Pestera cu Oase ("Cave with Bones") in the southwestern tip of the Carpathian mountains in Romania now hints most of its cave bears were significantly carnivorous, due to their high nitrogen-15 levels.

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