SRD:Dire Bear

=DIRE BEAR=

The omnivorous dire bear usually does not bother creatures that try to avoid it, but will aggressively defend a kill or other source of food. It will not hesitate to rip apart anything that might contain something edible.

A typical dire bear is 12 feet long and weighs as much as 8,000 pounds.

Combat
A dire bear attacks by tearing at opponents with its claws.

Improved Grab (Ex): To use this ability, a dire bear must hit with a claw attack. It can then attempt to start a grapple as a free action without provoking an attack of opportunity.

See Wikipedia Entry: Cave Bear