relevant part of the linked article....

Seals are the bears' preferred prey. In spring, after emerging from
hibernation, they usually eat the whole seal, though later in the year
they
will often slit the animal open and simply eat the fat.  <A
HREF="http://news.bbc.co.uk/hi/english/sci/tech/newsid_906000/906832.stm">Clic
k here: BBC News | SCI/TECH | Scientists test sex-change bears
</A>