Mosasaurs are huge, seagoing lizards from
the Cretaceous. They
are related to modern monitor lizards,
but have flippers in place
of feet. They can open their mouths to
a huge gape, so that any
adult mosasaur can swallow human-sized
prey whole. Mosasaurs
may be treated as non-intelligent crocodilians,
some of them being
adapted to shell-crushing and all of them
adapted to an aquatic
existence. They have from 7 to 13 HD.