A graveyard of huge marine reptile fossils was assumed to be the site of a massive die-off. It may have actually been a maternity ward.

Scientists have uncovered new clues about a curious fossil site in Nevada, a graveyard for dozens of giant marine reptiles. Instead of the site of a massive die-off as suspected, it might have been an ancient maternity ward where the creatures came to give birth. 

The site is famous for its fossils from giant ichthyosaurs - reptiles that dominated the ancient seas and could grow up to the size of a school bus. The creatures - the name means fish lizard - were underwater predators with large paddle-shaped flippers and long jaws full of teeth.

Since the ichthyosaur bones in Nevada were excavated in the 1950s, many paleontologists have investigated how all these creatures could have died together. Now, researchers have proposed a different theory in a study published Monday in the journal Current Biology.