The food web in this sea was complex and is not fully understood. Many of the animals were predators or scavengers, relying on other animals for food.

We are not certain about what some animals ate, but fossils can tell us part of the story. In rare cases, the remains of another animal can be found in the predator's mouth, throat or stomach.

For example:

Somemosasaur bones show giant shark (Cretoxyrhina) bite marks that have healed, suggesting that the shark hunted mosasaurs.

Several Xiphactinus specimens have been found with Gillicus that have been fossilized inside of them.