What 'animal family' do crocodile belong to and why characteristics that are common to this group of animals?

Crocodillians are an order of reptiles, which is the group above family. Crocodiles specifically come from the family Crocodylidae. The easiest way to distinguish the Crocodylidae from alligators and caiman is the jaw shape; Crocodylidae have "V" shaped jaws, and the latter two have "U" shaped jaws.