According to the University of Florida, crocodiles have ears; however, they do not have visible external parts like mammals. Crocodiles have slits on the top of their heads that lead to the inner ears. When a crocodile submerges, the slits are covered by flaps of skin that protect the eardrums.
The San Diego Zoo indicates that a crocodile's sense of hearing is excellent. Since their ears and eyes are located high on their heads, crocodiles can remain mostly underwater and still hear and see well when hunting, UF indicates. Their hearing is so sensitive that crocodiles are able to hear sounds made by baby crocodiles before they have hatched.