At between eleven and thirteen meters long it goes without saying that Purussaurus was an apex predator capable of attacking large prey. As a caiman crocodile, Purussaurus had an extremely stout and robust skull that housed large conical teeth suited for gripping and holding onto powerful prey.
Purussaurus is one of the growing number of contenders for the epithet of largest crocodile. Other crocs to obtain giant sizes include Sarcosuchus, Deinosuchus, Rhamphosuchus, as well as Gryposuchus and Mourasuchus, which are known from similar times and locations as Purussaurus.