24-16 million years ago, late Oligocene - early Miocene
The Cleaver-headed Crocodile is one of the largest of an extinct group of crocodiles called mekosuchines. It lived in and around pools of fresh water bounded by wet forest, where it ambushed its prey - consisting of anything this frightening reptile could catch, from insects to the largest marsupials. It would have used its large, bladed teeth to slice into its prey.
Relationships between mekosuchine crocodiles and living crocodiles are unclear, so it is hard to say which crocodile is the Cleaver-headed Crocodile's closest living relative.
Fossils of the Cleaver-headed Crocodile have been found at Riversleigh in north-western Queensland. They include a partial skull, jaws and other bones.
Did you know?
The Cleaver-headed Crocodile had a very deep skull, resembling those of flesh-eating dinosaurs.