Dunkleosteus looked like the violent brute it was: powerfully built and armour-plated round its head. It was streamlined and shark-like. Dunkleosteus lacked true teeth, instead it had two long bony blades that could snap and crush almost anything. Pigment cells suggest Dunkleosteus had dark colours on its back and was silvery on its belly.
This fish was anything but picky with its food. It ate fish, sharks and even its own kind. And it seems that Dunkleosteus suffered from indigestion as a result: its fossils are often associated with regurgitated, semi-digested remains of fish.
Dunkleosteus may have been one of the earliest animals to exist as male or female, meaning that pairs of fish had to mate physically.