Hoplophoneus is an extinct genus of carnivorous mammals that lived in North America during the Eocene-Oligocene (38-33,3 million years ago).
It was the size of a leopard, with a stocky body and short legs, and about 40 kg in weight.
Also had a groove in the lower jaw where they settled long saber-like canines of the upper jaw, but never to be considered a saber tooth. Experts believe that this mammal patiently perched in the branches of the trees and then jumping on their prey and causing fatal injuries with long, sharp fangs.
The Hoplophoneus was similar to cats, although they were not. The structure of the inner ear bones are different, the cats have an external structure called the auditory bulla separated by a partition into two chambers, the lack nimrávidos noise.
Curiosity: As Eusmilus, the Hoplophoneus, had teeth that hid when not in use, the cat kept his fangs in special bags adapted in the lower jaw .