Hyaenodontidae - General Characteristics

General Characteristics

Characterized by long skulls, slender jaws, slim bodies, and a tendency to walk on their toes rather than flat-footed (plantigrade), they generally ranged in size from 30 to 140 cm at the shoulder. While Hyaenodon gigas, the largest Hyaenodon species was as much as 1.4 m high at the shoulder, 10 feet long and weighed about 500 kg, most were in the 5–15 kg range, equivalent to a mid-sized dog. Fossil evidence of their skulls shows that they had a particularly acute sense of smell, while their teeth were adapted for shearing, rather than crushing.

Because of their size range, it is probable that different species hunted in different ways and allowed them to fill many different predatory niches. Smaller ones would hunt in packs during the night like wolves, and bigger, fiercer ones would hunt alone during the daylight, using their sheer size and their mighty jaws as their principal weapon. The carnassials in a hyaenodontid are the second upper and third lower molars.