They are divided into groups according to their diet
The dogs were then given a number of different tests. Measurements of the isotopes of carbon 13 and nitrogen15 were used to place each animal in one of three feeding-based groups (A, B or C). Group A was largely similar to older wolves and was fed a diet of mainly large animals such as megafauna and mammoths. The dogs in group B, however, had a lower N15 measurement indicative of a low protein intake and a broad diet.