Adult Archeotherium had huge temporalis muscles, but they were normal-sized in juveniles and only developed as the animal matured. This suggests the expanded cheekbones and extreme jaw strength of the genus may have been involved in adult social behavior more than eating. It is also possible that younger animals had softer diets, or Archaeotherium had significant parental care.
The adult Archeotherium exhibited significantly larger temporalis muscles compared to juveniles, which increased as the animal matured. This suggests that the distinctive cheekbones and powerful jaws of the genus may have played a more prominent role in adult social interactions rather than foraging. Alternatively, younger animals might have had softer diets or received significant parental care.