Biarmosuchus was a medium-sized predator, similar in size to a large dog, grew up to 1.5–2 m in length with a skull length 15 cm (immature) to 21 cm.It was a lightly built, probably agile animal that would have fed on smaller tetrapods. Their legs are quite long, and the animals were probably quite agile in spite of their size. A large opening for the eye and a small temple opening common in primitive mammal-like reptiles, this lends to a weak bite but how it ate is pure speculation. The teeth contained eight small incisors on the palate, followed by a canine tooth and a further five canine teeth. So together the species contained fourteen upper teeth and twelve lower teeth of small size (Kemp 1982).