Streamlined Digger

Thrinaxodon was built for digging and hiding. The small near-mammal was thin and cylindrical (as far as any tetrapod can be cylindrical anyway) and had a head that was elongated rostrocaudally. This gave it a long skinny body overall and made it look somewhat weasel-like. The major exception to this was the large, but slender, canine-like face with its large canine teeth that appear almost like tusks. The large teeth were not helpful for digging in any specific way, however, the limbs were most built for burrowing. They were short and powerful for digging and burrowing out their homes, but still elongated enough to be suitable for propelling it through the underbrush of small ferns and cycads that populated its world. Given its ability to scurry, probable nocturnal nature, and large teeth, Thrinaxodon was at least omnivorous and most likely fed on insects, lizards, and possibly other near-mammals/mammals and dinosaur nestlings or eggs. Burrowing was an effective way for an animal like this to hide during the day while it ran around at night getting into those dinosaur nests, other near-mammal burrows, and catching nocturnal insets. Efficient as it was then, burrowing is still extremely efficient and useful for small mammals, such as mice and mink, and larger mammals like badgers and otters (River Otters get rather large). It is no wonder that animals like Thrinaxodon would have used burrows for protection. Imagine this small animal shimmying through the hardened soil tunnels!