Most constrictors hunt on the surface. The mole snake does its work below it, entering the tunnels of rodents and golden moles and killing them where they sleep. The head is small and pointed with a hardened rostral scale, the neck musculature disproportionately heavy, and the body cylindrical, a combination that suits pushing through soil and applying coils where there is no space to throw a wide loop.
Adults commonly reach 1.2 to 1.6 metres and occasionally exceed two, making them among the larger snakes of southern African grassland. Juveniles look like a different animal, patterned with dark zigzags and blotches that fade with age to a plain adult colour ranging from yellow-brown through red to almost black, with regional tendencies.
The species is non-venomous but is regularly killed on sight, partly because large dark individuals are taken for cobras. Males fight each other in the breeding season with sustained biting, leaving scarred heads. Farmers who leave them alone gain a rodent control agent that works in places no cat or terrier can reach.