This article makes them sound like the mimics from Prey:
Armadillos have poor eyesight but a keen sense of hearing, so [the hunter] stealthily sweeps the area with a heat-sensing scope to pick up patches of body heat he can sneak up on....In the pitch dark, [the hunter] adroitly shoulders his rifle and levels it at the object. “That looks like one!” he mutters. It turns out to be a fuse box. Another candidate, again aimed at with the gun, reveals itself as a rock.In this town besieged by armadillos, anything with a passing similarity to the armored nemesis is under suspicion.