It is the northernmost home of the armadillo, ocelot, jaguar, red and grey cats, and the spiny pocket mouse, and in southern Texas especially it is visited by several species of tropical birds.
The legs are stout and spiny, and well adapted for clinging to the hair or feathers of the host animal.
The fur varies exceedingly in character, - in some, like the chinchillas and hares, being fine and soft, while in others it is more or less replaced by spines on the upper surface, as in spiny rats and porcupines; these spines in several genera, as Xerus, Acomys, Platacanthomys, Echinothrix, Loncheres and Echinomys, being flattened.
A distinct sub-family, Lophiomyinae, is represented by the Central African arboreal spiny rats, Lophiomys, of which there are two or three species.
The spiny mice, Acornys (or Acanthomys), of Western Asia, Cyprus and Africa, take their name from the fur being almost entirely replaced by flattened spines, and are further distinguished by the rudimentary coronoid process of the lower jaw.