|Many hystricognaths live in South, Central and North America,
e.g. capybara, cavy or guinea-pig, coypu and the New World Porcupines; they generally have large
heads, plump bodies, slender legs and short tails. The sub-order also includes
the Old World porcupines belonging to the family Hystricidae, which gives the
group their subordinal name, and such diverse creatures as
chinchillas, gerbils and the African Mole Rat.
Many are large rodents and used for food - capybara and guinea-pigs in South America; cane-rats and porcupines in Africa.
Skulls and dentition
|Hystricognath skulls are rather angular with very strongly
developed incisors. The surfaces of the cheek teeth show enormous variation in pattern
and complexity among different species.
The gnawing action is provided by the deep masseter muscle which extends forward through an opening in the zygomatic arch and attaches to the muzzle. The other end attaches to a characteristic outward projecting flange of the lower jaw. The lateral muscle is only used to close the jaw.