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Ardipithecus ramidus

Jaws and teeth

  • much of the dentition is ape-like including relatively large canines and molars
  • tooth enamel thickness is intermediate between that of chimpanzees and Australopithecus
  • canines are less projecting and smaller than those of all other known apes and there is no evidence of honing. The base of the canines in both sexes are similar in size to female chimpanzees and male bonobos, but have shorter crown heights
  • upper canines are shaped like diamonds, rather than the pointed shape seen in African apes, whch is a derived feature shared with Australopithecus afarensis . Lower canines appear to have less derived features.
  • the jaw displayed significant forward projection compared to humans, but less than modern African apes
  • pre-molars have derived features that are more advanced in the human direction
  • canines (non-sharpened and small) and other teeth share features with Orrorin tugenensis


  • skull rests atop the spinal column, indicating this species was bipedal, although it probably walked in a slightly different manner than humans
  • the cranial base is short from front to back, indicating the head balanced on top of the spine
  • the face is small and in a more vertical position than chimpanzees
  • the ridge above the eye socket is unlike that of a chimpanzee



There is no evidence for any specific cultural attributes, but they may have used simple tools similar to those used by modern chimpanzees, including:

  • twigs, sticks and other plant materials that were easily shaped or modified. These may have been used for a variety of simple tasks including obtaining food.
  • unmodified stones, that is stones that were not shaped or altered before being used. These tools may have been used to process hard foods such as nuts.

Environment and diet

Associated animal and plant fossils indicate this species lived a in relatively moist and heavily forested woodland. Fossil species include plants such as fig, palm and hackberry and animals like colobine and baboon-like monkeys, kudu, peafowl, bats, shrews, rodents, doves, eagles, owls and parrots.

The species, with its ape-like feet, probably spent considerable time in the trees looking for food and shelter.

Diet may have included nuts, fruit, leaves, tubers, insects and small mammals. They were probably more omnivorous than chimps (based on the size, shape and enamel of the teeth), and fed both in trees and on the ground. The evidence is inconclusive, but studies suggest the front teeth were regularly used for clamping and pulling, possibly reflecting a diet that included large amounts of leaves. Tooth enamel analysis suggests they ate fruit, nuts and leaves. Carbon-isotope studies of teeth show they ate woodland rather than grassland plants.