The remains of a female Ardipithecus ramidus were found in Ethiopia in 1992. The age of this skull is about 4.4 million years. The skull was found in good condition: most of it, as well as the teeth, were preserved.
Ardi is a more primitive hominid than the widely known australopithecine Lucy. With a height of about 120 cm and a weight of about 50 kg, Ardi was about 15 cm taller than Lucy and nearly twice as heavy.
Ardi lived later than the hypothetical last common ancestor of chimpanzees and humans. The canines of Ardipithecus are smaller than those of chimpanzees and are approximately the same size in males and females. This indicates a reduction in aggression in male-male relationships, the formation of pair bonds, and greater care for offspring.
Based on the shape of the pelvis and limbs, as well as the divergent big toe, it has been established that Ardi was a facultative biped, moving on two legs on the ground and using all four limbs when moving through tree branches. Compared to later hominids, Ardi had a more primitive form of bipedalism and could not walk or run long distances. Her teeth, less specialized than those of modern apes, indicate she was omnivorous.
Ardipithecus were peaceful creatures: males did not have to fight over territory and females, and equality and monogamy were likely the norm in their groups. They lived both in sparse forests and near rivers in even more open woodlands. Without fights and conflicts, they had ample time for their development and for making tools. Moreover, their fairly flexible hands, quite similar to ours, gave them dexterity.
After studying Ardipithecus, a theory emerged that gorillas and chimpanzees are primates from a dead-end branch that happened to survive to the present day.