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How large was the brain of Australopithecus africanus?

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Side view illustration of Australopithecus afarensis, an early human ancestor, shown walking upright with a hairy body and ape-like facial features. A scale beside the figure marks 12 inches and 40 centimeters. — Australopithecus Artist's rendering of *Australopithecus afarensis*, which lived from 3.8 to 2.9 million years ago.

The brain size of Australopithecus africanus was relatively small, with an average volume of approximately 448 cc (27.3 cubic inches) and an estimated average mass of 450 grams (0.99 pound).12

This capacity is comparable to that of modern chimpanzees and is roughly one-third the size of the average human brain, which is approximately 1,350 cc (82.4 cubic inches). While early researchers initially doubted the status of A. africanus as a human ancestor due to this small brain size, the fossil record has since demonstrated that human evolution was characterized by the early adoption of bipedalism while brain size remained essentially apelike for a significant period.134

It is important to note that cranial capacity provides only a rough estimate of brain size, and researchers caution against directly correlating these measurements with cognitive capabilities or intelligence.25