Early humans 'more promiscuous'

A team of scientists studied the fossilised finger bones of extinct apes and hominins, extinct members of human lineage, to learn more about their hormonal activity.

The novel approach to understanding how our ancestors behaved was conducted by a team from Liverpool, Oxford, Southampton and Calgary Universities, and is published in the latest issue of Proceedings of the Royal Society.

The finger ratios from fossilised skeletal remains of early apes and hominins can be used as indicators of the levels of exposure species had to prenatal androgens, a group of hormones that is important in the development of masculine characteristics such as aggression and promiscuity, the study said.

High levels of the hormones increase the length of the fourth finger in comparison to the second finger, resulting in a low index to ring finger ratio.

The team found that the fossil finger ratios of Neanderthals, and early members of the human species, were lower than most living humans, which suggests that they had been exposed to high levels of prenatal androgens. This indicates that early humans were likely to be more competitive and promiscuous than people today.

Emma Nelson, from Liverpool University's School of Archaeology, said: "It is believed that prenatal androgens affect the genes responsible for the development of fingers, toes and the reproductive system."