Scientists believe that the private life of ancient people bore a striking resemblance to that of modern gorillas. One dominant male with a female harem was quite typical of them.
The research of 35 Paranthropus robustus hominid fossils, who lived on Earth about two million years ago, showed considerable differences between males and females. The research shed some light on peculiarities of their mating behavior. The growth of male Paranthropus boisei continued even at a mature age which is much longer in comparison with modern humans. British and Italian scientists found out that they were much bigger than females in that period.
As a rule, such disproportion in dimensions – sexual dimorphism – is connected with the marriage arrangements, when one dominant male controls many females, and inferior smaller ones do not look certain to procreate. The sex life of gorillas is organized similarly. Male gorillas grow throughout their lives to become mature silverbacks in their groups, to dominate and command their harems.
A new research published in Science journal makes us believe that ancient hominid Paranthropus boisei had much in common with gorillas. “When we examined fossils from 1.5 to 2 million years ago we found that in one of our close relatives the males continued to grow well into adulthood, just as they do in gorillas,”- said Dr Charles Lockwood from University College London, the lead author of the study.
“This resulted in a much bigger size difference between males and females than we see today. It is common knowledge that boys mature later than girls, but in humans the difference is actually much less marked than in some other primates. Male gorillas continue to grow long after their wisdom teeth have come through, and they do not reach what is referred to as dominant ‘silverback’ status until many years after the females have already started to have offspring. Our research makes us think that in this fossil species, one older male was probably dominant in a troop of females. This situation was risky for the males and they suffered high rates of predation as a result of both their social structure and pattern of growth,” he said.
The fossil comes from the palaeontological sites of Swartkrans, Drimolen and Kromdraai near Johannesburg. Many of them are supposed to belong to predators. There are considerably more males than females among fossil hominids, and it, probably, reflects their way of life.
To all appearances, young males unable to dominate lived alone or in small groups, which made them more vulnerable, Dr Lockwood says.
“Basically, males had a high-risk lifestyle in the species. They most likely left their birth groups at about the time they reached maturity, and it was a long time before they were mature enough to attract females and establish a new group. Some of them were killed by predators before they got the chance.”
Paranthropus robustus is not immediate ancestor of modern people; it belongs to a separate branch of genealogical tree, which does not exist now. Paranthropus robustus was orthograde and walked on two legs. An adult was about 1,3 -1,4 m.
Translated by Ksenia Sedyakina