Our Ancient Ancestor May Have Been Polygynous, Studies Show
Polygyny is a form of polygamy in which a single male species lives and mates with multiple females, whereas the females in question only mate with a single male. Recent anthropological studies showed that the ancient species Australopithecus afarensis (A. afarensis), in which our ancestor "Lucy" belongs to, observes polygyny.
Polygamy is common in a number of animal species in the wild. However, there is a small fraction of animal populations that observe polygyny. For social animals, this may be an indication of male domination in the species, a phenomenon common to some but not all primate species in the world.
According to a report from Anthropology.net, studies have discovered that the A. afarensis species of hominids, or early humans, may have exhibited dimorphism. This is a condition in which males and females of the same species have distinctly different anatomical and physical characteristics other than the difference in the reproductive system. It has been found that males from this species are significantly larger in size than their female counterparts.
A study from Live Science supported this claim by saying that the reason why this species exhibit dimorphism is possibly because of polygyny in their relationships. Such a relationship between males and females usually lead to extreme competition among males. For better chances of survival and victory, males tend to evolve into much larger sizes.
However, scientists still debate as to whether or not the A. afarensis species have truly exhibited dimorphism as most bone fragments have been collected from the same colony. Some members of the scientific community still believe this is not enough evidence to conclude that they truly are polygynous.
The trends of sexual relationships of many primate species in the world are varied. Though we have all evolved from the same primate, gorillas are among those species that observe polygyny, and chimpanzees are among those that observe polygamy. However, for chimpanzees, their promiscuity is limited to those that are not their kin. Gibbons and humans are among mammals that are strictly monogamous.