Thanks for All the Lice Times

We all know that humans and gorillas are closely related (with certain people it’s slightly more evident than with others) but it seems we might have once shared more than the early branches of the primate family tree with our hairy cousins.

Research from the Florida Museum of Natural History revealed that gorillas gave us pubic lice millions of years ago, and left us playing itchy host to them ever since.

The pubic louse parasite, Phthirius pubis, lives in pubic hair and other hairy parts of the body. It sucks blood and can’t survive for long without a host. The only hairy body part that pubic lice avoid is the head, where the bloodsucking-pest niche is occupied by another louse, Pediculus humanus capitis.

The team of researchers, led by David Reed, the museum’s assistant curator of mammals, collected lice from primates in Ugandan wildlife sanctuaries and examined their DNA. Because these parasites evolved alongside their hosts, modern human lice are now a different species from the gorilla lice they diverged from. The primate louse DNA, together with the fossil record, reveal that the two parasite species shared a common ancestor 3.3 million years ago. This suggests that archaic hominids of the time, such as the days best known bipedal Australopithecus, and gorillas lived in very close proximity, which is also news to the scientific community. The results were reported in the March issue of BMC Biology.

Reed and his colleagues came up with three scenarios under which pubic lice could have migrated over from gorillas to colonize the ancestral human crotch, all of which are, in varying degrees, degenerate: One, ancient hominids consumed or otherwise intimately handled gorillas. Two, gorillas and hominids shared beds – but beds only. Or three, gorillas and early hominids got it on (as in sex).

The study also suggests that human head lice (an entirely different species) originated from contact with chimpanzees. Today gorillas suffer from pubic lice, but not head lice, while chimps are the other way around. And lucky us, we humans get to endure both parasites.