Chimps, Bonobos and Us
Closest living relative of Homo sapiens? Easy. Chimpanzees, right? It might not be that simple. With the recent sequencing of the bonobo genome, the distinction between the two species is getting fuzzier, as is the question of who’s a closer relative of humans.
Bonobos are a small population of chimpanzee-like apes that live in a tiny pocket of the Congo. They themselves split off of the lineage of chimpanzees less than two million years ago after their population was cut off by the Congo river. Unlike the rather aggressive chimpanzees, who are far more widespread across Africa, bonobos are … well, rather less so.
Bonobos look so much like chimps (the bonobo is on the right up above) that their behavior is one of the few ways to tell them apart. They are known to settle disputes through sex, the gender combination not always important, with the activity even completed while eating. Sex is their cultural currency. Don’t believe me? Watch this.
Chimps do no such thing, to their own recreational detriment.
The sequenced bonobo genome only differs from the chimpanzee genome by 0.4% at the DNA level. That’s within the normal variability of chimp genomes! So are they bonobos or are they chimps? How much of species separation is genetic and how much is behavioral? What, if anything in the small genetic difference leads to those huge behavioral changes? And if they are both so closely related, who is our actual closest relative? This is a debate that will continue.
(via Ars Technica)