Washington, Bonobos may be more closely linked, anatomically, to human ancestors than chimpanzees, confirms a new study.
Previous research suggested this theory at the molecular level, but this study published in the journal Scientific Reports compared in detail the anatomy of the three species.
"Bonobo muscles have changed least, which means they are the closest we can get to having a 'living' ancestor, " said one of the study authors Bernard Wood, Professor of Human Origins at the George Washington University.
Scientists believe that modern human and common chimpanzee/bonobo lineages split about eight million years ago with the two great ape species splitting about two million years ago.
As common chimpanzees and bonobos evolved after their split, they developed different traits and physical characteristics, even though they remained geographically relatively close, with their main division being the Congo River.
Because of this, researchers have been curious as to what those differences are and how they compare to humans.
By studying the muscles of bonobos (which indicates how they physically function), the team was able to discover that they are more closely related to human anatomy than common chimpanzees.
Earlier studies examined the DNA similarities and differences between bonobos and common chimpanzees, but this was the first study to compare the muscles of the three species.
The researchers led a team that examined seven bonobos from the Antwerp Zoo in Belgium that had died and were being preserved.
Researchers said this was an extremely rare opportunity given bonobos' status as an endangered species.
The scientists noted that having a clear understanding of what makes humans different from our closest living relatives might lead to new breakthroughs or understandings of human health.