Shoulder Blades Shed Light On Human Evolution

The complete history of human evolution is a long-standing mystery scientists have yet to fully figure out. The topic typically focuses on the evolutionary trajectory of primates, which over the course of millions of years, has lead to the appearance of anatomically modern humans. As you can imagine, piecing together ancient history involves the combined prowess of many scientific disciplines, and once in a while, a curveball may confuse even the most methodical anthropologists. Other times, a rare “ah-ha!” moment is encountered, which can satisfactorily shed light on the complex timeline of Homo Sapiens.


Take, for example, the recent discovery of fossil shoulder blades belonging to two early human Australopithecus species, which researchers believe provide us with further evidence that humans and apes do indeed share an ape-like ancestor.

But wait. Hasn’t that already been established? Well…yes and no. It’s true that humans are most closely related to the great apes of Africa, as the Washington Post points out. However, after splitting from our closest African ape relative six to seven million years ago, humans seemed to have veered off in a separate direction during the course of human evolution.

Nathan Young, the researcher behind a study published in the Proceedings of the National Academy of Sciences, highlights this fact in a news release. “We have features that clearly link us with African apes, but we also have features that appear more primitive, leading to uncertainty about what our common ancestor looked like.”

Based on this assertion, some scientists have suggested that our common ancestor may have actually been more similar to a monkey.

The new study sets the record straight and “suggests that the simplest explanation, that the ancestor looked a lot like a chimp or gorilla, is the right one, at least in the shoulder.”


At a superficial glance, human shoulder blades are more physically similar to those found in monkeys. However, an analysis of 3-D shoulder blade scans, comparing the fossils of African apes, orangutan, gibbons, monkeys and early and modern humans, revealed that human shoulders do have enough similarities to the shoulder blades of apes to give credence to the ape model.

The trajectory, as the Washington Post points out, wasn’t exact linear, but it is logical. Human shoulders essentially “worked backwards,” moving from the ape’s structure back to an enhanced version of what monkeys have today. The transition parallels the changes characteristic of early human behavior, such as the reduced practice of climbing to the increased use of tools, according to Science World Report.

The results of the study are slowly helping researchers learn more about the enigma that is human evolution.