A new member of the human family tree named Homo naledi has recently been discovered in Rising Star Cave, 30 kilometers northwest of Johannesburg, South Africa. The fossils that were found give unique insight into the development of the human species, while also bringing up many new questions.
Excavating the fossils was a dangerous and intimidating task. It involved traveling through 90 meters of small chambers and tight spaces, and squeezing through a narrow 7.5 inch chute. Lee Berger, a research professor and National Geographic Explorer-in-Residence, directed the expedition. Skinny scientists were needed to crawl through the small spaces, and by reaching out to the public through social media, Lee put together a team of six female researchers to complete the job. While underground, the women collected fossil pieces while communicating locations with a team above ground. The discovery included 15 hominid individuals that were pieced together from over 1,500 collected fossil fragments. These individuals ranged from infants to adults, as well as elderly Homo naledi.
The “Homo” evolutionary group represents the closest relatives of modern day humans. Through studying the fossils, scientists have found that Homo naledi possessed a combination of human and primal characteristics; they walked upright, and had small hands and feet that resembled those of modern day humans. Conversely, their brain and skull size was smaller than that of Homo sapiens. As adults, they were approximately 5 feet tall and weighed about 100 pounds.
Many questions have arisen as to how old the bone fragments are, how they were brought to such an isolated area in the cave, and how they stayed well preserved over the years. Homo naledi most likely originated at the beginning of the Homo genus, 2.5-2.8 million years ago. Scientists do not yet know exactly how old the fossils are because of their unusual environment in the cave, but they estimate that the fossils found are about 2 million years old. Possible scenarios as to the location of the fossils include that Homo naledi buried their dead in the cave, or that the 15 individuals were accidentally trapped and died inside the cave.
Although scientists do not know the full story of Homo naledi, they are intrigued by the recent discoveries and excited to make more discoveries about human evolution. There is also hope that there are more fossils to find in the Rising Star Cave. In the October Issue of National Geographic, Lee Berger wrote: “The chamber has not given up all its secrets. There are potentially hundreds if not thousands of remains of Homo naledi still down there.”
(Sources: NY Times, CNN, NBC News)