The first known human lived in Ethiopia 2.8 million years ago, according to two remarkable new studies that also reveal the conditions under which the earliest humans evolved.
Prior to this research, which is published in the journal Science, the earliest known member of our genus was dated to around 2.3-2.4 million years ago, so the new remains push back the history of humanity by approximately 400,000 years.
“Prior to 3 million years, humans were relatively ape-like and partially arboreal, partially bipedal,” Brian Villmoare, who led the research on the fossil remains, told Discovery News. “They lived in the forest, had small brains, and did not eat meat or use tools.”
“After 2 million years,” he continued, “humans have large brains, stone tools, and eat meat, so this transitional period is very important in terms of human evolution.”
The 2.8-million-year old remains consist of a fossil lower jaw and teeth. They were unearthed at the Ledi-Geraru research area at Afar Regional State, Ethiopia.
Villmoare, a researcher at the University of Nevada Las Vegas, and his colleagues do not name the individual’s species, but it likely is the common ancestor of at least two separate human lineages that split at around 2.3 million years ago, with one remaining in Ethiopia and the other going to Tanzania.
Since only a jaw bone with teeth are all that’s believed to be left of the first known human, the scientists cannot say much about what this individual’s body looked like.
“But,” Villmoare quickly added, “there does appear to have been a general reduction in skeletal and dental elements in this jaw, which is consistent with the transition to the Homo adaptive pattern.”
As humans likely evolved from the more ape-like Australopithecus, represented by the famous “Lucy” remains, we started to lose features evolved for a past life in trees and to gain characteristics associated more with modern humans, such as shorter arms.
In a separate study led by Erin DiMaggio of Pennsylvania State University, the ecosystem where the first known human was found is described. Clearly, this individual had a lot of company.
“We found a large number of fossils of grazing animals, similar to modern wildebeests and zebras, which show that early Homo lived in an area of grasslands, similar to the modern Serengeti Plains in Tanzania, except that this habitat had rivers and lakes as we have fish, hippos, and crocodiles, as well as antelope that lived near grasses inundated with water,” co-author Kaye Reed of the Institute of Human Origins and School of Human Evolution and Social Change, told Discovery News. “There were very few trees, however, except possibly a few near the water sources.”
Reed added that she and her colleagues also recovered saber-toothed cats and hyenas, two types of warthogs and a very large baboon that is related to the modern gelada baboon seen today in the Ethiopian highlands.