A glance at the evolutionary family tree of humans reveals that the three earliest-known branches ae full of species that appear far more ape-like than the "caveman" stereotype associated with the Homo branch. Some of these strange-looking guys and gals are evolutionary ancestors of humans, but others might be hominids that just co-existed with the ancestors of modern humans, meaning we're related, but we didn't necessarily evolve from them.
Thanks to the efforts of talented sculptors and scientists, we can look at models of these early hominids in museums and online, but the truth is that most of what we know about these species is from a few scattered bone fragments. The fossil record has been filled in tremendously since the first findings in the 1920s, so we're learning an extraordinary amount about the history of human evolution each year. Read on for a brief tour of the major hominids that predated the branch that eventually lead to Homo sapiens (that's you!).
Australopithecus Anamensis: Largest Canine Yet Discovered
Differentiating hominid species between 3.6 and 3.9 million years old is a tricky business. In fact, experts say there are "no discrete and functionally significant anatomical differences" between Australopithecus anamensis and its possible direct ancestor, Australopithicus afarensis. But we do have a few prominent A. anamensis fossils that shed some light on this early human ancestor. A shin bone found in Kenya tells us that this species, like those that preceded it, both walked upright and climbed trees. Other prominent A. anamensis fossils include the largest hominid canine tooth ever found and the earliest Australopithicus femur. The teeth and jaws of A. anamensis suggest a largely plant-based diet.
Australopithecus Afarensis: We Love Lucy
Australopithecus afarensis is perhaps the best-known early human species, with the remains of more than 300 individuals discovered so far, including the famous 3.2-million-year-old "Lucy" skeleton discovered in Ethiopia in the '70s. Lucy and her ilk reached adulthood faster than modern humans, growing more like chimpanzees, with brains about 1/3 the size of a human brain. A. afarensis mainly ate plants, but research suggests they probably ate the occasional lizard, as well, capturing them with their long, strong arms and curved fingers. The species managed to last about 900,000 years, more than quadruple the time that Homo sapiens have been kicking around.
Australopithecus garhi: Making Strides
Very little is known about the 2.5-million-year-old Australopithecus garhi, but what we do know is pretty fascinating. Evidence of a long femur suggests the species made longer strides than other Australopithecus specimens, and their fossils have been associated with some of the oldest known stone tools. Furthermore, animal bones have been found near A. garhi fossils that suggest the species may have used the tools to prepare meat and bone marrow from large animals. Unfortunately, no additional fossils of A. garhi have been discovered since the initial find of a partial skull and other skeletal remains in 1990.
Australopithecus Africanus: The Find That Changed Everything
Before the discovery of Australopithecus africanus in 1924, the world was unaware that the fossils of early humans were buried in Africa. But the scientific community at that time was reluctant to accept "The Man-Ape of South Africa" as a member of the human family tree, so the 3.3- to 2.1-million-year-old A. africanus was considered an ape for decades. Like the other hominids that came before it, this species was bipedal with a mix of human and ape-like features. It ate essentially like a chimpanzee, on a diet of plants, fruit, nuts, seeds, insects, and eggs. A. africanus differs from "Lucy" and the other members of the Australopithecus afarensis species with its larger brain and smaller teeth.