Ileret

Hominin fossils found near Ileret

In 2012–2013, a Stony Brook University team uncovered hominin fossils at two sites in the Kolom Odiet area near Ileret. The finds represent three individuals: two partial skeletons (KNM-ER 64061 and KNM-ER 64062) and a nearly complete mandible (KNM-ER 64060) missing only the right central incisor. KNM-ER 64060 and KNM-ER 64061 date to 2.02–2.03 million years ago, while KNM-ER 64062 dates to 1.82–1.86 million years ago.

The KNM-ER 64061 skeleton includes most of both humeral shafts, a partial right ulna, right clavicle, and right shoulder blade, with slender but thick-cross-sectioned long bones. KNM-ER 64062 preserves parts of a distal right humerus, scaphoid, and right foot with both primitive and derived features. These individuals most likely represent early Homo: the mandible from Homo habilis and the partial skeletons from Homo erectus.

Homo erectus footprints at Ileret

These trails suggest that early hominins traveled in groups, which researchers interpret as evidence of social behavior. The footprints, found in 1.5-million-year-old sediment, provide information about early foot anatomy and soft-tissue structure that skeletal fossils alone cannot supply. Other Homo erectus fossils of approximately the same age have been found in nearby areas.

Homo erectus compared to other hominins

The Ileret footprints differ from those of apes: the big toe is parallel to the other toes rather than separated in a grasping configuration, the arch is human-like, and the toes are much shorter. Short toes indicate an upright bipedal stance. The footprints also show similarities between Homo erectus and modern humans in body weight, stride, and gait, making H. erectus the first hominin with body proportions comparable to Homo sapiens.

Evidence of bipedalism

Bipedalism is a characteristic of modern humans, with fossil evidence showing hominins walked on two feet as early as 6 to 7 million years ago. Reconstructing gait evolution is difficult due to the scarcity and fragmentary nature of the fossil record. The Ileret footprints provide significant evidence that Homo erectus was bipedal, showing modern human-like weight transfer and supporting earlier interpretations of an arched foot in this species.