Sediments at the site were originally deposited in lakes or rivers, and carbonates found there contain low carbon isotope ratios. This information suggests that, in contrast to the aridity of the current climate, the environment of the Middle Awash during the late Miocene was wet, and the region was occupied by woodland or grassy woodland habitats. The fossilized remains of vertebrates found with the hominids, including the cane rat, further suggest such an environment.[4] The region was also the site of periodic volcanism. This rifting probably created distinct ecological regions inhabited by different species of vertebrate animals.[5]
Important hominid fossils found in the Middle Awash include:[5][6]
