The human evolutionary tree has many branches. One of these branches includes all species in the Paranthropus genus, including Paranthropus boisei who lived 2.3 to 1.2 million years ago in eastern Africa. Fossils of Paranthropus boisei are characterized by a skull that is adapted for heavy chewing with a large sagittal crest on the top of the braincase. There is evidence of large chewing muscles and massive teeth: 4 times the size of our own teeth! They also had flaring cheekbones with a wide and dish-shaped face. Although their anatomy suggests they would survive on tough leaves, stems, and roots, patterns of wear on their teeth indicate that their diet was mostly composed of fruit and less tough plant material. Their fossils have been found alongside other early human species such as Homo erectus. This coexistence indicates that the pattern of human evolution was like a tree with many branches, rather than a single lineage of one species evolving into another.