Body size estimates of "H. rudolfensis" and "H. habilis" typically conclude a small size comparable to australopithecines. These largely depend on the "H. habilis" partial skeleton OH 62 estimated at in height and in weight. "H. rudolfensis" is thought to be bigger than "H. habilis", but it is unclear how big this species was as no bodily elements have been definitively associated with a skull. Based on just the KNM-ER 1470 skull, male "H. rudolfensis" were estimated to have been in height and in weight, and females and . For specimens that might be "H. rudolfensis": the femur KNM-ER 1472 which may also be "H. habilis" or "H. ergaster" was estimated at and , the humerus KNM-ER 1473 and , the partial leg KNM-ER 1481 which may also be "H. ergaster" and , the pelvis KNM-ER 3228 which may also be "H. ergaster" and , and the femur KNM-ER 3728 which may be "H. habilis" or "P. boisei" and . It is generally assumed that pre-"H. ergaster" hominins, including "H. rudolfensis" and "H. habilis", exhibited sexual dimorphism with males markedly bigger than females. However, relative female body mass is unknown in either species. Early hominins, including "H. rudolfensis", are thought to have had thick body hair coverage like modern non-human apes because they appear to have inhabited cooler regions and are thought to have had a less active lifestyle than (presumed hairless) post-"ergaster" species, and so probably required thick body hair to stay warm. The juvenile specimen KNM-ER 62000, a partial face, has the same age landmarks as a 13 to 14 year old modern human, but more likely died at around 8 years of age due to the presumed faster growth rate among early hominins based on dental development rate.