The australopithecines and Homo habilis have been publicized for years as examples of evolutionary transitional forms that launched our own human lineage. Dogmatic evolutionists have rationalized these claims on the basis of brain expansion, encephalization quotients, and bipedalism. However, any evolutionary justification for brain expansion in these extinct creatures must rest in a precise model for the determination of body mass. To insure an accurate body mass model, one must take into account whether the animal is quadruped, facultative biped, or obligatory biped. Past body mass estimates for the australopithecines and Homo habilis were based on assumptions about their bipedalism that have proven to be erroneous. When a body mass model is used accounting for the facultative bipedalism of the australopithecines and Homo habilis, the data shows that they are not highly encephalized, and hence nothing more than a microevolutionary adaptation of the pan-troglodytes.