Forbidden Archeology: The Hidden History of the Human Race

The knee of Lucy (AL 288), like the original Hadar knee complex (AL 129), had a significant degree of valgus. Johanson, Lovejoy, and others held this to be an indication of humanlike posture and terrestrial bipedal gait. But, as we have seen, the orangutan and spider monkey have similar valgus angles, and they are arboreal.

In our anatomical survey, we have now progessed to the controversial feet of A. afarensis. Even Johanson had a difficult time disguising the manifestly apelike condition of Lucy’s foot. He wrote: “The afarensis phalanges are arched, and proportionally a good deal longer than those in modern feet. They might almost be mistaken for finger bones” (Johanson and Edey 1981, p. 345). Johanson also noted that the A. afarensis foot had “very large muscles whose presence is betrayed by markings along the sides of the phalanges” (Johanson and Edey 1981, p. 345). Such muscles would have been useful in hindlimb grasping.

It is amazing that Johanson could so candidly acknowledge the very apelike morphology of the afarensis foot and yet refuse to draw the obvious conclusion that it was used in arboreal behavior. Instead, Johanson stated: “Although similarly curved phalanges and muscle markings are found in the chimpanzee — reflecting the chimp’s ability to climb trees—Latimer warns that this does not mean that afarensis was a tree climber too” (Johanson and Edey 1981, p. 346 ). Bruce Latimer was one of Johanson’s graduate students and worked with him quite closely in Ethiopia on the Hadar finds, so his impartiality is suspect. He was later employed by Johanson to help with the reconstruction of A. afarensis. It is not unexpected that Latimer would agree with his professor, mentor, and employer that afarensis was a fully terrestrial biped. But researchers operating from more detached and independent standpoints have reached totally different conclusions, which seem to be more in harmony with the evidence.

In studying the most complete A. afarensis foot, AL 333-115 from the First Family group, Stern and Susman (1983, p. 306) found that the proximal phalanges (the bones at the base of each toe) had a “strikingly pongid morphology.” This was true in terms of both their length and curvature.

Susman, reporting the conclusions of an investigation into the curvature of proximal phalanges in a variety of apes, stated that the chimpanzee and bonobo, or pygmy chimpanzee, had “the most curved toe bones of any ape plotted” (Susman et al. 1984, p. 125). And the proximal phalanges of AL 333-115 were “more curved than in the average bonobo” (Susman et al. 1984, p. 125). In other words, A. afarensis was apparently more apelike, in this respect, than any of the living apes. Human proximal phalanges are nearly straight.

Like the proximal phalanges, the other toes bones of A. afarensis also displayed apelike features. Altogether, the long, curved toes of A. afarensis, accompanied by powerful grasping muscles, would have been well suited for arboreal behavior.

Susman concluded: “at the very least the small individuals should have been able to grab with their toes as well as 2-year old children grab with their fingers. The large Hadar individuals probably could use their toes for simple grasping as effectively as considerably older human children use their fingers. . . . the strength of the grip may have well exceeded the strength of hand grip in young humans” (Susman et al. 1984, p. 124). Lending support to this conclusion, the A. afarensis fibula (the smaller of the two bones of the lower leg) was quite robust, indicating the presence of powerful muscles for flexing the foot (Susman et al. 1984, p. 124).

According to Johanson, Latimer, who was opposed to arboreality, concluded that “afarensis was an exceptionally strong walker, and that its elongated toes may have been of service to it when moving over rough stony ground, or in mud, where some slight gripping ability would have been useful” (Johanson and Edey 1981, pp. 345–346).

Stern and Susman (1983, p. 308) found this notion “untenable,” observing that “curved toes are found only in species that engage in arboreal behavior.”

Stern and Susman (1983, p. 308) further stated: “There is no evidence that any extant primate has long, curved, heavily muscled hands and feet for any purpose other than to meet the demands of full or part-time arboreal life.”

Another apelike feature of the A. afarensis foot can be found in the hallux, or big toe. Studies by Susman showed that the A. afarensis hallux could be extended sideways, like the human thumb (Susman et al. 1984, pp. 137–138).