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The orang-utan of Hoa` Binh (Vietnam): body weight and locomotor hypothesis. The discovery of the first complete skeleton of an adult orang-utan (Pongo pygmaeus), probably a female, in the Hoa` Binh province, Vietnam, brings original data about the evolution of these primates. We have predicted the body weight of this orang-utan by using two parameters : dental (crown area of cheek teeth) and skeletal (lengths of femur, radius and tibia). The dental dimensions give plausible predicted estimates of body weights that range between 70.9–112.4 kg for M1 (with a mean of 89.3 kg) and 67.9–98.1 kg for M1 (with a mean of 81.6 kg). From the observations of Sugardjito and van Hoof [21] on modern orang-utans, heavy body weights have some influence both on the employment of certain types of locomotion and on travelling heights. To cite this article : A.-M. Bacon, V.T. Long, C. R. Palevol 2 (2003). [Copyright &y& Elsevier]

The techniques involved in the measurement of the electrophoretic mobilities of human proteins have been applied for similar protein electrophoretic mobility measurements in various species of anthropoïd apes. A study of the electrophoretic polymorphism in the chimpanzee shows that this species has a similar variability to that of man, although the average individual heterozygosity level is lower. For a certain number of erythrocyte protein loci, the electrophoretic mobilities in man, chimpanzee, and gorilla are about the same. The two types of chimpanzee are distinguished by their distinct allelic forms at the level of only one locus, the transferrin locus. The various sub-species of the common chimpanzee, gorilla, and orang-utan differ at the discriminative post-albumin and transferrin locus, not only in their allelic forms but also in the degree of heterozygoty. A study of such differences enables the proposal of a hypothesis about the relationships between these diverse races. Amongst these, the two sub-species of orang-utan are distinguishable by other diagnostic markers. It would seem that in a study of specific differentiation applicable to that of the human species, the different types of baboons constitute a better model than that of the various anthropoïd apes.