Abstract
The existence of differences in pelvic morphology between Plio-Pleistocene hominids and modern humans is well documented (for a recent review see McHenry and Temerin, 1979). Pelvic remodeling during the evolution of the genus Homo has elicited two different interpretations: (1) it has been viewed as a reflection of increased efficiency in bipedalism (McHenry, 1975a; Zihlman, 1978), and (2) it has been interpreted in terms of rapid encephalization that would have generated selection pressure to increase birth canal dimensions (Lovejoy et al., 1973; Lovejoy, 1974, 1975, 1978). When the second hypothesis is scrutinized, the fossil evidence unambiguously indicates that the increase in brain size during human evolution was extraordinary both in magnitude and in rate (Pilbeam and Gould, 1974; Passingham, 1975; Sacher, 1975). This picture of encephalization from H. habilis to H. erectus to H. sapiens is based on estimated cranial capacities of a static series of adults. Obstetrical constraints and thus selection pressures on the pelvis are not, however, dependent on adult cranial dimensions but on those of the fetal cranium at term relative to birth canal dimensions. Moreover, evidence of differences between primate species in the growth rate of the brain and/or in the length of development during ontogeny (Schultz, 1941, 1956; Sacher and Staffeldt, 1974; Passingham, 1975) suggests that encephalization of adults cannot be expected to be proportionate to that of the neonate or to that of individuals at any particular developmental stage.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
Similar content being viewed by others
References
Bauchot, R., and Stephan, H., 1969, Encéphalisation et niveau évolutif chez les simiens. Mammalia, 30:235–275.
Biegert, J., 1957, Der Formwandel des Primatenschädels und seine Beziehungen zur ontogenetischen Entwicklung und den phylogenetischen Spezialisationen der Kopforgane. Morph. Jb., 98:77–199.
Biegert, J., 1963. The evaluation of characteristics of the skull, hands, and feet for primate taxonomy. In, Classification and Human Evolution, S. L. Washburn, ed., Aldine, Chicago, pp. 116–145.
Biegert, J., and Maurer, R., 1972, Rumpfskelettlänge, Allometrien und Körperproportionen bei catarrhinen Primaten. Folia Primatol., 17:142–156.
Bowden, D., Winter, P., and Ploog, D., 1967, Pregnancy and delivery behavior in the squirrel monkey (Saimiri sciureus) and other primates. Folia Primatol., 5:1–42.
Brandt, E.M., and Mitchell, G., 1971. Parturition in primates: behavior related to birth. In, Primate Behavior, Developments in Field and Laboratory Research, vol. 2, L.A. Rosenblum, ed., Academic Press, New York, pp. 177–223.
Christen, A., 1974, Fortpflanzungsbiologie und Verhalten bei Cebuella pygmaea und Tamarin tamarin (Primates, Platyrrhina, Callithricidae). Z. Tierpsychol., Suppl., 14:1–80.
Doyle, G.A., 1979. Development of behavior in prosimians with special reference to the lesser bushbaby, Galago senegalensis moholi. In, The Study of Prosimian Behavior, G.A. Doyle and R.D. Martin, eds., Academic Press, London, pp. 157–206.
Gillman, J. and Gilbert, C., 1946, The reproductive cycle of the chacma baboon (Papio ursinus) with special reference to the problem of menstrual irregularities as assessed by the behavior of the sex skin. S. Afr. J. Med. Sci. Biol., Suppl., 11:1–54.
Goss, C.M., Popejoy, L.T.II, Fusiler, J.L., and Smith, T.M., 1968. Observations on the relationship between embryological development, time of conception, and gestation. In, The Squirrel Monkey, L.A. Rosenblum and R.W. Cooper, eds., Academic Press, New York, pp. 171–191.
Gould, S.J., 1975, Allometry in primates, with emphasis on scaling and the evolution of the brain. Contrib. Primatol., 5:244–292.
Gould, S.J., 1977. Ontogeny and Phylogeny, Belknap Press, Cambridge, Mass.
Hemmer, H., 1971. Beitrag zur Erfassung der progressiven Cephalisation bei Primaten. In, Proc. 3rd Int. Congr. Primatol, vol. 1, J. Biegert and W. Leutenegger, eds., Karger, Basel, pp. 99–107.
Hopf, A., 1967, Notes on pregnancy, delivery and infant survival in captive squirrel monkeys. Primates, 8:323–332.
Huggett, A. St G., and Widdas, W.F., 1951, The relationship between mammalian foetal weight and conception age. J. Physiol. Lond., 114:306–317.
Leutenegger, W., 1970a, Das Becken der rezenten Primaten. Morph. Jb., 115:1–101.
Leutenegger, W., 1970b, Beziehungen zwischen der Neugeborenengrösse und dem Sexualdimorphismus am Becken bei simischen Primaten. Folia Primatol., 12:224–235.
Leutenegger, W., 1972, Newborn size and pelvic dimensions in Australopithecus. Nature, 240:568–569.
Leutenegger, W., 1973, Maternal-fetal weight relationships in primates. Folia Primatol., 20:280–293.
Leutenegger, W., 1974, Functional aspects of pelvic morphology in simian primates. J. Hum. Evol., 3:207–222.
Leutenegger, W., 1976, Allometry of neonatal size in eutherian mammals. Nature, 263:229–230.
Leutenegger, W., 1977, A functional interpretation of the sacrum of Australopithecus africanus. S. Afr. J. Sci., 73:308–310.
Leutenegger, W., 1979, Evolution of litter size in primates. Am. Nat., 114:525–531.
Lovejoy, C.O., 1974, The gait of australopithecines. Yrbk. Phys. Anthrop., 17:147–161.
Lovejoy, C.O., 1975. Biomechanical perspectives on the lower limb of early hominids. In, Primate Functional Morphology and Evolution, R.H. Tuttle, ed., Mouton, The Hague, pp. 291–326.
Lovejoy, C.O., 1978. A biomechanical review of the locomotor diversity of early hominids, in: Early Hominids of Africa, C.J. Jolly, ed., Duckworth, London, pp. 403–429.
Lovejoy, C.O., 1979. A reconstruction of the pelvis of AL-288 (Hadar Formation, Ethiopia). Paper presented at 48th Annual Meeting of the Am. Ass. Phys. Anthrop., San Francisco, Calif.
Lovejoy, C.O., Heiple, K.G., and Burstein, A.H., 1973, The gait of Australopithecus. Am. J. Phys. Anthrop., 38:757–780.
McHenry, H.M., 1975a, Biomechanical interpretation of the early hominid hip. J. Hum. Evol., 4:343–356.
McHenry, H.M., 1975b, Fossils and the mosaic nature of human evolution. Science, 190:425–431.
McHenry, H.M., 1975c, Fossil hominid body weight and brain size. Nature, 254:686–688.
McHenry, H.M. and L.A. Temerin, 1979, The evolution of hominid bipedalism; evidence from the fossil record. Yrbk. Phys. Anthrop., 22:105–131.
Olivier, A. and H. Pineau, 1958, Croissance prénatale comparée du macaque et de l’homme. C. R. Acad. Sci. Paris, 246:1292–1293.
Passingham, R.E., 1975, Changes in the size and organisation of the brain in man and his ancestors. Brain Behav. Evol., 11:73–90.
Phillips, I.R., 1976, The reproductive potential of the common cotton-eared marmoset (Callithrix jacchus) in captivity. J. Med. Primatol., 5:49–55.
Pilbeam, D. and Gould, S.J., 1974, Size and scaling in human evolution. Science, 186:892–901.
Portmann, A., 1941, Die Tragzeiten der Primaten und die Dauer der Schwangerschaft beim Menschen: ein Problem der vergleichenden Biologie. Rev. Suisse Zool., 48:511–518.
Portmann, A., 1945, Die Ontogenese des Menschen als Problem der Evolutionsforschung. Verh. Schweiz. Naturforsch. Ges., 125:44–53.
Sacher, G.A., 1975. Maturation and longevity in relation to cranial capacity in hominid evolution. In, Primate Functional Morphology and Evolution, R.H. Tuttle, ed., Mouton, The Hague, pp. 417–441.
Sacher, G.A., and Staffeidt, E.F., 1974, Relation of gestation time to brain weight for placental mammals: implications for the theory of vertebrate growth. Am. Nat., 108:593–615.
Schultz, A.H., 1941, The relative size of the cranial capacity in primates. Am. J. Phys. Anthrop., 28:273–287.
Schultz, A.H, 1949, Sex differences in the pelves of primates. Am. J. Phys. Anthrop., 7:401–424.
Schultz, A.H., 1956. Postembryonic age changes, in: Primatologia, vol. 1, H. Hofer, A.H. Schultz and D. Starck, eds., Karger, Basel, pp. 887–964.
Schultz, A.H., 1969. The Life of Primates, Universe Books, New York.
Zihlman, A., 1978. Interpretations of early hominid locomotion. In, Early Hominids in Africa, C.J. Jolly, ed., Duckworth, London, pp. 361–377.
Zuckerman, S., Ashton, E.H., Flinn, R.M., Oxnard, C.E., and Spence, T.F., 1973, Some locomotor features of the pelvic girdle in primates. Symp. Zool. Soc. Lond., 33:71–165.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 1982 Plenum Press, New York
About this chapter
Cite this chapter
Leutenegger, W. (1982). Encephalization and Obstetrics in Primates with Particular Reference to Human Evolution. In: Armstrong, E., Falk, D. (eds) Primate Brain Evolution. Springer, Boston, MA. https://doi.org/10.1007/978-1-4684-4148-2_7
Download citation
DOI: https://doi.org/10.1007/978-1-4684-4148-2_7
Publisher Name: Springer, Boston, MA
Print ISBN: 978-1-4684-4150-5
Online ISBN: 978-1-4684-4148-2
eBook Packages: Springer Book Archive