AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 84:99-101 (1991)

Notes and Comments

A Comment on the Effect of Posture and Locomotion on Energy Expenditure

George Chaplin G.P.O. Box 12766, Connaught Place, Central, Hong Kong

In a recent article in this Journal, Abitbol (1988) compared data on energy ex enditure

quadrupedal and bi edal locomotion. The

evolution is called into question by some serious defects in the methods and experi- mental subjects chosen by the author.

The respiration rate of the do s in Abit-

energy usage. A dog with its forefeet held has its method of breathing altered by the impo- sition of an unnatural posture. It cannot inflate its chest properly because of the un- natural stretching of the thorax and abdo- men. This in turn affects the heat dispersal of the dogs; they of course cannot sweat but rely on panting. Also, in holdin the feet, the

is not controlled. Furthermore, a highly in- bred variety of dogs such as a beagle may not be comparable to natural wild dogs. Finally, the way a dog uses its back muscles (espe- cially a long-backed breed) to sup ort itself is

Jun ers (1988) concluded from a comparison of gi % bons and chimpanzees with man that the back muscles did not have to undergo major chan es in action or function in the evolution of % ipedalism, which involved only “an improvement in the mechanical advan- tages and architecture of these muscles” (p. 201).

in dogs, human adults, and young c R ildren in

value of these data F or students of human

bol’s study was not a good gui % e to their

proportion of weight borne by t a e technician

different from that of a primate. J hapiro and

Abitbol is correct in saying that the chil- dren used in his study were not yet special- ized for bipedalism or quadrupedalism. In- deed, because of their poor motor control, they would tend to be inefficient in all mus- cle activity. Furthermore, the children were not tested at 3.22 kph.

The fixed rate of 3.22 kph used in most of the tests is not a helpful constant. Swing rate in the referred mode of locomotion cor-

would have been more informative. Wa king for an adult biped at that speed is quite comfortable, but it is arduous for a canine quadruped who, proportional to body size, is moving much faster. For an infant, this speed is unattainable.

Abitbol’s study does not take into consider- ation the behavioral milieu of the animals concerned. Wolves (Canis lu us) recline or

about. When they lope along (which is their preferred mode of locomotion)-for instance during hunting-they appear to be tireless. This mode of locomotion seems most likely to have evolved to optimize their hunting abili- ties. For determining evolutionary trends in primates the study of Rodman and McHenry (1980), which was not cited by Abitbol, seems to offer more reliable comparisons and con- clusions.

P rected F or absolute energy consum tion

sleep most of the time an f rarely stand

LITERATURE CITED

Abitbol MM (1988) Effect of posture and locomotion on energy expenditure. Am. J. Phys. Anthropol. 77:191- 200.

Rodman PS, and McHenry HM (1980) Bioenergetics and the origin ofhominid bipedalism. Am. J. Phys. Anthro-

Shapiro LJ, and Jungers WL (1988) Back muscle func- tion during bipedal walking in chimpanzee and gib- bon: Implications for the evolution of human locomo- tion. Am. J . Phys. Anthropol. 77201-212.

pol. 521103-106.

Received December 1,1989; accepted February 26,1990.

@ 1991 WILEY-LISS. INC