TY - JOUR
T1 - Do highly trained monkeys walk like humans? A kinematic study of bipedal locomotion in bipedally trained Japanese macaques
AU - Hirasaki, Eishi
AU - Ogihara, Naomichi
AU - Hamada, Yuzuru
AU - Kumakura, Hiroo
AU - Nakatsukasa, Masato
N1 - Funding Information:
We would like to express our gratitude to the Suo Sarumawashi (Monkey Performance) Association, particularly to the animal trainers for their collaborations. We are also grateful to Prof. Jack T. Stern, Drs. Brigitte Demes and Susan G. Larson of SUNY at Stony Brook, Prof. Russell H. Tuttle of University of Chicago, Dr. Michael M. Günther of the University of Liverpool, Dr. Daniel O. Schmitt of Duke University and Dr. Brian G. Richmond of George Washington University for their invaluable comments. This study was partly supported by JSPS (Japan Society of Promotion of Science) Grant-in-Aids (#12440245 to MN and #14704005 to EH) and 21COE Program (to Division of Biological Science, Kyoto University).
PY - 2004/6
Y1 - 2004/6
N2 - In this study, we examined the kinematics of bipedal walking in macaque monkeys that have been highly trained to stand and walk bipedally, and compared them to the kinematics of bipedal walking in ordinary macaques. The results revealed that the trained macaques walked with longer and less frequent strides than ordinary subjects. In addition, they appear to have used inverted pendulum mechanics during bipedal walking, which resulted in an efficient exchange of potential and kinetic energy. These gait characteristics resulted from the relatively more extended hindlimb joints of the trained macaques. By contrast, the body of the ordinary macaques translated downward during the single-limb stance phase due to more flexed hindlimb joints. This resulted in almost in-phase fluctuations of potential and kinetic energy, which indicated that energy transformation was less efficient in the ordinary macaques. The findings provide two insights into the early stage of the evolution of human bipedalism. First, the finding that training considerably improved bipedal walking a posteriori may explain why the very first bipeds that might not yet have been morphologically adapted to bipedal walking continued to walk bipedally. The evolutionary transition from quadrupedalism to bipedalism might not be as difficult as has been envisioned. In addition, the finding that macaques, which are phylogenetically distant from humans and in which bipedal walking is unlike human walking, could develop humanlike gait characteristics with training, provides strong support for the commonly held but unproven idea that the characteristics of the human gait are advantageous to human bipedalism.
AB - In this study, we examined the kinematics of bipedal walking in macaque monkeys that have been highly trained to stand and walk bipedally, and compared them to the kinematics of bipedal walking in ordinary macaques. The results revealed that the trained macaques walked with longer and less frequent strides than ordinary subjects. In addition, they appear to have used inverted pendulum mechanics during bipedal walking, which resulted in an efficient exchange of potential and kinetic energy. These gait characteristics resulted from the relatively more extended hindlimb joints of the trained macaques. By contrast, the body of the ordinary macaques translated downward during the single-limb stance phase due to more flexed hindlimb joints. This resulted in almost in-phase fluctuations of potential and kinetic energy, which indicated that energy transformation was less efficient in the ordinary macaques. The findings provide two insights into the early stage of the evolution of human bipedalism. First, the finding that training considerably improved bipedal walking a posteriori may explain why the very first bipeds that might not yet have been morphologically adapted to bipedal walking continued to walk bipedally. The evolutionary transition from quadrupedalism to bipedalism might not be as difficult as has been envisioned. In addition, the finding that macaques, which are phylogenetically distant from humans and in which bipedal walking is unlike human walking, could develop humanlike gait characteristics with training, provides strong support for the commonly held but unproven idea that the characteristics of the human gait are advantageous to human bipedalism.
KW - Bipedalism
KW - Energy cost
KW - Hindlimb joints
KW - Inverted pendulum
KW - Macaca fuscata
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U2 - 10.1016/j.jhevol.2004.04.004
DO - 10.1016/j.jhevol.2004.04.004
M3 - Article
C2 - 15183673
AN - SCOPUS:3042841706
VL - 46
SP - 739
EP - 750
JO - Journal of Human Evolution
JF - Journal of Human Evolution
SN - 0047-2484
IS - 6
ER -