Abstract # 84:

Scheduled for Thursday, June 18, 2015 06:00 PM-08:00 PM: (Cascade AJBCD) Poster Presentation


Q. Liu and M. Joel
State University of New York at Oswego, Department of Psychology, Oswego, NY 13126, USA
     We aim to examine and compare the nut-cracking actions of a disabled wild capuchin monkey (Sapajus libidinosus) in Brazil before, immediately after, and up to three years following the disabling incident. We recorded 53 episodes (range 8-16 per year) for the subject over five consecutive field seasons and 42 episodes (range 5-10) for another adult male as a comparison. We coded actions and outcome in nut-cracking. In a subset of episodes (N=15), we conducted biomechanical analysis and examined movement patterns and temporal variations in the highest strikes per episode. Immediately after injury, the disabled individual’s control of stone and balance of body drastically decreased. He also used his tail as support after injury. Efficiency and body weight was lowest one year after the injury but other behavioral measures of effective nut-cracking were starting to improve at one year and returned to pre-injury levels two to three years after the injury. Lifting height and velocity was significantly lower (ANOVA, alpha=0.05) immediately following injury but was starting to approach pre-injury levels one year after the incident. The subject also maintained the same kinematic strategies and his individual lifting/striking pattern even immediately after injury. Both behavioral and biomechanics data combine to reveal how a severe disability can be effectively accommodated by a highly skilled individual during strenuous percussive tool use. This case highlights behavioral adaptability in wild primates.