Lemur Use of Hands Versus Mouth

Several hypotheses have been offered to explain handedness in primates. In prosimian primates, including lemurs, left-hand orientation has been demonstrated; however, few studies have examined hand vs. mouth orientation. We compared preference for use of hand vs. mouth, single hand over both hands, and right hand vs. left hand in captive ring-tailed lemurs (Lemur catta), black-and-white ruffed lemurs (Varecia variegata), and collared brown lemurs (Eulemur collaris). For a male and female of each species, plus twin female offspring of ring-tailed lemurs, we made 100 observations per individual, recording hand vs. mouth use every 30 seconds as individuals performed enrichment and routine daily activities. Overall, these lemurs tended to be more handed than mouth-oriented, preferred to use a single hand more than both hands, and used their left hand more than their right. Males were more left-handed than females. Analysis of specific activities showed that eating was hand-oriented, while grooming was mouth-oriented. Results are also reported by species. Research on lemur use of hands vs. mouth could provide insight into the evolution of handedness in primates.