Not all lorises are slow: rapid arboreal locomotion in Loris tardigradus of Southwestern Sri Lanka


  • K.A.I. Nekaris,

    1. Nocturnal Primate Research Group, Department of Anthropology, School of Social Sciences and Law, Oxford Brookes University, Oxford, United Kingdom
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  • N.J. Stevens

    Corresponding author
    1. Department of Biomedical Sciences, College of Osteopathic Medicine, Ohio University, Athens, Ohio
    • Department of Biomedical Sciences, 228 Irvine Hall, Ohio University, Athens, OH 45701
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The unique slow-climbing quadrupedalism of Asian lorises has been the subject of numerous studies; however, qualitative observations of more rapid locomotion have occasionally been reported. Field studies of the red slender loris have revealed the habitual use of unexpectedly high-speed locomotion by the so-called “sloth of the primate world.” Novel video footage permitted the first quantitative kinematic analysis of rapid quadrupedalism in wild lorises. Observations revealed that this previously unexplored behavior is far from infrequent, with 26% of red slender loris locomotor activity being dedicated to high-velocity arboreal quadrupedalism. This locomotor pattern may represent a primitive retention of the rapid, scrambling quadrupedalism that is observed in other strepsirhines, or it may constitute a more recent specialization of this smallest loris taxon. Am. J. Primatol. 69:112–120, 2007. © 2006 Wiley-Liss, Inc.