Duration Of Movement As A Lizard Foraging Movement Variable
Studies of lizard foraging modes and their correlates have led to major advances in our understanding of the evolution of lizard taxonomic, morphological, physiological, ecological and behavioral diversity. Although two basic foraging modes, ambush and active foraging, have been recognized, variability in foraging movements among species has led to controversies about their existence and the complexity and continuity of foraging behaviors. The variables central to the controversies are number of movements per minute and percent time moving. A third variable, the average duration per bout of movement, has been neglected. For 80 species I show that average duration, like the other variables, is continuous, unimodal, and lognormally distributed. Average duration is highly correlated with percent time moving, but only weakly with number of movements per minute. In discriminant function analysis and cluster analyses, average duration performed slightly worse at separating species by mode than percent time moving as a single variable and in combination with movements per minute. Because it is so highly correlated with percent time moving, average duration cannot be used as a third axis of a multivariable foraging space, but a variable indicating the variability of movement duration might provide new insights. Species for which modes were misclassified had percent time moving close to 10%. Average duration data support earlier reports that some gekkonids have unusually long-lasting movements for ambush foragers, yet remain immobile for long intervals between movements.
lizards, foraging, duration
William E. Cooper Jr. (2005).
Duration Of Movement As A Lizard Foraging Movement Variable. Herpetologica.61 (4), 363-372.