Alternative foraging tactics of juvenile Gopher tortoises examined using correlated random walk models

17september2008
Source: Herpetologica, vol 63, issue 4, 2007
Most animals forage under the risk of predation. An animal may balance the benefits gained from obtaining adequate nutritious forage with the risk of falling prey to a predator by employing alternative, adaptive foraging tactics.
We examined the foraging tactics employed by a central place forager, Gopherus polyphemus, as it foraged away from a refuge. We directly observed foraging paths of juvenile G. polyphemus and analyzed them using correlated random walk models. We also compared the sinuosity of foraging paths to the sinuosity of an optimal central place forager. Observed net squared displacement was greater than expected for outbound foraging paths and inbound return paths, but these paths could not be distinguished statistically from a correlated random walk. Sinuosity was less than expected for an optimal central place forager. Juvenile tortoises direct movement away from their burrows while foraging. Juveniles may give up the security of remaining near their burrows to forage until satiation.


Title: Alternative foraging tactics of juvenile Gopher tortoises (Gopherus polyphemus) examined using correlated random walk models

Authors: Brian J. Halstead, Earl D. McCoy, Terri A. Stilson, and Henry R. Mushinsky