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Locomotor Ability and Wariness in Yellow-Bellied Marmots

Authors


Daniel T. Blumstein, Department of Ecology and Evolutionary Biology, 621 Young Drive South, University of California, Los Angeles, CA 90095-1606, USA. E-mail: marmots@ucla.edu

Abstract

Animals employ a variety of behaviors to reduce or manage predation risk. Often, these are studied in isolation, but selection may act on packages of behavior that are referred to as behavioral syndromes. We focused on yellow-bellied marmots (Marmota flaviventris) and examined three commonly studied antipredator behaviors. We fitted general linear models to explain variation in maximum running speed, time allocated to vigilance and foraging during bouts of foraging, and flight initiation distance (FID). Marmot maximum running speed was influenced by the substrate run across; marmots ran fastest across dirt or low vegetation and slowest across stones or talus. Incline and several other variables shown to affect running speed in other marmot species failed to explain significant variation in yellow-bellied marmots. From these results we expected marmots to be sensitive to substrate while foraging, but insensitive to incline. However, time allocated to foraging was affected by incline but not by substrate. In bouts of foraging observed in different habitats, and on different inclines, more time was allocated to foraging and less to vigilance on steep slopes and less on level ground. Substrate influenced FID. Marmots in tall vegetation were less tolerant of an approaching person than were those in shorter vegetation. Finally, we found significant correlations between the residuals from the maximum running speed model and the residuals from the time allocated to vigilance and foraging models. We found a tendency for marmots that ran slower than predicted to be less vigilant while foraging. We also found that relatively slow marmots engaged in more active foraging and less vigilance during foraging bouts. This finding suggests a ‘locomotor ability-wariness while foraging’ syndrome. It also suggests that vulnerable individuals minimize their exposure while foraging.

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