The Behavioral Plasticity of the American Pika

Written by Varner, J., Horns, J.J., et al.

Paper Reviewed: Varner, J., Horns, J.J., Lambert, M.S., Westberg, E., Ruff, J.S., Wolfenberger, K., Beever, E.A. and Dearing, M.D. 2016. Plastic pikas: Behavioural flexibility in low-elevation pikas (Ochotona princeps). Behavioural Processes 125: 63-71. american pika

Behavioral plasticity is the ability of a species to alter its behavior in response to changes in climate. It is an adaptive mechanism that allows species to persist in regions outside their normal climate envelope to which they are generally constrained and therefore represents a means by which they might persist in the face of ongoing climate change. However, behavioral plasticity is an understudied subject and there is much that remains to be learned about this topic.

The latest research team to address this issue was Varner et al. (2016). In a paper published in the journal Behavioural Processes, this team of eight scientists examined American pikas (Ochotona princeps) living in two different habitat ranges in Oregon, USA. One range comprised an elevation, landscape and climate typical of the American pika’s range, while the other was situated within an atypical low-elevation landscape and climate that “appears to be unsuitable [as a pika habitat], based on the species’ previously described thermal niche.” Their purpose for studying pikas at these two different locations was to quantify behavioral differences among them, including differences pertaining to foraging and territorial behaviors. Such observations were made in July of 2011, 2012 and 2013 in which the authors made 5250 pika detections in 417 observer-hours of behavioral data collected across their study location. And what did these data reveal?

Varner et al. report there were “substantial differences” in behavior between pika populations at the two habitats such that “low-elevation pikas do not invest as much time or energy in caching food for winter.” In addition, they were more likely to spend time in forested areas off the open talus landscape around midday than pikas living at higher elevations. This temporal pattern of off-talus behavior, in the words of the authors, “suggests that the forest may serve as a refuge during times of the day that may be most thermally stressful for pikas.” Pikas in the lower elevation and warmer habitat also had smaller home range sizes compared to those at the higher elevation site or in any previously published home range documented for this species.

In consideration of the above, Varner et al. write that their findings “indicate that behavioral plasticity likely allows pikas to accommodate atypical conditions in this low-elevation habitat, and that they may rely on critical habitat factors such as suitable microclimate refugia to behaviorally thermoregulate.” And they thus conclude that “together, these results suggest that behavioral adjustments are one important mechanism by which pikas can persist outside of their previously appreciated dietary and thermal niches. And that is good news, especially for those who are concerned about the potential impacts of global warming on animals.