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Climate change has led animal species to shift their ranges to greater elevations, latitudes, and depths, tracking their preferred abiotic niche. However, there is extensive variation in these shifts, and some species have not shifted their ranges at all. Some of this variation arises because species’ distributions not only align with the abiotic environment but are also shaped by biotic factors and movement. Through facilitating rapid adaptive responses to climate-mediated changes to abiotic, biotic, and movement factors, behavioral plasticity allows populations to survive environmental change by persisting in place, while also enabling successful establishment in novel habitats when shifting in space. 

How animals behave in novel situations may significantly affect multiple aspects of their biology, including how they respond to environmental change. Two aspects of behaviour that are often used to assess interactions with new environments are exploration and boldness. Within species, variation in these responses to novelty is thought to reflect differences in individual behavioural phenotypes (e.g. behavioural syndromes). Between species, these responses may be influenced by the degree of ecological specialization, with members of more specialized taxa typically expected to display a reduced tendency to interact with novel habitats. To test the prediction that more ecologically specialized species are more neophobic, we used open-field assays to compare exploratory behaviour and boldness among free-living members of two partially sympatric species of chipmunks from the Sierra Nevada Mountains of California, U.S.A.: the lodgepole chipmunk, Tamias speciosus, a habitat generalist, and the alpine chipmunk, Tamias alpinus, a habitat specialist. Our analyses indicate that while behavioural measures of boldness did not differ between these species, individual T. speciosus were on average more exploratory than individual T. alpinus. Although the number of individuals tested per species was limited, these findings have important implications for understanding reported interspecific differences in elevational range shifts in response to changing environmental conditions in the Sierra Nevada. More generally, our analyses underscore the potential importance of behavioural responses to novelty in shaping species level patterns of response to environmental change. 

Abstract Escape theory has been exceptionally successful in conceptualizing and accurately predicting effects of numerous factors that affect predation risk and explaining variation in flight initiation distance (FID; predator–prey distance when escape begins). Less explored is the relative orientation of an approaching predator, prey, and its eventual refuge. The relationship between an approaching threat and its refuge can be expressed as an angle we call the “interpath angle” or “Φ,” which describes the angle between the paths of predator and prey to the prey’s refuge and thus expresses the degree to which prey must run toward an approaching predator. In general, we might expect that prey would escape at greater distances if they must flee toward a predator to reach its burrow. The “race for life” model makes formal predictions about how Φ should affect FID. We evaluated the model by studying escape decisions in yellow-bellied marmots Marmota flaviventer, a species which flees to burrows. We found support for some of the model’s predictions, yet the relationship between Φ and FID was less clear. Marmots may not assess Φ in a continuous fashion; but we found that binning angle into 4 45° bins explained a similar amount of variation as models that analyzed angle continuously. Future studies of Φ, especially those that focus on how different species perceive relative orientation, will likely enhance our understanding of its importance in flight decisions.