Temperature

While many animals exhibit life history strategies that take advantage of patchy resources (both spatial and temporal) by moving between areas where resources are available throughout the year, other species have life histories that enable them to remain dormant during periods of low resource availability. Species that inhabit extreme environments, such as deserts and regions that experience frequent freezing temperatures, have evolved mechanisms to deal with the consequences of seasonal variation in environmental conditions. Nonmigratory species that inhabit areas remaining under snow for periods of the year have to cope with seasonal changes in resources by significantly reducing activity or by lowering their metabolic rate during cold periods. Reduction of metabolic processes saves energy during times when food resources are not available.

Several species cope with seasonal shifts in resources by caching food during times when resources are plentiful in order to survive periods when food is scarce or nonexistent. Many members of the avian family Corvidae harvest seeds throughout the spring, summer, and fall months and cache them in various locations in order to have a food source during the winter and early spring when seeds are not being produced. A classic example of such a species is Clark's nutcracker, which is known to cache over 30 000 seeds at greater than 7000 individual cache sites over a spatial extent of greater than 20 linear km. The Clark's nutcracker will bury seeds beneath soil and plant material throughout the summer and fall. During the winter and early spring, nutcrackers will return to their cache sites by utilizing landmarks and will then unbury their seeds. Clearly, seasonality has played a large role in the selective pressures that have led to the adaptations that facilitate behavior and cognitive abilities of the Clark's nutcracker. Indeed, when a comparative approach is taken, researchers have shown that Corvid species that are less reliant upon stored food for survival are not as diligent at caching food nor are they as good at relocating caches compared to Corvid species that inhabit harsher environments and thus largely rely upon cached seeds for survival.

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