1. Life history varies across latitudes, with the ‘pace of life’ being ‘slower’ in tropical regions. Because life history is coupled to energy metabolism via allocation tradeoffs and links between performance capacity and energy use, low metabolic intensity is expected in tropical animals. Low metabolism has been reported for lowland tropical birds, but it is unclear if this is due to ‘slow’ life history or to a warm, stable environment. 2. We measured Basal Metabolic...

We apply an integrative taxonomy approach to delimit species of ground squirrels in the genus Otospermophilus because the diverse evolutionary histories of organisms shape the existence of taxonomic characters. Previous studies of mitochondrial DNA from this group recovered three divergent lineages within Otospermophilus beecheyi separated into northern, central, and southern geographical populations, with Otospermophilus atricapillus nested within the southern lineage of O. beecheyi. To further evaluate species boundaries within this complex, we collected additional genetic...