Specialized spatial cognition is associated with reduced cognitive senescence in a food-caching bird

Abstract

Senescence, the gradual reduction and loss of function as organisms age, is a widespread process that is especially pronounced in cognitive abilities. Senescence appears to have a genetic basis and can be affected by evolutionary processes. If cognitive senescence is shaped by natural selection, it may be linked with selection on cognitive abilities needed for survival and reproduction, such that species where fitness is directly related to cognitive abilities should evolve delayed cognitive senescence likely resulting in higher lifetime fitness. We used wild food-caching mountain chickadees, which rely on specialized spatial cognition to recover thousands of food caches annually, to test for cognitive senescence in spatial learning and memory and reversal spatial learning and memory abilities. We detected no signs of age-related senescence in spatial cognitive performance on either task in birds ranging from 1 to 6 years old; older birds actually performed better on spatial learning and memory tasks. Our results therefore suggest that cognitive senescence may be either delayed (potentially appearing after 6 years) or negligible in species with strong selection on cognitive abilities and that food-caching species may present a useful model to investigate mechanisms associated with cognitive senescence.