The economy of winter: phenotypic plasticity in behavior and brain structure.
Mobile animals must learn the spatial distributions of resources. The cost of foraging increases dramatically for temperate-zone animals during the winter. Two strategies may be used to balance the energetic budget: reducing costs of foraging and reducing need to forage. Both strategies are correlated with changes in brain structure, specifically in the hippocampus, a fore-brain structure used by birds and mammals to map spatial distributions of resources. Small mammals that reduce their need to forage, through hibernation or reduction in body size, show a specific reduction in the structure and size of the hippocampus. The costs of foraging can be also decreased by migration to better foraging conditions or by food-storing, both of which decrease the temporal heterogeneity of food resources. Both of these latter strategies are associated with increased hippocampal structure; for food-storing birds, this increase is a seasonal phenomenon. Thus not only behavior, but also learning ability and even brain structures in adult animals, may be phenotypically plastic in response to the changing demands of the environment.
Jacobs
L F
LF
Department of Psychology, University of California at Berkeley 94720-1650, USA.
D000222:Adaptation, Physiological; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology; D006624:Hippocampus / Q000033:anatomy & histology*; D009473:Neuronal Plasticity; D012621:Seasons