Female hatchling American kestrels have a larger hippocampus than males: A link with sexual size dimorphism?

Female hatchling American kestrels have a larger hippocampus than males: A link with sexual size dimorphism?
Behav Brain Res. 2018 Apr 24;:
Authors: Guigueno MF, Karouna-Renier NK, Henry PFP, Head JA, Peters LE, Palace VP, Letcher RJ, Fernie KJ
Abstract
The brain and underlying cognition may vary adaptively according to an organism's ecology. As with all raptor species, adult American kestrels (Falco sparverius) are sexually dimorphic with females being larger than males. Related to this sexual dimorphism, kestrels display sex differences in hunting and migration, with females ranging more widely than males, suggesting possible sex differences in spatial cognition. However, hippocampus volume, the brain region responsible for spatial cognition, has not been investigated in raptors. Here, we measured hippocampus and telencephalon volumes in American kestrel hatchlings and found no significant difference between left and right hemispheres for either hippocampus or telencephalon. Female hatchlings had a significantly larger hippocampus relative to the telencephalon and brain weight than males (~12% larger), although telencephalon volume relative to brain weight and body size was similar between the sexes. The magnitude of this hippocampal sex difference is similar to that reported between male and female polygynous Microtus voles and subspecies of Zonotrichia sparrows. Future research should determine if this sex difference in relative ...

Source: Behavioural Brain Research - April 24, 2018 Category: Neurology Authors: Guigueno MF, Karouna-Renier NK, Henry PFP, Head JA, Peters LE, Palace VP, Letcher RJ, Fernie KJ Tags: Behav Brain Res Source Type: research