Sexual dimorphism in linear measures of the corpus callosum in cats

The sexual dimorphism in the linear measures of the corpus callosum was studied in adult cats. In absolute measures, males had significantly larger genu, isthmus, and splenium than females; the mean absolute lengths were not significantly different in males and females. There were significant positive linear correlations between callosal measures and brain weight in the male and female cats, (no significant correlation between isthmus width and brain weight in females). The mean callosal measures predicted from brain weights in regression equations were found to be significantly greater in males than in females. This sexual dimorphism in callosal measures of cats showed similarities with rats, but not with humans. It was suggested that this may be due to cognitive differences between animal and human brains as well as brain development under relatively simple environmental factors such as gonadal hormones (testosterone) in animals compared to human brains.