Japanese macaque
Although SDN is much related to sexual partner preferences in males, it does not show the same relationship to partner preferences in females. Evidence shows that SDN in medial preoptic area is not the prerequisite for the expression of male-typical sexual behaviour and sexual partner preferences in females. One piece of evidence comes from the study on female Japanese macaque, which routinely court, mount (with pelvic thrust), compete for, and even prefer certain female sexual partners over certain males. The part of the brain examined is the anterior hypothalamic nucleus (AHdc), a homologue of SDN-POA. Comparison of the AHdc nucleus volumes between Japanese macaque and rhesus macaque (a closely related sister species of Japanese macaque) shows that there is no significant difference between the volume of AHdc in more male-typical macaques and that in female-typical macaques.