Sexual cyclicity in captive lowland gorillas.
Oppositely sexed pairs of gorillas exhibit some behavior indicative of higher cognitive functioning, such as individual partner preferences and varied copulatory positions, but also mate in a cyclic manner closely related to the degree of female genital swelling. The latter finding is contrary to predictions based on their advanced position in phylogeny.
D000818:Animals; D005075:Biological Evolution; D003307:Copulation / Q000502:physiology*; D005260:Female; D006071:Gorilla gorilla / Q000502:physiology*; D007742:Labial Frenum / Q000502:physiology; D008297:Male; D010152:Pair Bond; D012726:Sexual Behavior, Animal; D014828:Vocalization, Animal