Why sexual coercion is so prevalent in orangutans & how this type of sexual selection may be much more common across animals than often recognized

Orangutan socio-sexual behavior and sexual conflict: Insights for human evolution. Cheryl D. Knott. European Human Behaviour and Evolution Association, 15th Conference, Mar 2021. https://ehbea2021.com/

Abstract: In this talk I reveal how recent research on great ape behavior and physiology provides new insights into the similarities we share with our closest relatives. In particular, I focus on my long-term research studying wild orangutans in Gunung Palung National Park, Indonesia for over 25 years. Orangutans are known for one of the highest rates of sexual coercion, through forced copulation, of any animal. This is coupled with another intriguing phenomenon of having two male morphs, a rare type of male bi-maturism. Females share crucial features of reproductive physiology in common with humans, such as concealed ovulation and menstrual cycle length. In this talk I explore the complexity of male and female reproductive decisions in wild orangutans and the ways that these reveal insights into the evolution of human mating systems. This includes new research from my team on the development of socio-sexual behavior in adolescent females and how the threat of forced copulation, as well possible infanticide risk, impacts female behavior and ranging patterns. I also demonstrate the success of strategies employed by females to avoid undesired sires. These results reveal that, despite high rates of forced copulation, female choice is an important feature of orangutan mating patterns. I also discuss why sexual coercion is so prevalent in orangutans and how this type of sexual selection may be much more common across animals than often recognized. I point to the need for considering comparative data on sexual conflict as we consider the evolution of human mating patterns.