Sex itself can be very aggressive. In many different mammalian species sexual encounters look like fights, sometimes accompanied by thrashing about, loud noises, and (in cats) mock biting, scratching, then a final act of pushing away that looks distinctly unfriendly. However, even after such displays, male and female cats such as lions remain in each other’s proximity for multiple matings, so evidently the act of reproduction is not aversive to them.
Perhaps one reason sex and aggression alternate so easily is that they are related by evolution and biology. In Chapter 8 (p.701) we discussed how winning a fight increases levels of the sex hormone, testosterone, in primate species. Therefore the male winner of a fight benefits in reproductive success: he has more access to females, and he has higher levels lil-waynesongs.com of male hormone that fosters greater degrees of sexual activity as well as aggression.
However, not all primates are aggressive. In at least one species, aggression takes second place to sex. The “pygmy chimpanzee” or bonobo (bo-NO-bo) is the human’s closest relative among primates. Among bonobos, sex is frequent, bisexual, and promiscuous. Almost anything exciting (such as anticipated food) causes Bonobos to initiate sexual contacts with one another. This makes bonobos unlike other types of chimpanzees, who fight more and have sex less.