This section is 1.40 min long, with soundtrack (see also "SILENT CLIPS")

Chapter size: 17 MB (.mpg) or 3 MB (.mov).

Topics and Behaviours covered: promiscuity, solicitation, harassment, sexual conflict, multiple paternity, mate choice, sperm competition (see commentary below).

Chapter commentary:
Although it is the female who ultimately decides when to mate, there is a fine line between solicitation and harassment. Even then, the other males interfere very little with the mating male, and do not fight with each other. Reduced fighting may be a feature of generations of laboratory breeding, but it is also found in wild rats. Because the female is constantly on the move, males engaged in fighting would rapidly lose her, and therefore loose the opportunity to mate.

This may also be why subordinates are inclined to accept their social ranking in the colony without too much fuss. Even they might have a chance to mate in such an indiscriminate scramble for pole position.

Why do such multi-male - multi-female mating patterns exist? It is clear why males benefit from mating with several females, since it will increase the number of their offspring. But why should females, since females are limited by the number of pups that they can produce? This is not only a feature of harassment, as females, when given the choice, actively choose to mate with several males. Whilst it is still a bit of a mystery, they are several possibilities. For example, females may ensure their eggs are fertilised, by reducing the chance of mating with an infertile male. It may also be a way of inducing competition between males, and ensuring that only the best sperm, or the fittest males, most able to keep up with her, win the scramble competition.

(but sexual conflict does not stop at mating: see next section: "Birth & Death")