A few species copulate, but most fertilize their eggs externally. Male garter snakes often copulate with dead females. Males may either defend their mates or try to forcibly copulate with them. In captivity, mating pairs will often copulate several times during oestrus. This species is a promiscuous breeder and both sexes copulate with multiple partners. In general, both sexes will copulate with several mates during mating season. Female beetles vary in which males they choose to copulate with. Males also copulate at shorter intervals than females. Other males usually do not copulate with the female. Following a successful mating display, the pair will copulate once. These lowest ranking males would get no opportunity to copulate otherwise. This prevents future males from attempting to copulate with her. After both snails have fired their darts, the snails copulate and exchange sperm. They intertwine facing their bellies together and begin to copulate for 40 seconds. Members of both sexes may copulate with several mates over the course of several years.