Breeding
Most terrapins will breed in captivity, as long as they are given the correct care and habitat, specific to that breed. If you don't want your terrapins to breed, then obviously they will need to be separated once they have reached sexual maturity.
The correct homing and care help to promote rapid growth and earlier sexual maturity, this is usually around 5 years for most North American turtles and around 11 years for European and river turtles, any others are usually between these extremes.
The mating season for most turtles is through May, the instinct to mate is triggered when the days begin to lengthen through Spring. Although the turtles may begin flirting on land, they do the deed in the water. The males usually begin the ritual by stroking the females face with his long claws. The turtles then go through a sniffing ritual, checking compatibility, in the wild this would stop interspecies breeding, the male then becomes mildly aggressive before actually engaging in the intercourse.
Something interesting, some females store sperm for up to 4 years, so you could acquire a female, keep her alone, and 3 years later she lays fertilised eggs.
To make a successful mating the turtles should be given the option to hibernate, and the turtles should be in an outside enclosure to make things more natural for them.
If you can't take them outside or they are not hibernating then you should separate the turtles for 2 or 3 months before the breeding seasons, then reunite them, as this happens naturally through hibernation.
(More to come, soon!)