Wikipedia: Except for the aye-aye and the Lac Alaotra gentle lemur, lemurs are seasonal breeders with very short mating and birth seasons influenced by the highly seasonal availability of resources in their environment. Mating seasons usually last less than three weeks each year, with the female vagina opening up only during a few hours or days of her most receptive time of estrus.

Damn. Oh well, back to the drawing board.