Nimbaphrynoides are unique among frogs

In explosive breeders, the first male that finds a suitable breeding location such as a temporary pool, calls loudly and other frogs of both sexes converge on the pool. Explosive breeders tend to call in unison creating a chorus that can be heard from far away. The spadefoot toads (Scaphiopus spp.) of North America fall into this category. Mate selection and courtship is not as important as speed in reproduction. In some years, suitable conditions may not occur and the frogs may go for two or more years without breeding.[103] Some female New Mexico spadefoot toads (Spea multiplicata) only spawn half of the available eggs at a time, perhaps retaining some in case a better reproductive opportunity arises later.[105]

At the breeding site, the male mounts the female and grips her tightly round the body. Typically, amplexus takes place in the water, the female releases her eggs and the male covers them with sperm; fertilization is external. In many species such as the Great Plains toad (Bufo cognatus), the male restrains the eggs with his back feet, holding them in place for about three minutes.[103] Members of the West African genus Nimbaphrynoides are unique among frogs in that they are viviparous; members of the Tanzanian genus Nectophrynoides are the only frogs known to be ovoviviparous. In both cases, fertilization is internal and females give birth to fully developed juvenile frogs