The European midwife toad Alytes obstetricans is unusual because the males exhibit parental care. The male carries eggs (possibly from several females) wrapped around his hind limbs until they are ready to hatch. The mating pattern of this species is not random; a significant correlation was found between male snout-vent length and dorsal egg count. Bigger males have larger broods and therefore father more offspring. Because brood size does not appear to affect egg hatching success, larger males may enjoy higher fitness. This non-random pattern of mating may be achieved by male intra-sexual competition, and both male and female mate choice.