Back to Top Reproduction of Spinner Dolphins Spinner dolphins give birth to a single calf of less than one meter in length. Females can give birth every two to three years after a l0 or 11 month gestation period. Lactation periods have been estimated to last as long as l8 months. Sexual activity in Hawaiian spinner dolphins appears to peak in summer and fall. Mating is not monogamous and seems to involve more than one partner.
Calves are often the most active animals in a school.
It is not uncommon to see a young calf skirt away from its mother for brief periods before rushing back to her side. Calves will sometimes join together to form a central ring within the school where they are often seen chasing, touching, and rolling over one another. Bottlenose dolphins have a distinctive stubby snout or rostrum, with a curved mouthline that looks like an endearing smile. They range from light to nearly black on their back and sides, fading to white on the belly. Nicks in their dorsal fins, and scratches and scars on their backs allow us to identify individual animals.