When they catch fish, they usually shake the prey in the air and then sometimes eat it whole. Reproduction Otaria byronia are known for their polygynous lifestyle. Mating season begins from early August to December, when males begin to defend their territories aggressively and show interest in females. Mating behavior includes mutual vocalizations, snout contact, smelling, playful biting, and mouth contact. Territories for breeding grounds are usually on beaches of sand, pebbles, or flat rock.
Males prevent females from leaving the beaches until they have mated.
Birth occurs from mid December to early February in the year after mating, with the bulk of births during mid January. The gestation period is about 11.75 months. Usually one pup is born at a time, which averages .80 to .85 meters in length and 10 to 15 kilograms in weight. Male pups tend to be larger than females. However, since mothers seem to not show any gender based nursing difference, this suggests that the energy spent more in sons than daughters is done during gestation.