Mexican fisherman also report that there are very few sharks in the lagoons when the whales are present. The calf's breathing is awakened at birth, but within several hours the animal is making smooth dives. It breathes about twice as frequently as its mother for the first several weeks. The male takes none of the responsibility for newborns. Calves nurse from their mothers for approximately 6 to 8 months, acquiring more independence during the last third of the suckling period.
Females have two teats, one on either side of the genital slit.
Their milk is 50 percent fat. There are no long-term bonds between males and females. Females have been seen breeding with three males in 45 minutes. Northern migration By March, whales are already returning northward along the Oregon Coast. These animals pass the Oregon coast from early March through April.