Reproduction

 

--- gray whale breeding occurs mostly in the winter to early spring while near the surface and in
       warm water
--- the gestation period is about 13.5 months and the calf is born head first (unusual for

       cetaceans) and near the surface of the warm, shallow waters
--- the newborn instinctively swims to the surface within 10 seconds for its first breath; it is helped

       by its mother, using her flippers
--- within 30 minutes of its birth the baby whale can swim
--- the newborn calf is about 15 feet long and weighs about 1-1.5 ton
--- twins are extremely rare (about 1% of births); there is almost always one calf
--- the baby is nurtured with its mother's fatty milk (53% fat) and is weaned in about 7-8 months
--- the mother and calf may stay together for about a year
--- calves drink 50-80 pounds of milk each day
--- gray whales reach maturity at 8 years
--- growth stops at age 40 years old
--- mature females give birth every other year in the warm lagoons off Baja, Mexico

back