Whales inhabit every ocean. These diverse marine mammals navigate complex underwater environments. Understanding their early development offers insight into their extraordinary existence.
The Term “Calf”
The universally accepted term for a younger whale is a “calf”. This applies to all species, from the blue whale to the beluga and orca. This naming convention extends to other large mammals like elephants, hippos, rhinoceroses, giraffes, and bovines, whose young are also called calves. The use of “calf” highlights a shared characteristic: being large, live-born, and initially dependent on maternal care.
Early Life of a Whale Calf
Whale calves are born underwater, typically tail-first, minimizing drowning risk during birth. The mother, sometimes aided by other females, often guides the calf to the surface for its first breath. At birth, a calf is large, about a quarter of its mother’s length, and can swim immediately, staying close for protection. For example, a blue whale calf can be 7 meters (23 feet) long and weigh 2,700 to 3,600 kg (6,000 to 8,000 lbs).
Calves are immediately dependent on their mother. They nurse frequently from nipples concealed in the mother’s abdominal mammary slits. The mother ejects thick, high-fat milk (13% to 53% fat), significantly more than land mammals. This nutrient-rich milk facilitates rapid growth; a blue whale calf can gain about 90 kg (200 lbs) per day. The mother’s protective behaviors, such as shielding the calf from predators, are important for its survival.
Development Beyond Calfhood
As whale calves mature, they transition beyond complete dependence. The weaning process, where calves shift from milk to solid food, varies by species. Baleen whale calves may nurse for 4 to 11 months, often weaning by their first summer in feeding grounds. Some toothed whales, like belugas, have protracted nursing periods, remaining partially reliant on milk into their second or third year. Sperm whale calves, for example, may stay with their mothers for 8 to 10 years, learning deep-diving and social skills.
Developing independence involves learning survival skills like foraging and navigating their habitat. While some species, like humpbacks, separate after about a year, others, particularly killer whales, exhibit long-lasting maternal bonds, with offspring sometimes remaining with their mothers for life. This extended maternal care, especially in orcas, allows for the transmission of complex social behaviors and hunting strategies important for their long-term survival.