Lactation in cetaceans: litres, fat, weight gain

The richest milk in the animal kingdom

A blue whale produces up to 220 litres of milk a day at 50% fat, the richest composition in the animal kingdom. Its calf gains 90 kg a day. This database compares milk production, composition and growth rates for 12 species, including the human reference.

Going further

Lactation belongs to the reproductive cycle: comparative life cycles, mating systems, social cohesion and demographics.

Lactation beyond the ordinary among marine mammals

Cetacean milk is the richest among mammals: up to 40 to 60% fat in some rorquals, against 4% in the cow. That caloric density is imposed by nursing underwater, which has to be quick to allow breathing. The mother injects the milk under pressure into the calf’s mouth using her mammary muscles.

A female blue whale produces up to 220 litres of milk a day; her calf gains about 90 kg per 24 hours. In odontocetes, lactation often lasts 2 to 5 years and accompanies the learning of hunting techniques, in particular in the common bottlenose dolphin (Tursiops truncatus) and the killer whale (Orcinus orca).