Do whales drink sea water?
This is a really intriguing question! You’re right that Humpback whales are nursing their calves during a period when they’re not eating (except towards the end, when they’re being weaned). This is one of the reasons, it’s believed, that female baleen whales are larger than the males. The answer is fat. Humpback whales store huge energy reserves in their blubber layer – which can be up to a foot thick. During the months when a female is lactating, she’s using that fat reserve to make milk for her baby. At first the milk is exceptionally high in fat, over 50% fat (cow’s milk is 4-5%) but later as the baby grows it becomes more protein and less fatty. In general though, Humpback whales take in their water via the food they eat. Their common prey is small fish such as herring, anchovies or sardines. They also eat plankton like krill or other amphipods. In those times of feeding excess energy is store in the fat, which also stores water. (A camel’s hump is similar, it also stores water but
