How Much Does a Humpback Whale Eat?
Share
An adult female humpback whale, like the one illustrated with her calf, can weigh roughly 35 tons. That’s about the same weight as five of the largest male African elephants. So how much does a humpback whale eat to stay so big?
Humpback whales spend warmer months in cold water, feeding and storing up fat. During the colder months, they go on one of the longest mammalian migrations to warmer waters to mate and nurse their calves, surviving on their fat stores. Humpback whales feed mostly on krill – small crustaceans roughly half an inch long – filtered through the baleen plates that hang down from their upper jaw. To eat, humpback whales take in large volumes of water and food by expanding the pleats along their throat. The baleen acts as a filter, trapping food in their mouth and allowing water to flow back out as they refold the pleats and close their mouth. Humpback whales in the eastern North Pacific, for example, eat an average of 9 tons of krill a day, almost a quarter of its body weight (Savoca, et al., 2021).
But how did these researchers measure how much a humpback whale eats? Previously, the research community had estimated their caloric needs based on the needs of smaller animals and scaling up, or by inspecting what a deceased whale had in its stomach. Savoca et al. tagged humpback whales with a device that measures the size and density of krill swarms using sound pulses. Based on the size of the whale, the team could calculate how big of a mouthful the whale could take in. Taking the volume of krill-and-water and the density of the krill swarm into account, they could estimate a range of how much krill was consumed per mouthful. They then calculated how much krill per day a whale could eat based on the average number of mouthfuls it took during a feeding session
9 tons of food a day is a whale-y big number. But it makes sense: they need to eat as much as they can to successfully nurse their calves and survive the journey between their feeding and breeding sites.
Additional fun fact: The scientific name for humpback whales is Megaptera novaeangliae. Megaptera means “big-winged” and refers to their long pectoral fins. novaeangliae means “New England” which is where whalers first encountered humpback whales.
Bring your humpback whale sticker home today.
References