How do sperm whales dive so deep, and what is the wax in their heads for?
A sperm whale can hold its breath for over an hour in the dark, and nobody is sure what the barrel of wax in its head is for.
โถ Start the storySperm whales dive deep by being built to be squeezed: their flexible ribcage lets the lungs collapse, which reduces intake, and their metabolism can slow to conserve oxygen. A sperm whale can plunge to 2,250 m, third deepest of any mammal, and usually dives between 300 and 800 m, sometimes 1 to 2 km. Dives can last more than an hour.
2,250 m
They go down for food, mainly medium-sized squid, though they also take giant and colossal squid, octopuses and some fish. Nobody has ever seen a fight between a sperm whale and a giant squid, but white scars on the whales are believed to come from the big squid.
What about the wax? A sperm whale's head holds the spermaceti organ, which may contain as much as 1,900 litres of spermaceti. Scientists have proposed that the organ controls , that it focuses the whale's echolocation clicks, or both. The buoyancy idea says the whale heats the wax to float and cools it with seawater to sink, but recent research has questioned it. Disagreement still exists on what spermaceti is for.
Humans, meanwhile, found plenty of uses for it. The waxy stuff was first thought to be whale semen, which is how the sperm whale got its name, and whalers extracted it for cosmetics, textiles and candles.
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Recap
Sperm whales are built to be squeezed on deep dives, and the wax in their heads is still a puzzle.
๐ก A trick to remember it ยท A squeezable ribcage for the trip down, a barrel of mystery wax for the head.
Surprising fact ยท Candlepower was defined by a spermaceti candle.
Sources (2)
No source, no claim. Every fact in this lesson (17 claims) cites at least one of these.