Sperm whales are named for the milky-white, oily substance called spermaceti found in a large organ in their heads, which whalers during the 18th and 19th centuries mistook for the animal's sperm.
Origin of the Name
Whalers harvesting sperm whales discovered this fluid-filled spermaceti organ, which occupies much of the whale's massive square head, and assumed it was semen due to its appearance. The term "sperm whale" derives from "spermaceti whale," a shortening used in the commercial whaling era. This substance was highly prized for making high-quality candles, lubricants, ointments, and lamp oil before petroleum replaced it.
Spermaceti Organ
The organ can hold up to 2,000 liters of spermaceti and related sperm oil, aiding functions like buoyancy control, sound focusing for echolocation, or stunning prey. Unlike actual sperm, spermaceti is a waxy lipid that solidifies when cooled. Sperm whales, the largest toothed whales, remain identifiable by this unique head structure.
