Britannica Sources used in this answer

Where do cetaceans still have hairs on their bodies?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Illustration showing various cetaceans, including baleen whales like the blue whale, fin whale, humpback whale, gray whale, sei whale, northern right whale, and bowhead whale, as well as toothed whales such as the sperm whale, narwhal, beluga, Baird's beaked whale, killer whale, dolphins, and porpoises. Each species is labeled with its scientific name and typical or maximum length, with a size scale in the corner for reference. — cetacean Whales (order Cetacea).

In adult cetaceans, the hair covering typical of most mammals is drastically reduced, as hair is a poor insulator in water and increases drag during swimming. Instead of a full coat, these mammals rely on thick subcutaneous fat deposits, known as blubber, for insulation.12

When present, hairs on cetaceans are restricted to the head, with isolated follicles found on the lower jaw and the snout. These sparse, stiff hairs are identified as vibrissae—or sensory whiskers—which serve as tactile organs.12