Which whale species is known for its distinctive 'square' head?

The sperm whale is the whale species known for its distinctive square head. Its enormous block-shaped head can make up roughly one-quarter to one-third of the animal’s total length, giving it a profile unlike that of any other living whale.

The head houses the spermaceti organ, a large structure filled with a waxy substance historically called spermaceti. Whalers once prized this material for candles, lamps, and lubricants, helping drive the commercial sperm-whaling industry. The organ is also associated with the whale’s powerful sound production and echolocation system.

The sperm whale’s blunt, square snout and narrow lower jaw are especially recognizable at the surface. Its single blowhole sits near the front of the head and slightly to the left, producing a distinctive angled spout.

Pygmy and dwarf sperm whales also have squared heads, but they are much smaller members of the sperm-whale family. In a general trivia question about the famous “square-headed whale,” however, sperm whale is the canonical answer.