Sperm whales are generally found in deep water, so they are most likely to be found along the edge of the continental shelf or over canyons and deep basins between banks, as well as on the high seas. The sperm whale is the only living whale whose nostrils are not situated in a position well behind the snout. Its single blowhole, an S-shaped slit, is at the front of the snout, distinctly left of centre. The position of the blowhole causes the bushy blow to angle forward and to the left, which makes it possible to identify sperm whales even at a distance of some miles. The body is dominated by the huge head, which is squarish in profile.
Functional teeth are present only in the narrow, underslung lower jaw.
These massive chunks of ivory were smoothed, engraved, and decorated with intricate patterns or scenes by nineteenth-century whalemen, a traditional American art form known as scrimshaw. There is a substantial difference in size between male and female sperm whales. Males grow to lengths of 18 m or more, while females are rarely more than 12 m long. Old bulls can weigh in excess of 50 tons. Sperm whales are basically brownish gray to black.