Sperm whale

Natural history

The male and female sperm whales differ greatly. The male is typically 30 to 50 percent larger than the female and weighs about twice as much. The male’s lower jaw has 18 to 26 pairs of large (up to 8 inches, or 20 cm, long) cone-shaped teeth that are designed for grasping slippery prey such as squid rather than cutting. The female has smaller and fewer teeth.

Conservation

In the past, whalers hunted sperm whales for spermaceti, fine oil used to make high-quality candles and lubricants. Estimates vary widely regarding the present population of sperm whales. The American Cetacean Society states: "Most recent estimates suggest a global population of 300,000 animals, down from about 1,100,000 before whaling." The sperm whale population is slow to recover because these animals mature late and have few offspring. Sperm whales are listed on the U.S. Endangered Species List. Sperm whales are listed as “vulnerable” by the International Union for the Conservation of Nature and Natural Resources (IUCN). Hunting of sperm whales is banned nearly worldwide.

Another threat is the growing rate of plastic pollution. A November 2022 study showed that per day, a krill-obligate blue whale may ingest 10 million pieces of microplastic, while a fish-feeding humpback whale likely ingests 200,000 pieces of microplastic. Moreover, gray whales and some populations of humpback whales suction feed in the sediment to extract invertebrates. As the seafloor is a primary sink for synthetic marine debris, there may be considerable risk to gray and humpback whales feeding in the substrate.

For species like whales that are struggling to recover from historical whaling alongside other anthropogenic pressures, these findings show that more attention needs to be paid to the threatening presence of plastics in our waters.

Cool facts

• The sperm whale was celebrated as the "great white whale" named Moby Dick in Herman Melville's novel of that name.
• Scientists believe that the sharp beaks of consumed squid lodged in the whale's intestine leads to the production of the waxy substance called ambergris. Lumps of ambergris are found in the intestines of a dead sperm whale or as flotsam on the sea or coast. When fresh, it has a foul smell, but when dried, it has a strong, musklike odor. Its primary use was as a fixative in fine perfumes, and ambergris was once worth its weight in gold. Today it's illegal to possess, buy or sell ambergris in the United States.
• Sperm whales "see" in the dark depths of the ocean by using sonar or echolocation. The whales focus sound waves toward objects and prey. When sound waves echo back, they tell a sperm whale the object’s position, distance and size.
• A sperm whale can dive to 8,202 feet (2,500 m) and stay under water for up to 90 minutes.
• Gestation for this species can be up to 18 months. Females may nurse their calves for over two years, but some animals have been found to still be nursing at 13 years of age.