Ambergris is the fragrant substance used in perfumery that is produced in the digestive system of sperm whales.
It is a solid, waxy material associated with the gastrointestinal tract of the sperm whale. Scientists have found squid beaks inside ambergris, supporting the view that it forms around hard, irritating materials the whale has swallowed. Only a small proportion of sperm whales are thought to produce it, which helps explain its rarity.
Fresh material can have a strongly fecal or marine odor. After months or years of floating in seawater, sunlight and oxidation alter it into a harder gray or black substance with a sweet, earthy, animalic scent. Historically, perfumers valued ambergris as a fixative: it helped other fragrance molecules evaporate more slowly and made a perfume last longer.
Ambergris is often confused with amber, the golden fossilized tree resin, but the two are unrelated. It is also not the same as spermaceti, the waxy substance from a sperm whale’s head. Modern perfumery largely uses synthetic ambroxide and related materials instead, avoiding the rarity, legal complications, and conservation concerns associated with natural ambergris.