spermaceti Highly vascular tissue, filled with a mixture of fatty esters (oils) which solidify at about 32°C, produced by Physeteridae (sperm whales) and stored in the upper part of an enlarged snout. A full-grown sperm whale may carry one tonne of spermaceti. The function of spermaceti is not known with certainty, but since its density changes as it liquefies and solidifies it may permit heat loss from the body and help provide neutral buoyancy to the animal, and it may contribute to the production of the sounds by which the animal echo-locates.

spermaceti Highly vascular tissue, filled with a mixture of fatty esters (oils) which solidify at about 32°C, produced by sperm whales (Physeteridae) and stored in the upper part of an enlarged snout. A full-grown sperm whale may carry one tonne of spermaceti. The function of spermaceti is not known with certainty, but since its density changes as it liquefies and solidifies it may permit heat loss from the body and help provide neutral buoyancy to the animal, and it may contribute to the production of the sounds by which the animal echolocates.

spermaceti fatty substance obtained from the sperm whale. XV. — medL. spermacētī (so named from an erron. notion of the nature of the substance), f. sperma SPERM + cētī, g. of cētus — Gr. kêtos whale; attrib. in s. whale (XVII), shortened to sperm whale (XIX)
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