Noun
A peculiar bitter orange-brown substance, with strong, penetrating odor, found in two sacs between the anus and external genitals of the beaver; castor; -- used in medicine as an antispasmodic, and by perfumers.
Source: Webster's dictionaryA by-product of the trade in beaver pelts was castoreum —the secretion of the animals' anal glands—which was used for its medicinal properties and for perfumes. Source: Internet
They invest much energy in their territories, building their dams and becoming familiar with the area. citation Beavers mark their territories by constructing scent mounts made of mud, debris and castoreum, Rosell, Frank, and Andrezej Czech. Source: Internet