Castoreum Castoreum Castoreum is a yellowish exudate from the castor sacs of the mature North American beaver ("Castor canadensis") and the European beaver ("Castor fiber"). Beavers use castoreum in combination with urine to scent mark their territory. Both beaver sexes have a pair of castor sacs and a pair of anal glands, located in two cavities under the skin between the pelvis and the base of the tail. The castor sacs are not true glands (endocrine or exocrine) on a cellular level, hence references to these structures as preputial glands, castor glands, or scent glands are misnomers. It is used as
Oily fish Oily fish Oily fish have oil in their tissues and in the belly cavity around the gut. Their fillets contain up to 30% oil, although this figure varies both within and between species. Examples include small forage fish, such as sardines, herring and anchovies, and other larger pelagic fish, such as salmon, trout, tuna, swordfish and mackerel. Oily fish can be contrasted with white fish, which contain oil only in the liver, and much less overall than oily fish. Examples of white fish are cod, haddock and flatfish. White fish are usually demersal fish which live on or near the