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
Castor and Pollux (Prado) into the Prado (catalogue number Catalogue Nr. E.28). The erroneous identification with Antinous generated high interest in the sculpture, with large numbers of copies being produced, largely made in Italy and Northern Europe and based on plaster casts rather than made in Spain and based on the original there. These inevitably stoked the interest by obscuring the fact that the Antinous head was in fact a restoration, instead smoothing the two into a meaningful whole (as did the casts on which they were based). Main site about copies of the Ildefonso (or Castor & Pollux) group : http://www.antinoos.info/copies1.htm Copies Castor