page_title: American mink
section_title: Reproduction and development
hierarchical_section_title: American mink / Behaviour / Reproduction and development
caption_attribution_description: English: Young American Mink (Neovison vison), Poland. Deutsch: Nerzwelpen (Neovison vison), Polen. Polski: Młode hodowlane norki amerykańskie (Neovison vison).
context_page_description: The American mink is a semiaquatic species of mustelid native to North America, though human intervention has expanded its range to many parts of Europe and South America. Because of range expansion, the American mink is classed as a least-concern species by the IUCN. Since the extinction of the sea mink, the American mink is the only extant member of the genus Neovison. The American mink is a carnivore that feeds on rodents, fish, crustaceans, frogs, and birds. In its introduced range in Europe it has been classified as an invasive species linked to declines in European mink, Pyrenean desman, and water vole populations. It is the animal most frequently farmed for its fur, exceeding the silver fox, sable, marten, and skunk in economic importance.
context_section_description: The American mink is a promiscuous animal that does not form pair bonds. The start of mating season ranges from February in its southern range to April in the north. In its introduced range, the American mink breeds one month earlier than the European mink. Males commonly fight during the mating season, which may result in the formation of loose, temporary dominance hierarchies governing access to receptive females. The mating season lasts for three weeks, with ovulation being induced by the presence of males. The mating process is violent, with the male typically biting the female on the nape of the neck and pinning her with his forefeet. Mating lasts from 10 minutes to four hours. Females are receptive for seven- to 10-day intervals during the three-week breeding season, and can mate with multiple males. Along with the striped skunk, the American mink is among the only mammals to mate in spring that have a short delay before implantation. This delayed implantation allows pregnant minks to keep track of environmental conditions and select an ideal time and place for parturition.
  The gestation period lasts from 40 to 75 days, with actual embryonic development taking place after 30–32 days, indicating implantation delay can last from eight to 45 days. The young are born from April to June, in litters consisting of four kits on average. The litters are often multiply sired. Exceptionally large litters of 11 kits have been recorded in Tartaria and 16 in the United States. The kits are blind at birth, weighing six grams and possessing a short coat of fine, silver-white hairs. The kits are dependent on their mother's milk, which contains 3.8% lipids, 6.2% protein, 4.6% lactose and 10.66% mineral salts. Their eyes open after 25 days, with weaning occurring after five weeks. The kits begin hunting after eight weeks of age, but stay close to their mother until autumn, when they become independent. Sexual maturity is attained during the kit's first spring, when they are about 10 months old.
caption: American mink kits
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