Polycerates (meaning "many-horned") are animals with more than two horns.
Polycerate sheep breeds include the Hebridean, Icelandic, Jacob, Manx Loaghtan, Boreray and the Navajo-Churro. One example of a polycerate Shetland sheep was a ram kept by US President Thomas Jefferson for several years in the early 19th century in front of the White House. In the spring of 1808 this ram attacked several people who had taken shortcuts across the square, injuring some and actually killing a small boy. Because of selective breeding, polycerate sheep are increasingly rare in the British Isles and Spain, but some breeds can still be found in Asia. One example is the blackfaced sheep of Tibet.
There have been incidents of polycerate goats (having as many as eight horns), although this is a genetic rarity thought to be inherited. The horns are most typically removed in commercial dairy goat herds, to reduce the injuries to humans and other goats.
- The Odd Saga of the American and a Curious Icelandic Flock". Google Books. Retrieved May 5, 2012.
- Craig Glenday (30 April 2013). Guinness World Records 2013. Bantam Books. pp. 81–. ISBN 978-0-345-54711-8.
- [Monticello web page http://www.monticello.org/site/plantation-and-slavery/sheep]
- David Low (1845). On the Domesticated Animals of the British Islands: Comprehending the Natural and Economical History of Species and Varieties; the Description of the Properties of External Form; and Observations on the Principles and Practice of Breeding. Longman, Brown, Green & Longmans. pp. 39–.
- Shuttle, Spindle and Dyepot. Handweavers Guild of America, Incorporated. 1981.
- Agricultural & Horticultural Society of India (1846). Journal. pp. 206–.
- Asiatic Society (Calcutta, India) (1848). Journal of the Asiatic Society of Bengal. Bishop's College Press. pp. 1005–.
- Kim Pezza (26 November 2013). Backyard Farming: Raising Goats: For Dairy and Meat. Hatherleigh Press. pp. 112–. ISBN 978-1-57826-474-2.
- Ackermann, R. R.; Brink, J. S.; Vrahimis, S.; De Klerk, B. (29 October 2010). "Hybrid wildebeest (Artiodactyla: Bovidae) provide further evidence for shared signatures of admixture in mammalian crania". South African Journal of Science 106 (11/12): 1–4.