Lake Duck

Lake Duck
Lake Duck
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Anseriformes
Family: Anatidae
Subfamily: Oxyurinae
Genus: Oxyura
Species: O. vittata
Binomial name
Oxyura vittata
(Philippi, 1860)

The Lake Duck (Oxyura vittata) is a small South American stiff-tailed duck. It is also called the or Argentine Blue-bill, Argentine Lake Duck, or Argentine Ruddy Duck.

The Lake Duck occurs in Argentina, Chile, Paraguay, and Brazil in southern South America.[1]

It is notable for possessing, in relation to body length, the longest penis of all vertebrates; the penis, which is coiled up in flaccid state, can reach about the same length as the animal itself when fully erect, but more commonly is about half the bird's length.[2][3] It is theorized that the remarkable size of the spiny penis with its bristled tip may have evolved in response to competitive pressure in these highly promiscuous birds, removing sperm from previous matings in the manner of a bottle brush.

Although most male birds have no penis,[4] ducks have a long corkscrew penis, and the females have a long corkscrew vagina, which spirals in the opposite direction.[5] The males often try to force copulation, but the complex mating geometry allows the females to retain control—most of the forced copulations do not result in successful fertilisation.[6]


  1. ^ a b BirdLife International (2009). "Oxyura vittata". IUCN Red List of Threatened Species. Version 2011.1. International Union for Conservation of Nature. 
  2. ^ McCracken, Kevin G. (2000). "The 20-cm Spiny Penis of the Argentine Lake Duck (Oxyura vittata)" (PDF). The Auk 117 (3): 820–825. 
  3. ^ McCracken, Kevin G.; Wilson, Robert E.; McCracken, Pamela J.; Johnson, Kevin P. (2001). "Sexual selection: Are ducks impressed by drakes' display?" (PDF). Nature 413: 128. doi:10.1038/35093160. 
  4. ^ Found! The longest bird penis ever › News in Science (ABC Science)
  5. ^ Duck genitals locked in arms race | COSMOS magazine
  6. ^ Brennan, Patricia L. R.; Prum, Richard O.; McCracken, Kevin G.; Sorenson, Michael D.; Wilson, Robert E.; Birkhead, Tim R. (2 May 2007). "Coevolution of Male and Female Genital Morphology in Waterfowl". PLoS ONE 2 (5): e418. doi:10.1371/journal.pone.0000418. 

External links

Wikimedia Foundation. 2010.

Look at other dictionaries:

  • lake duck — noun common scaup of North America; males have purplish heads • Syn: ↑lesser scaup, ↑lesser scaup duck, ↑Aythya affinis • Hypernyms: ↑scaup, ↑scaup duck, ↑bluebill, ↑broadbill * * * …   Useful english dictionary

  • Duck Lake, Nova Scotia — Map of all coordinates from Google Map of all coordinates from Bing Export all coordinates as KML …   Wikipedia

  • Duck Lake, Saskatchewan — Town of Duck Lake   Town   Duck Lake Town Office …   Wikipedia

  • Duck Lake No. 463, Saskatchewan — See also: Duck Lake (disambiguation) Duck Lake Regional Interpretive Centre in Duck Lake Duck Lake No. 463 is a rural municipality in the Canadian province of Saskatchewan, located in the Census Division 15. The seat of the municipality is… …   Wikipedia

  • Duck Lake State Park — Duck Lake State Park …   Wikipedia

  • Duck Lake — may refer to: United States Duck Lake (California), a lake in John Muir Wilderness, California Duck Lake (Illinois), a lake in Illinois Duck Lake (Minnesota), a lake in Blue Earth County, Minnesota Duck Lake (Iowa), a lake in Allamakee County,… …   Wikipedia

  • Duck Mountain Provincial Park (Saskatchewan) — Duck Mountain Provincial Park Provincial park Countries Country, Canada States Province, Saskatchewan Regions Rural Municipality, Cote No. 271 / …   Wikipedia

  • Duck Mountain Provincial Park (Manitoba) — Duck Mountain Provincial Park Provincial park Country …   Wikipedia

  • Duck-billed Buntingi — Conservation status Critically Endangered (IUCN 2.3) Scientific classification …   Wikipedia

  • Duck Lake (Vancouver Island) — Duck Lake Location Vancouver Island, British Columbia Coordinates 49°08′29″N …   Wikipedia