- Clements, J. F., T. S. Schulenberg, M. J. Iliff, B.L. Sullivan, C. L. Wood, and D. Roberson. 2012. The eBird/Clements checklist of birds of the world: Version 6.7. Downloaded from http://www.birds.cornell.edu/clementschecklist/downloadable-clements-checklist
Habitat and Ecology
Molecular Biology and Genetics
Barcode data: Oxyura vittata
Below is the sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.
See the BOLD taxonomy browser for more complete information about this specimen.
Other sequences that do not yet meet barcode criteria may also be available.
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Statistics of barcoding coverage: Oxyura vittata
Public Records: 1
Specimens with Barcodes: 1
Species With Barcodes: 1
IUCN Red List Assessment
Red List Category
Red List Criteria
It is notable for possessing, in relation to body length, the longest penis of all vertebrates; the penis, which is typically 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. It is theorized that the remarkable size of their spiny penises with bristled tips 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, ducks have a long corkscrew penis, and the females have a long corkscrew vagina, which spirals in the opposite direction. Scientists have suggested that males use their penises to lasso reluctant females. The males often try to force copulation, but the complex mating geometry allows the females to retain control—most forced copulations do not result in successful fertilization.
- BirdLife International (2012). "Oxyura vittata". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013.
- McCracken, Kevin G. (2000). "The 20-cm Spiny Penis of the Argentine Lake Duck (Oxyura vittata)" (PDF). The Auk 117 (3): 820–825. doi:10.2307/4089612.
- 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.
- Found! The longest bird penis ever › News in Science (ABC Science)
- Duck genitals locked in arms race | COSMOS magazine
- Evolutionary Oddities: Duck Sex Organs > National Geographic
- 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.