The Argentine Lake Duck with the 42.5 cm Penis
I bet most of you didn't know birds have phalluses, but some do, including water fowl like ducks and North American scientists have discovered the longest bird penis ever - a 42.5cm organ belonging to a ducky.
According to Nature Magazine, Dr. Kevin McCracken, of The University of Alaska, and colleagues, found a duck with a penis the length of his whole body, nearly half a meter long. "This has extended an earlier estimate of the length of the duck's corkscrew-shaped penis which was 20cm."
The male of most bird species does not posess a penis because penile development and growth in most bird species is inhibited by estrogens. These birds mate by touching genital openings (cloaca) or exchanging the proverbial "cloacal kiss." However, water fowl, inclduing a number of duck species and ostriches have penises.
"Dr. McCracken and colleagues speculate that the giant penis may be an example of "runaway" sexual selection, where female preference drives male anatomy to ever-greater extremes, as in the peacock's tail.
"The authors write that this species of duck is 'promiscuous and boisterous in their sexual activity,' which means that there is likely to be stiff competition by drakes to be the father of ducklings.
"One finding in support of this idea, they suggest, is that the drake's penis has a brush-like tip, which they say the males probably use to scrub the sperm of previous mates from the female's oviduct.
"The authors acknowledge that many questions remain: How much of the penis
does the drake actually insert? And does the anatomy of the female make
them unusually difficult to inseminate?"