Bird penises start strong, wither away

Bird penises start strong, wither away

Male chickens lose phalluses before hatching

By Cristy Gelling, 11:53 AM June 6, 2013

Some ducks have penises longer than their bodies, while chickens make do with a tiny bump. The vast size difference between the two types of fowl is due to a wave of cell death during chicken development, researchers report June 6 in Current Biology.

Although the ancestors of birds had penises, 97 percent of bird species have phalluses so small that they can’t insert into the female genitalia. Martin Cohn of the University of Florida and his colleagues found that in chick embryos, a gene tu...

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