This is true of many bird species, though lots of birds still have some kind of phallus for delivering sperm. Ducks have a crazy looking spiral penis, that in some species, can be longer than the duck's body. The penis falls off after mating season, and he grows a new one every year.
The female duck has a vagina that also spirals, in the opposite direction.
There have been some crazy studies on how this works. The male's penis sort unrolls outwards, explosively, and can fill just about any shape. There are videos of researchers getting a duck all excited into various plastic tubes of all manner of shape.
roberttheaxolotl t1_j06mfc8 wrote
Reply to TIL that roosters don’t have a penis. They pump their sperm into females using a 'cloacal kiss' by [deleted]
This is true of many bird species, though lots of birds still have some kind of phallus for delivering sperm. Ducks have a crazy looking spiral penis, that in some species, can be longer than the duck's body. The penis falls off after mating season, and he grows a new one every year.
The female duck has a vagina that also spirals, in the opposite direction.
There have been some crazy studies on how this works. The male's penis sort unrolls outwards, explosively, and can fill just about any shape. There are videos of researchers getting a duck all excited into various plastic tubes of all manner of shape.