Why Did the Rooster Lose Its Penis?

Why did so many birds ditch penises? Maybe it was natural or sexual selection, an accident, or in exchange for something way more useful to them. Whatever the reason, penis loss goes to show that internal fertilization doesn’t require a penis.

Hosted by: Michael Aranda

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Images:
https://www.youtube.com/watch?v=rT3HoJJA_kg
https://en.wikipedia.org/wiki/File:Rattlesnake_Hemipenes.jpg
https://commons.wikimedia.org/wiki/File:Europasaurus_holgeri_Scene_2.jpg