大象传媒

The red-billed buffalo weaver possesses one of the most bizarre consequences of the force of sexual competition in evolution 鈥� particularly the competition between males to be the one whose sperm fertilises a female鈥檚 eggs. The male of the southern African species boasts a finger-like appendage between his legs. 鈥淭his is seriously weird鈥�, thought ornithologist Tim Birkhead when he first heard about the red-billed buffalo weaver. After receiving a specimen in the post from Africa, stalking the birds in Namibia and raising some in an aviary, Tim thinks he鈥檚 cracked why the males have evolved a false penis. Could it be Nature鈥檚 own tickling stick?