新普京娱乐网址

Desirable fathers

作者:鞠簋螯    发布时间:2019-03-07 06:10:03    

FEMALE tree swallows may influence who fathers their offspring by dictating which position males use during sex. Few bird species sport penises, but in those that have one it bends to the left. This is thought to improve the male’s chances of getting sperm into the female’s left-tilted oviduct. Michael Lombardo from Grand Valley State University in Allendale, Michigan, and his colleagues observed hundreds of copulations between tree swallows. These notoriously unfaithful birds are graced with mini-penises. The swallows mounted from the left three times more often than from the right, but Lombardo notes that the female positions her tail to dictate which side the male adopts. This may allow her to manipulate the male’s chances, he told a meeting of the Midwest Regional Animal Behavior Society Conference at Bowling Green, Ohio,

 

Copyright © 网站地图