The Guppy's Grappling Genital Claws

摘要

Guppies are small freshwater fish found in aquariums throughout the world. They are colourful and are incredibly easy to breed. Unlike many fish that breed by releasing sperm and eggs into the water, male guppies fertilise females by delivering sperm internally. Male guppies do not have a penis. They do, however, have a modified fin that is a penetrating organ known as the gonopodium. The tip of the gonopodium has a set of claws or hooks.