Dead Male Guppies Can Make Babies

Female Trinidadian guppies store sperm from males that they mated with and use it to make babies long after the males they mated with died

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Alice Chaos

Despite what television might have you believe, zombies aren’t running around and having romantic interactions with the living. Usually. But one species of fish does reproduce posthumously. Female Trinidadian guppies store sperm from males that they mated with. They store this sperm for a while, long after the males they mated with died. And while scientists have seen this in the lab before, in species like ants, turtles and bats, this is the first time they’ve seen it in the wild.

In a recent study, author Andres Lopez-Sepulcre finally figured out why the number of baby guppies wasn’t adding up to the number of fathers in the stream he was studying. It turned out that females were storing male sperm and having babies with it later. And not just one or two females. As many as a quarter of guppy babies were fathered by dead males. Here’s Live Science with an explanation for why females might do this:

The female guppies live much longer than males, on average, and the females’ ability to store sperm benefits both sexes. Sperm storage allows short-lived males to expand their reproductive lifespan and pass on their genes even after they’re dead. Sperm held within a female’s body may also be able to survive stressful seasonal conditions that adult males cannot.

So storing the sperm might be a technique to maintain the population even when there are no males around to mate with. Gives a new meaning to “until death do us part.”

More from Smithsonian.com:

The Curious World of Zombie Science
The Scariest Zombies in Nature