Paul Bentzen

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ScienceShot: Fatherhood From Beyond the Grave

Men who become dads in their 50s may feel studly, but they've got nothing on the wild guppy. New research shows that the male Trinidadian guppy (Poecilia reticulata), the ancestor of the common aquarium resident, can become a father long after death. Scientists spiked a guppy-free stretch of stream in Trinidad with 38 male and 38 female fish. Every month, they used butterfly nets and traps baited with dog food to capture the guppies in the study area—which was bounded by waterfalls, ensuring no immigrants or escapees—and then analyzed their DNA. The survey showed that almost 14% of the 540 tallied births took place after dad had died, and that a male guppy could become a father 8 months, roughly 75 years in human terms, after his demise. That allowed half of the fish to sire offspring from beyond the (watery) grave, the team reports online today in the Proceedings of the Royal Society B. The male has the female to thank for this supernatural ability. A female guppy can store her consort's sperm for months in a tiny pocket inside her ovaries, which is lucky, because females live much longer than males. The arrangement benefits both sexes: Females can have babies even if the dating scene is grim, and males can reproduce for longer than their lifespan.

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