The XX Factor

Every Sperm Is Super-Sized

And you thought human sex was messy: A paper published in Science yesterday introduces the world to a bunch of tiny, ancient crustaceans that produced relatively massive sperm . And has pictures ! (Don’t worry; they’re safe for work-and oddly beautiful.)

Researchers in Europe used cutting-edge “synchrotron X-ray holotomography” to non-invasively examine 100-million-year-old fossilized ostracods . The descendants of these millimeter-long creatures produce giant sperm-up to 10 times as big as their bodies, in some cases-and the new fossil images prove that their ancestors had the plumbing to do the same.

Giant sperm can give males a competitive edge when females end up mating with more than one partner; the trait is seen in some bird, insect, worm, and primate species, as well. Thankfully, humans never went down that evolutionary route: To match the aforementioned group of modern ostracods, our brothers would have to produce sperm nearly 56 feet long.

Of course, that’s nothing compared to the humble fruit fly. Uncoiled, a Drosophila bifurca sperm measures almost 6 centimeters-or a little more than 130 feet, when scaled up to human size. Takashi Murakami would be proud . (Now, that’s not SFW.)