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Amphibian Girlbosses Are Running a Giant Stolen Sperm Ring

The all-female mole salamanders of the Great Lakes don't need no man, but they do need all the sperm he’s left lying around for their biologically confounding reproductive process

Anyone looking for a plot for their girlboss feminist sci-fi (lookin’ at you, Margaret Atwood) should look for inspiration in the procreation habits of a distinct species of Midwestern amphibians. More specifically, to a group of female unisexual mole salamanders, who’ve evolved to procreate without men. Talk about girls running the world, am I right!!!

This intriguing fact was the topic of a recent r/todayilearned post on Reddit, which detailed how the all-female mole salamanders in the Great Lakes actually steal sperm in order to reproduce. The thread links to a 2009 study published in the science journal Nature, in which researchers explain that this mode of reproduction is called kleptogenesis (think: kleptomania but for reproduction), and that the salamanders take semen from five different species of other salamanders in the genus Ambystoma. To be fair, as Science Friday reports, these species do “leave packets of sperm lying around.”

Once they’ve acquired the sperm, the salamanders combine it to fertilize their eggs, before discarding the sperm genome and developing their all-female offspring asexually. They also tend to combine the sperm from the different species — those being: blue spotted, streamside, tiger, jefferson and small-mouthed salamanders — meaning the unisexual offspring can have differing genome combinations.

According to Science Friday, the all-female lineage can grow twice as fast as one that has both males and females — the former will eventually “swamp out, outcompete and beat” the latter — and also avoids the “two-fold cost” of both making males and losing the resources they take away from females.

One redditor more eloquently described the process: “Dude salamanders leave little packets of sperm all around and then the females search it out and absorb it. They can pretty much use any spunk from the five or so different species around and maybe even do some mixing.

It’s like a sexy scavenger hunt for the female salamanders.”

In another, particularly profound comment, one person wrote: “An entire species surviving with what amounts to amphibian cum socks. Truly a wild, wild world.”

The discovery of the unisexual salamanders unique reproduction method only came to light in the last few decades, with scientists previously believing that the female lineage were hybrids. It was only when doing genetic analysis that they found some offspring to be exact clones of their mothers, while others had up to five extra pairs of chromosomes from the “fathers.” 

Rob Denton, a professor of biology at Marian University, described a “human example” to Great Lakes Now: “It’s like if you were to take a sample of my DNA and it had a set of chromosomes from my mother and father, but then additional sets from an orangutan and chimpanzee and gorilla.” As the publication wrote, “Those vastly different ape species are approximately how distantly related all the species of mole salamanders are from one another.”

Sadly, the unisexual eggs have a higher mortality rate than their salamander counterparts, but a lower capacity for physical endurance (something scientists tested by making them walk on tiny treadmills — cute!). Still, the whole lineage manages to survive.

Maybe humans will one day evolve to be like the all-female mole salamanders. If so, our future, as one redditor predicted, may soon be captioned: “Out here stealing sperm from different species of men with the girlies. Just Friday night things.”