Before anyone says anything, let’s just get one thing straight: No, what I am about to describe to you does not prove a certain biblical story.
Now that’s out of the way, back to the cool story. A female yellow-bellied watersnake has reproduced without a male in sight. If you’ve heard of this male-free reproductive trick before, then you may not be bowled over, but what is particularly interesting here is that this is not the first time this serpent has gone solo. Just last year, the Cape Girardeau Conservation Nature Center resident popped out two little’uns without warning, which were initially confused for vomit, to paint a charming picture.
Carrying on the trend of mistaken identity, this time around an intern thought someone had decided to try and tempt the carnivorous snake with tomatoes, and was rather taken aback when he realized the soft spheres weren’t fruit at all, but instead newly laid membranes.
Prior to last year’s “virgin birth” event, this mode of reproduction was not known in these particular snakes, but it has been documented in quite a few other snakes over the years, including copperheads, cottonmouths, anacondas, Burmese pythons and rainbow boas. But by no means is parthenogenesis (“virgin creation”) limited to snakes: It has been observed in fish, other reptiles, insects, birds and amphibians, to name a few. But this ever-growing list has yet to include mammals.
Parthenogenesis can be considered a type of asexual reproduction, although some regard it as an incomplete form of sexual reproduction. For a long time, this phenomenon was thought to be a product of captivity, but it has now been observed in the wild, and when plenty of males have been available to go about it the traditional way too. So at this stage, it’s unclear why some females go down this route, especially when offspring are often unhealthy or not viable due to an extreme lack of genetic diversity.
But what we do know is that it’s not simply the result of females storing sperm from earlier mating sessions for a rainy day, although one record-breaking shark managed to keep some stashed away for an impressive 45 months, the longest known example for any species of shark. The snake at the Cape Nature Center had been a spinster for eight years, so there’s no way any sperm could have lingered for that long. Instead, the process is made possible by the fusion of an egg with a cell, called a polar body, that gets released at the same time. As National Geographic explains, this means the offspring aren’t exact clones like you would find in asexual reproduction.
Unfortunately, this time the slithery critters didn’t survive, but the two produced last time are still doing well and are helping teach people at the center about “the birds and the bees.”
