We recently watched one of Australia's redback spiders snare a serpentine meal, but impressive as that feat was, it looks like the tiny eight-legger has some competition. For the first time ever, scientists have documented a wild tarantula tucking into a snake – and this one was a foot long.
Like many amazing discoveries, this one happened by chance. Federal University of Santa Maria graduate student Leandro Malta Borges and his colleagues were surveying Serra do Caverá, a region in southern Brazil renowned for its stunning grasslands, when they happened upon the twosome under a rock.
The arachnid is Grammostola quirogai, a species recognised for being one of the world's longest-living tarantulas. As much as we know about them, however, snakes were not thought to be on their menu.
While we'd love to see a scurrying tarantula actively hunt such large prey, it's more likely that the victim's unfortunate end was a case of bad luck. "[These] spiders use rocks in contact with the ground as retreats, mainly the sedentary adult females," the team explains in a recently published description of the incident. "They rarely leave the safety of these holes, which are coated with thin web layers." Our best guess, then, is that the unwitting snake (Erythrolamprus almadensis) sought refuge in the spider's bunker.
By the time the grisly pair was found, both the head and middle regions of the snake's body had begun decomposing – but not because of post-mortem rot, as you might imagine. Digesting is energy-expensive, so many spiders employ an evolutionary workaround to avoid unnecessary work. By pouring digestive enzymes onto their prey, they can transform it from solid form to liquified slurry.
Not only does this make feeding physically easier, but it also removes components that can't be used by the spider. What's left behind is essentially a perfectly formulated energy drink which the spider slurps up.
Just how often South American tarantulas feed on snakes remains something of a mystery, but Borges and the team believe it to be quite rare. "It is very gratifying to contribute to this record," he told National Geographic. "As far as we know, there are only cases documented from situations in captivity."
Top header image: kyhLiang/Flickr