Spiders around the world are capable of ensnaring and devouring snakes many times their size, reports Jason Bittel for National Geographic.
The behavior is rare, but not as rare as one would think—a study published in May in the Journal of Arachnology says there are at least 40 species of spiders from 11 families that are known to feast on serpents. As for the snakes getting caught on the wrong end of this ecological equation, the scaly victims hailed from more than 90 different species.
“I was surprised that snake-eating by spiders can be found on all continents (except Antarctica),” study author Martin Nyffeler, a spider researcher at the University of Basel in Switzerland, tells National Geographic. “I was surprised that so many different spider groups are capable of killing and eating snakes. I was surprised that so many different snake species are occasionally killed by spiders.”
Consider the Australian redback spider, also known as the Australian black widow: Females of this highly venomous species are less than a half-inch long, yet they are known to kill and eat young eastern brown snakes, themselves one of the most venomous snakes in the world. Per Asher Jones for Science News, the redback traps snakes using its crisscrossing, disorganized-looking web of sticky silk and then rushes in to inject its deadly venom.
As in many spiders, the venom also starts the process of digesting the snake’s insides, which the spider then sucks out. But for a large meal as large as a snake, the spider might need days or even weeks to finish eating, according to National Geographic.
“For most people in the world, this would be their worst nightmare. Eight legs against zero legs,” Emily Taylor, a snake biologist at California Polytechnic State University who was not involved in the study, tells National Geographic. “But for me, this is like my wonderland.”
Members of the so-called widow family of spiders—especially the Australian redback, the African button spider, Israeli and Iranian widow spiders as well as four North American species—are the most prolific snake-killers, comprising about half of the study’s documented cases, reports Jennifer Ouellette for Ars Technica. Tarantulas and orb-weaving spiders were the second and third most common snake hunting families, respectively. While the widows and the orb-weavers both use webs to catch snakes, the tarantulas actually stalk their prey on the ground, eventually pouncing and hanging onto the thrashing snake for dear life until their venom takes effect.
To compile their list of cold-blooded killers, Nyffeler and his co-authors scoured research journals, magazines and even social media, such as YouTube, for reports of spiders eating snakes, according to Science News. Their search yielded 319 such instances, most of which came from Australia and the United States, but spanned every continent except Antarctica.
“I didn’t realize how common this was. I don’t think anybody did,” Mercedes Burns, an evolutionary biologist at the University of Maryland who was not involved in the research, tells Science News. “I was kind of surprised at the types of snakes that were described because some of them are pretty big, pretty strong.”
Identifying a host of spiders with venom that clearly works on vertebrates could identify new targets for research aimed at discovering the chemical components that do the toxins’ deadly work.
Nyffeler tells Science News he hopes his research makes people appreciate spiders a bit more. “The fact that small spiders are capable of killing much larger snakes is very fascinating,” he says. “Knowing and understanding this enriches our understanding of how nature works.”