A typical spider dinner menu might include insects, worms, or even small lizards and frogs. But some arachnids have more adventurous tastes. A surprising new study has found that spiders can immobilize and then eat snakes up to 30 times their size.
Get the Australian redback. Excluding the legs, a female of this spider species is the size of an M&M candy, but can take down large prey, such as the eastern brown snake, which is in fact one of the most venomous snakes in the world.
The spider’s web is a messy tangle of silk whose long sticky threads dangle to the ground, and a snake that accidentally slips into this trap could get stuck. The redback quickly throws more sticky silk to subdue his victim in distress, and finally, chew!
Its bite releases a powerful toxin which eventually kills the snake. “I find it interesting that small Australian red spiders can kill brown snakes”says Martin Nyffeler “It’s very charming and a bit scary!“, Nyffeler is a zoologist specializing in spider biology and works at the University of Basel in Switzerland.
But the redbacks they are far from the only spiders with an appetite for snakes. Nyffeler collaborated with Whit Gibbons at the University of Georgia in Athens to study snake-eating spiders.
The two searched for reports about it in all sorts of places, from research journals and magazine articles to social media and YouTube videos. In all, they analyzed 319 accounts. Most came from Australia and the United States. But these spiders live on all continents except Antarctica, which surprised them.
Mercedes Burns is an evolutionary biologist. Study arachnids at the University of Maryland, Baltimore County. “I didn’t realize how common it was”, He says, “I don’t think anyone has ever done that.”
Nyffeler and Gibbons have now shared their findings in April on The Journal of Arachnology, now we know that a wide range of spiders have a serpentine diet. They found that at least 11 different spider families feed on snakes.
The best snake hunters are tangle spiders, named after messy webs built close to the ground. This group includes North American and redback widow spiders. Relatively small, these spiders can catch snakes from 10 to 30 times larger than their size, says Nyffeler.
The neater ball-weaving spiders create organized spider webs in the shape of a wheel. They look like the ones seen on Halloween decorations. One member of this group, a golden silk ball weaver in Florida, caught the longest snake in the study: a 1-meter green snake.
“Spider silk is an extraordinary biomaterial”says Burns. It can catch and hold things that are strong and can fly. They can also capture muscular prey, such as a snake. “It’s pretty awesome”, He says.
Spiders like tarantulas have a different tactic for catching snakes. They actively hunt their prey, then use powerful jaws called chelicerae to release a powerful venom.
“Often a tarantula tries to grab the snake by the head and resists despite all the efforts of the snake to shake off”, says Nyffeler. Once the venom takes effect, the snake calms down.
In some meetings, he and Gibbons have learned, that the venom can defeat snakes in minutes. Some spiders, on the other hand, took days to kill their prey. “I was a little surprised by the types of snakes described because some of them are quite large, quite strong”says Burns. The snakes came from seven different families. Some were highly poisonous. These include coral snakes, rattles, palm vipers, and lanceheads.