They might be small, but spiders and their creepy-crawly cousins are fierce predators. In the depths of Peru’s Amazon rainforest, invertebrates like tarantulas and centipedes aren’t just nibbling bugs—they’re taking down vertebrates. And in a now-famous scene, one even took on an opossum.
Biologists captured fifteen examples of invertebrates preying on vertebrates—everything from tadpoles and lizards to snakes and, in one jaw-dropping moment, a mouse-sized marsupial. That last one? A world first.
The rainforest’s eight-legged hunters
Most of these nighttime encounters took place in Peru’s lowland rainforests, home to some of the world’s most biodiverse ecosystems. As night falls, these forests buzz with movement—and eight-legged predators take center stage. Wandering spiders from the Ctenidae family are everywhere: on leaves, branches, and the forest floor.
A fishing spider, or dolomedes, snatches a tadpole from a pond deep in the Peruvian rainforest.
“During our night surveys, we often see spiders carrying prey,” explained biologist Rudolf von May. “Usually it’s insects like crickets or moths. But sometimes, it’s a frog or even a lizard.”
On two occasions, the team also recovered dead snakes—one a venomous coral snake—taken down by centipedes.
But the most astonishing moment came when researchers spotted a tarantula the size of a dinner plate attacking a mouse opossum.
“It was still wriggling when we found them,” said Michael Grundler, a doctoral student on the team. “Then after about 30 seconds, it went completely limp. We were shocked. We couldn’t believe what we were witnessing.”
Later, a mammal expert at the American Museum of Natural History confirmed it: these were the first-ever images of a tarantula hunting and consuming an opossum.
Tarantula expert Rick West, who wasn’t part of the study, wasn’t surprised. “While rare, tarantulas do prey on vertebrates,” he said. “They’re opportunistic—they’ll take down anything they can subdue.”
An unlikely roommate
Predation wasn’t the only surprise. The team also confirmed something even more curious—a mutualistic relationship between a tarantula and one special frog.
While most frogs would be fair game for a hungry spider, the species Chiasmocleis ventrimaculata seems to get a pass. In fact, it shares the tarantula’s burrow.
“We don’t know why the spider doesn’t eat this frog,” von May said. “Out of the hundreds of frog species in the Amazon, this one seems to have figured out how to live with a predator.”
Scientists think the frog might repay its host by feeding on parasitic insects, acting as a live-in pest control.
“It’s a nice reminder,” said von May, “that not everything in the rainforest is out to kill. Sometimes, it’s about survival through cooperation.”
A tangle of life and death in the Amazon
The research site in Peru is teeming with life—85 amphibian species and 90 reptile species call it home. And when you factor in the rainforest’s vast array of invertebrates, the potential predator-prey interactions skyrocket.
“This kind of natural history research is key to understanding how rainforest ecosystems function,” von May concluded.
