The encounter, which was captured on video, showed that spiders in the Amazon are more than the little critters that spin silk webs across tree branches and storm ant hills to get their meals.
Researchers say that in these lowland rain forests along the Madre de Dios River, spiders are the wolves in a much larger ecosystem — prowling around at night and hunting prey that, in many other places, would be the predators hunting them.
Evolutionary biologist Dan Rabosky told The Washington Post that people may not consider spiders a main predator to reptiles, amphibians and small mammals, but in the Amazon “it’s a very open question about what is the major predator on those things."
"My money would be on the spiders,” he added.
Rabosky, an associate professor in the department of ecology and evolutionary biology at the University of Michigan, published a paper along with his team of researchers late last month in the peer-reviewed journal Amphibian & Reptile Conservation. The paper detailed the team’s observed interactions in the Amazon over the past several years between small vertebrates and arthropods.
Including a tarantula preying on a mouse opossum.
Rabosky’s team, which includes postdoctoral, graduate and undergraduate students from the University of Michigan as well as Peruvian researchers, has been visiting the Amazon once or twice per year to better understand why there are so many species of reptiles and amphibians in the rain forest, he said. During those trips, the researchers have seen numerous rare encounters, which they have detailed in the paper, titled “Ecological interactions between arthropods and small vertebrates in a lowland Amazon rain forest.”
From 2008 to 2017, the researchers observed spiders preying various species that, in some habitats, could easily be feeding on them — various frogs, a lizard and, of course, a mouse opossum.
One night in November 2016, several researchers were on a night survey when they spotted a tarantula — described as the size of a dinner plate — dragging away a gray-and-white marsupial.
Michael Grundler, a doctoral candidate, told the University of Michigan News that he and two others were working when they heard “some scrabbling in the leaf litter.”
“We looked over and we saw a large tarantula on top of an opossum,” he said in a statement. He said his sister, Maggie, who was also on the research team, pulled out her camera and started filming.
Grundler said it “already been grasped by the tarantula and was still struggling weakly at that point, but after about 30 seconds it stopped kicking.”
Grundler said in the statement that, at the time, he and the other researchers were “pretty ecstatic and shocked, and we couldn’t really believe what we were seeing.” The researcher noted that later on, an opossum expert at the American Museum of Natural History told them that they were the first to document a mygalomorph, a class that includes tarantulas, preying on an opossum.
As for the searing image of a giant spider carting off a cute, furry critter, Rabosky, who leads the research team, said it’s not as scary as it may seem.
“Our biases lead us to think this is a scarier predation than anything else out there,” he said. “In reality, we fear animals like spiders because they just seem so different to us — they really pose no danger, and they are super important parts of their ecosystems. Walking on the African savanna at night with lions about is much scarier!”