If you're looking for real-life nightmares to keep you up at night, the University of Michigan has got you covered. 

A University of Michigan-led team of biologists has documented 15 rare and disturbing predator-prey interactions in the Amazon rainforest including images of a dinner-plate-size tarantula dragging a young opossum across the forest floor.

The images were captured during their annual month-long expedition through southern Peru. The team trekked in the most bio-diverse ecosystem on the planet, said leader Dan Rabosky, associate professor of Ecology and Evolutionary Biology at U-M. 

“This is an underappreciated source of mortality among vertebrates,” Rabosky said. “A surprising amount of death of small vertebrates in the Amazon is likely due to arthropods such as big spiders and centipedes.”

The photos are part of a new journal article “Ecological interactions between arthropods and small vertebrates in a lowland Amazon rainforest.” Arthropods are invertebrate animals with segmented bodies and jointed appendages that include insects, arachnids (spiders, scorpions, mites and ticks) and crustaceans, according to the university.

The article, published online Feb. 28 in Amphibian & Reptile Conservation, details instances of arthropod predators—mostly large spiders along with a few centipedes and a giant water bug—preying on vertebrates such as frogs and tadpoles, lizards, snakes, and even a small opossum.

This video shows the researches on location in Peru:

The team’s main research focus is the ecology of reptiles and amphibians. But over the years, scientists have documented numerous interactions between arthropod predators and vertebrate prey.

“We kept recording these events, and at some point we realized that we had enough observations to put them together in a paper,” said Rabosky, also an associate curator at the U-M Museum of Zoology.

Nearly all of the sightings were made at night when the arthropod predators are most active, team members said. At night, they walked slowly through the forest with flashlights and headlamps, in single file, scanning the forest. 

One night, U-M doctoral candidate Michael Grundler and two other students “heard some scrabbling in the leaf litter.”

“We looked over and we saw a large tarantula on top of an opossum,” said Grundler, a co-author of the paper. “The opossum had already been grasped by the tarantula and was still struggling weakly at that point, but after about 30 seconds it stopped kicking.”

The tarantula was the size of a dinner plate, and the mouse opossum was about the size of a softball. 

Later, an opossum expert at the American Museum of Natural History confirmed they had captured the first documentation of a large mygalomorph spider preying on an opossum. The infraorder Mygalomorphae is a group of mostly heavy-bodied, stout-legged spiders that includes tarantulas.

“We were pretty ecstatic and shocked, and we couldn’t really believe what we were seeing,” Michael Grundler said. “We knew we were witnessing something pretty special, but we weren’t aware that it was the first observation until after the fact.”
Twitter: @SarahRahal_

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