Camera traps (and a bit of luck) reveal the first-ever footage of this elusive rodent.
When biologist Diego Mosquera captured the first-ever photographs of a living dark tree rat (Echimys saturnus) several years ago in Ecuador, it was more of a pleasant surprise than a planned event.
"Those records were obtained, let's say, randomly. We were focusing our study on different saltlicks, primarily looking at large mammals and ground birds, and the dark tree rat happened to show up on our cameras a few times over a period of four years," Mosquera told me over email.
And now, it seems the scientist's patience (and a little bit of luck) has paid off again. Mosquera and three colleagues succeeded in capturing the world's only video footage of the dark tree rat in eastern Ecuador's Tiputini Biodiversity Station. Their findings were recently published in the Sociedad Argentina para el Estudio de los Mamíferos journal, Mastozoología Neotropical.
So little is understood about this elusive rodent, which is part of the Echimys or "spiny rat" genus, that its official threat status, according to the International Union for Conservation of Nature, is simply "data deficient." And while it's easily recognizable—what with its magnificent, white "fully-furred" tail—scientists have been left in the dark regarding other characteristics like its behavior, range, and diet. Until now, experts weren't even sure whether the animal was an herbivore or omnivore. Current descriptions of the species are based off observations of fewer than 10 individuals.
Biologists who study wildlife in South America's dense rainforests know that the dark tree rat is both nocturnal and arboreal. And because of these two traits, Mosquera said, they're incredibly difficult to see or capture. All of the species belonging to Echimys tend to hang out in the upper and middle levels of the forest, which makes accessing their habitat nearly impossible for scientists without the aid of tools like camera traps.
"Because we used video, we were able to obtain more information than with traditional still pictures, and since virtually nothing is known about this species, everything seemed to be new information," Mosquera added.
"We knew that dark tree rats were nocturnal and we confirmed that. We noticed, however, that they were more active on saltlicks relatively early at night. Also, the fact that they visited a saltlick systematically suggests an herbivore diet—if they eat leaves, they might need to consume clay on a regular basis to help their bodies to destroy secondary compounds and get extra minerals. Although, the use of a particular site could be related to other factors, like accessibility. And since these are the first videos ever recorded for this species, I was simply fascinated with the way the look and move!"
Nestled in Ecuador's Orellana Province, the Tiputini Biodiversity Station has some of the greatest diversity of flora and fauna on Earth. It features a wide array of habitats, including terra firme ("solid ground") and várzea (seasonal floodplain) forests, palm swamps, and wetlands. When the team of scientists installed their camera traps in an old-growth forest just north of the Tiputini River, they were treated to periodic visits from a host of other species including red howler monkeys (Alouatta seniculus), white-bellied spider monkeys (Ateles belzebuth), a two-toed sloth (Choloepus didactylus), and a bicolored porcupine (Coendou bicolor).
Over the last couple of decades, conservation biologists have enthusiastically embraced the use of camera traps and motion detectors. All over the globe, researchers are deploying regular cameras with infrared triggers to gather crucial data about rare and elusive species that occupy remote or hard-to-reach areas.
"It's pretty rare that I'm working on a project where I never see the animals I'm photographing," wildlife photographer Will Burrard-Lucas once told the New York Times. But "to take these beautiful photographs, a camera trap was literally the only way that would be possible."
In some cases, biologists have managed to amass so many photos, they're now calling on citizen scientists to assist with identifying all of the species caught on camera. Databases such as Snapshot Serengeti utilize crowdsourcing to classify the hundreds of different animals documented over "millions" of images.
Mosquera agrees that camera traps have helped to revolutionize data collection, and can often make field research less invasive and more accessible to the general public.
"I think we can certainly divide the study of wildlife on 'before' and 'after' camera traps. These days that you practically wouldn't think of doing anything without them," he told me. "Ten or twelve years ago, digital camera traps didn't even exist, and now you have many options to choose from!"
As for the little dark tree rat, further studies are needed to fully assess its conservation status. As with other wildlife native to the Amazon, the species faces threats from rapid deforestation and habitat fragmentation stemming from agriculture, mining, and oil extraction.
For now, at the very least, people everywhere can marvel at a creature that would otherwise remain hidden from the outside world.