Speculation abounds as to the meaning behind the human obsession with taking selfies. But what about animals? They take selfies too, albeit unknowingly and without a stick to aid them. But when a wild animal walks in front of a motion-activated camera, otherwise known as a camera trap, it reveals more than the average selfie.

A recent study compiled some 2.5 million of these "selfies" taken by over 1,000 hidden camera traps scattered throughout global tropics in an effort to better understand animal diversity and behavior. In analyzing photos of 244 species from 15 protected tropical forests over the last 3-8 years, researchers found that species distribution and number had not significantly declined. In an of era rapid human population growth with fewer and fewer havens for wild animals, this general stability was unexpected.

Dr. Lydia Beaudrot, an ecologist, conservation biologist and lead author of the study, told me over email that they were surprised to find that over the time span studied "protected areas are supporting stable communities of tropical mammals and birds."

"There was a lot of variability in how individual populations were doing—some were increasing, others were decreasing—but on the whole, there was community level stability," she said.

The researchers—who are all part of the Tropical Ecology Assessment and Monitoring (TEAM) Network—assert that the data suggests there has been "less extreme deterioration in tropical forest protected areas" than many "aggregated secondary data and expert opinions" might suggest.

According to Jorge Ahumada, executive director of the TEAM Network and a study co-author, this is the first time that primary data has been collected in such a standardized way as to be able to draw this type of conclusion.

"With this data, we have created a public resource that can be used by governments or others in the conservation community to inform decisions," Ahumada said in a statement.

Beaudrot echoed this sentiment, saying that with the hidden infrastructure in place, it's possible to "evaluate the success of conservation interventions, such as increased park patrols."

In the Tropics

The authors note that species loss is especially high in tropical regions of the globe where most of the world's biodiversity is and where threats from environmental degradation and climate change are often the most severe. While protected areas are viewed as critical for ecosystem stability, their actual value in preserving many animal populations is not consistently known. In monitoring understudied areas of some of these forests with motion-activated camera traps, the researchers were able to offer a firsthand account of the situation that was previously available.

What the team of scientists conducting the study did find was that occupancy declined in 22%, increased in 17%, and exhibited no change in 22% of populations during the last 3–8 years, while 39% of populations were detected too infrequently to assess occupancy changes.

Much of the rapid rate of land conversion in tropical regions can be attributed to high population growth rates and natural-resource based economies that involve mining, clear-cutting and other harmful practices, according to the study. As a result "defaunation"—animal losses ranging from local population decline to species extinction—is most extreme in these areas. The authors state that the loss of tropical mammals and birds could lead to a cascading effect in which the deterioration of forest ecosystems creates a biodiversity crisis.

In many ways this crisis is already far underway, as a number of scientists believe the planet has already entered its sixth mass extinction. According to a recent report in Science, more than 75% of species of animals and plants could be gone within a few centuries. While it's a relief that obvious or overwhelming loss of species in the animal selfies is not apparent, there are plenty of reasons to doubt that biodiversity will continue to thrive as well in these regions. Three to eight years may seem like an extended period in modern human society, but in ecological terms its just a brief notch in a timeline that's increasingly dominated by humans.

The Bigger Picture

Beaudrot told me that camera traps are being used more and more to monitor wildlife because they are cost effective and can gather information on species that are otherwise challenging to detect. Furthermore, the process is relatively unobtrusive and doesn't require altering habitat in order to observe it. In especially hard-to-reach regions, eco-drones are even being used to monitor wildlife.

The photos from camera traps offer scientists a behind-the-scenes look at the lives of wild animals in their natural setting, and in their natural behavior. This can help biologists and conservationists better understand how animals utilize habitat, socialize with each other and even what they eat.

While many of the photos from these cameras are grainy and out of focus, there is a growing movement to use higher quality cameras, such as DSLRs, to create stunning images that are both artistic and informative.