DODOMA, Tanzania, June 9 (UPI) -- In 2010, ecologist Alexandra Swanson and her colleagues placed some 225 cameras in remote locations across the Serengeti National Park -- some mounted on steel poles staked into the ground, others affixed to trees.
Several years later, those cameras continue to pay remarkable dividends in the form of wildlife documentation. Recently, Swanson's research team decided to go public with their trove of animal photos -- captivating shots of hippos, hyenas, buffalos, lions, elephants, impalas, giraffes and more.
But the scientists couldn't simply unleash all 1.2 million photographs onto the Internet. First, the animals had to be identified and the photos organized. To do so, researchers recruited volunteers through a citizen science web portal called Zooniverse.
Some 28,000 volunteers from over 70 countries scanned photos and voted on the species classification of the pictured animal. Each photo was reviewed by an average of 15 people, with the most-voted species getting the official nod.
Researchers tried to make the process as user friendly as possible.
"We also have a 'looks like' filter. If, say, the person has no idea what it is but thinks it looks like an antelope, they can filter the list to what looks like an antelope," Margaret Kosmala, one of Swanson's collaborators, told Wired. "There are also filters based on coat patterns, colors, whether you can see spots or bands or stripes of colors. You're also able to look at different views and angles of animals."
The classification effort was double-checked by experts. Roughly 4,000 of the reviewed photos were given to experienced biologists. Their review showed that the volunteers accurately identified the photographed animal more than 96 percent of the time.
Identifying the animals turned out to be a relatively simple problem. Keeping cameras in working order is more difficult, researchers say. Each year, scientists have to replace roughly a quarter of the cameras.
"The herbivores will rub up against them, but the hyenas will just chew through them," Swanson, a postdoctoral fellow at Oxford, told BBC News. "And then the elephants rip the cameras off their mounts and throw them across the ground. Sometimes I'd get to a camera position and find bits of plastic strewn all around."
Swanson -- who was earning her PhD with the University of Minnesota when she began the project -- and her colleagues are using the photos to keep better stock of the park's wildlife populations and to understand how animals use, share and divide habitat.