Spies, herders, painters: the many unusual roles of drones

Drones are proven for surveillance or delivery, but what's less widely known is their usefulness for herding elephants and seeing through walls.

Quick take: Businesses and non-profits are finding innovative ways to use drones to accomplish tasks that humans cannot do, and these developments have yielded benefits for environmental conservation, military strategy and more.

• Conservation Drones is equipping Nepal and parts of Africa with low-cost aircraft that spot elephant poachers in the forest. (Scientific American)
• Drones in Hawaii have found rare plant species by flying to precarious spots like steep cliffs. (The Verge)
• Researchers at the University of California in Santa Barbara have developed drones that see through walls, making them expert spies. As two drones navigate a closed structure, one emits a Wi-Fi signal, and the other picks it up. Together, they build a 3D image of the interior. (TechCrunch)
• Drones found a till-then undiscovered ancient monument in Petra. It's the size of an Olympic swimming pool. (National Geographic)
• Drones are herding elephants away from crops during harvest time in Tanzania. The pachyderms retreat when they spot the unmanned aircraft. (New Atlas)
• An Italian project, "Paint By Drone," uses the aircraft to produce murals and designs on massive vertical surfaces. (CityLab)
• In Australia, an engineer is developing drones that release germinated seeds to replace forests. She predicts the drones will be able to plant a billion trees a year to combat the climate effects of deforestation. (Australian Broadcasting Company)