You could call it one of the world's longest games of hide and seek. For more than 20 years, the Ili pika (Ochotona iliensis), a type of tiny, mountain-dwelling mammal with a teddy bear face, had eluded scientists in the Tianshan Mountains (map) of northwestern China. People have seen the furry critter only a handful of times since it was discovered by accident in 1983. In fact, people have spotted only 29 live individuals, and little is known about the animal's ecology and behavior. Then, in summer 2014, researchers rediscovered the pika. Weidong Li, the species' original discoverer and a scientist at the Xinjiang Institute for Ecology and Geography, had gathered a group of volunteers in the Tianshan Mountains for some pika searching. At noon one day, as they were setting up camera traps, the team spotted their prize. A curious pika emerged from a gap in the cliff face, and Li snapped a few photos. (Source: National Geographic)