National Geographic: Long thought to be extinct, one of the world’s rarest primates has been caught on camera for the first time, scientists announced Monday. Discovered in 1937 but "missing" for 60 years, Sri Lanka’s Horton Plains slender loris was presumed to have died out. In 2002 a fleeting nighttime sighting of something looking like the elusive tree-dweller, however, gave conservationists hope. Follow-up surveys led by the Zoological Society of London finally confirmed the lorises are …