Muntiacus rooseveltorum, also known as Roosevelt's muntjacs or Roosevelt's barking deer -- a rare species first discovered by the sons of President Teddy Roosevelt in Laos -- hadn't been observed alive anywhere since 1929. But recent camera-trap images in Vietnam's Xuan Lien Nature Reserve show the species is prancing through pockets of deep forest, according to a release of Vietnam's Ministry of Natural Resources and Environment. A team of researchers from the Center for Natural Resources and Environment Studies at Vietnam National University compiled evidence, including horn and skin samples, to confirm what the photographs suggested. "Given the rarity of this species and the escalating hunting and habitat loss in the region, it is important to conduct field research to assess its population status," the researchers wrote in a recent paper on the rediscovery -- published last month in Conservation Genetics. "Such information is critically needed to design a conservation plan for this highly elusive and threatened taxon." Roosevelt's sons, Theodore, Jr. and Kermit, first discovered the species on an expedition to Southeast Asia with Harold Jefferson Coolidge, Jr., a famous zoologist who later became head of both the International Union for Conservation of Nature and the World Wildlife Fund. Skepticism of the discovery persisted, due to the lack of evidence, but in 1999 DNA tests of several muntjac skulls confirmed the separate species' unique genetics.