Actually declaring a species extinct is a long and laborious process that requires evidence beyond a reasonable doubt the plant or animal has disappeared from the face of the earth. The difficulty of this process is highlighted by the fact that only 875 extinctions have been officially documented since 1500. A few of those 875 have made miraculous reappearances.
1. Sierra Nevada Red Fox: One such species was the Sierra Nevada red fox. It was thought extinct until U.S. Forest Service biologists captured photos of the fox with a camera trap in 2010. Researchers also took DNA samples of saliva pulled from a bait bag the fox bit into to experts at the University of California, Davis. Lab tests proved that the Sierra Nevada red fox was back.
2. Giant Palouse Earthworm
3. Horton Plains Slender Loris: After it had disappeared from 1939 to 2002, conservationists thought this little mammal was extinct. But the Horton Plains slender loris, photographed for the first time in 2010 by the Zoological Society of London’s EDGE project, had indeed survived. There have only been four documented sightings of the small, reclusive primate since 1937.
4. Ghost Orchid: The ghost orchid, a rare plant named for its almost transparent flowers and habit of hiding underground for years, has been found again in the UK after being declared extinct there in 2005. The small flower does not rely on photosynthesis for sustenance and instead lives in symbiosis with an underground fungus that supplies nutrients. This allows the plant to survive underground for years without blooming.
5. Black Kokanee Salmon: In 1940, a hydroelectric dam was constructed in northern Akita Prefecture, Japan. The project, it was known at the time, would destroy the only native habitat of the black kokanee salmon by making the waters too acidic for the fish to survive. Still, developers went ahead with their plans. 70 years later, a small population of the extremely rare fish was discovered in nearby Saiko Lake.
6. Gray Whale
7. Yellow Spotted Bell Frog
8. Short Tailed Albatross: In just a few short decades, the short tailed albatross declined from a population of millions, at the beginning of the 20th century, to suspected extinction in the 1940s. Years later, small nesting populations were found on remote islands in the Pacific.
9. Rosser’s Sac Spider