Video: World's rarest gorilla caught on tape (CBS) Conservationists in Cameroon have captured the best video footage to date of the world's rarest gorilla. Researchers say they have gone years - even decades - without catching a glimpse of the critically endangered Cross River gorilla, a sub-species with just 250 individuals left on Earth. But conservationists in the Kagwene Gorilla Sanctuary used four "camera traps," which are activated by motion sensors to gather nearly two minutes of footage showing a group of Cross River gorillas moving along a forest path. The video includes a male silverback making a chest-beating display in front of the camera, which produces an unexpected popping sound. Another of the gorillas appears to be missing a hand - an indicator, experts say, of snares in the gorillas' range. Patrolling of the protected area has increased since the now-healed injury likely occurred. The footage was provided by the Wildlife Conservation Society, which conducts conservation projects and education to protect wildlife and wildlife habitats worldwide. The WCS also manages the world's largest system of urban wildlife parks, including its flagship, the Bronx Zoo in New York. Donations that support wildlife conservations projects can be made through the Wildlife Conservation Society's website.