One of the rarest and most threatened mammals on earth has been caught on camera in Vietnam for the first time in 15 years, renewing hope for the recovery of the species, an international conservation group said Wednesday. The Saola, a long-horned ox, was photographed by a camera in a forest in central Vietnam in September, the WWF said in a statement Wednesday. "This is a breathtaking discovery and renews hope for the recovery of the species," Van Ngoc Thinh, WWF - Vietnam's country director, was quoted as saying.