Thermal camera image of hippos (Hippopotamus amphibius), crocodile (Crocodylus niloticus) and wildebeest (Connochaetes taurinus, far left) on the banks of the Mara River, Masai Mara, Kenya. Image taken with no artificial light, on location for National Geographic Nightstalkers film. *THIS IMAGE CAN ONLY BE USED IF NATIONAL GEOGRAPHIC NIGHTSTALKERS IS REFERENCED*