Watch as this cuttlefish catches its prey with its tentacle harpoons. To a scuba diver, tropical coral reefs are the picture of colourful, light-dappled tranquillity. To the scaly and gilled inhabitants, it’s a fish-eat-fish environment ruled by pods of dolphins who prowl the area at mealtimes while everyone else runs for cover. Watch Coastal Odyssey on Wednesdays at 7-9pm on National Geographic WILD UK. | National Geographic UK

Each year, nearly two million wildebeest and zebra cross the Serengeti on a quest for fresh grazing. But two legendary rivers stand in their way, the Grumeti and the Mara, each ruled by a formidable dynasty of Nile crocodiles. For this zebra, the instinct to drink is overpowering, and they attempt to cross, alone. Unfortunately for this zebra, that was the wrong choice. In the deep, fast waters of the Mara, privilege reigns, kills come easy, and food is plentiful. Watch Croc Wars Grumeti vs Mara