Fernando Constantino Martínez Belmar's Image

Fernando Constantino Martínez Belmar (Mexico) waits in darkness as a Yucatan rat snake snaps up a bat.

Using a red light, which both bats and snakes are less sensitive to, Fernando kept his eye on the Yucatán rat snake poking out of a crack. He had just seconds to get the shot as the rat snake pounced snatching a bat out of mid-air before retreating into its crevice with its prey.

Every evening at sundown in the Cave of the Hanging Snakes thousands of bats leave for the night, heading out in search of food. But it's not just the bats that are on the move, hungry rat snakes emerge from their crevices to dangle from the cave roof, ready to snatch the bats as they pass in and out. With such a mass exodus, the rat snakes have a good chance of catching one.

Neither predator nor prey can see each other, but they do have ways to locate each other in the darkness. The bats can pinpoint the rat snakes by using echolocation and the snakes can feel the movement of the bats as they fly past. Rat snakes are not venomous, instead they kill their prey by swallowing them whole. Alongside bats, they will typically hunt small rodents, birds, frogs and lizards.

Sugandhi Gadadhar, wildlife filmmaker and judge said, 'What made the image for me is the timing - the speed and alertness of the snake, the bat with its mouth left open and both predator and prey half-hung in air'.