This is the dramatic moment a sleepy Hippopotamus reversed the rules of nature by viciously attacking a lioness.

The clip taken by tourists on the Maasai Mara National Reserve in southwestern Kenya, along the Tanzanian border, starts with the large lioness traversing the overgrown savannah in search for food.

After around a minute of scouring the vast open plains it stumbles across the sleeping hippo and then approaches stealthily, thinking it had found a large snack.

Wrong: The lioness goes to pounce on the Hippopotamus in the Maasai Mara National Reserve

Attack: The hippo shoots up to chase off the fleeing cat

Grab: In a shock move the hippo engulfs the lioness’ head in its mouth and slings it to the ground

However, the feline came up to the rear of the hippo, perhaps erroneously, and instead of sinking its teeth into its neck the lioness sniffs its behind confused.

At this point the grunting hippo shoots up and runs at the now fleeing lioness.

But the big cat underestimates the herbivore’s speed.