Watch: Why you should never turn your back to a lion, even in a zoo

You must have seen it happen very often with a house cat. In moments of play, a tiny tabby pounces on an imaginary object or a ball of wool. The internet is littered with videos like these, sending everyone into raptures.

The video above is also of a cat at play. Not an ordinary one, mind you, but a hulking 185-kg king of the jungle. In a zoo in Chiba, Japan, a two-year-old boy stands and looks into the lion enclosure from the comfortable safety beyond the glass wall. Then he turns and looks away.

And at that moment, the lion comes running towards the young boy, paws outstretched, only to be stopped by the glass barricade separating the two worlds.

Animal rights experts have cited the incident as an example of why zoos are not an ideal environment for animals, especially predators like lions. Lion expert Adam M Roberts from Born Free USA told The Dodo: "Lions are natural wild predators and the child in this video, especially when turning his back to the massive feline, becomes prey in the animal's eyes. The firm glass wall held the lion inside his enclosure, surely frustrating his innate instincts."

However, the zoo authorities have said that the big cat only wanted to play with the kid and often reacts in a similar fashion when children visit the zoo.

Below, lions can be seen in a more amicable temperament as "Lion Whisperer" Kevin Richardson visits some of his lion friends. He could quite possible be the luckiest man on earth as the lions allow him to play, cuddle and rest on their backs. Of course, the lions don't understand their own strength and often end up scratching him and hurting him, but never, according to Richardson, with the intention to attack him.