We all know cheetahs are the fastest land animals on the planet, but dedicated scientists are continuing to discover much more about the habits of these and other big cats.

Professor Alan Wilson has developed a hi-tech collar and has been tracking three cheetahs for five years – and what he’s discovering is groundbreaking.

We also meet Dr Natalia Borrego, who is studying the intelligence of lions.

There’s a beautiful scene with conservationist Kevin Richardson as a lioness greets and licks him as affectionately as a domestic cat.

It’s a fabulous insight into humanity’s work with wild animals and, thanks to their efforts, many species are coming back from the brink of extinction.

Please note this programme doesn’t air in Wales.