Planet Earth's fourth episode of the second series aired last night and there were plenty of highlights, but one of the best has to be a dramatic chase in the Namib desert starring a determined pride of lions and an even-more determined giraffe.

After that now-famous footage of an iguana out-running dozens of racer snakes in the Galapagos islands and shocking footage of a jaguar getting its jaws around a caiman, viewers were wondering how episode four of the BBC documentary would compare.

Sunday night's show offered a look at one of the most extreme environments on Earth as a pride of lions desperately tried to find food in an area the size of Switzerland.

Attempting to take down a giraffe by forcing it into a trap ended in failure as the lead lioness was thrown to the ground and then dealt a nasty kick to the head for good measure as the giraffe ran to safety.

Also in this episode was a shoot that involved the team driving hundreds of miles trying to track down a huge swarm of locusts.

(BBC (BBC)

Using a helicopter, they managed to capture rare footage of a plague of several billion locusts flying through the air.

Researcher Toby Nowland told The Mirror: "The sound was incredible and so unexpected – the sound of a billion locust wings clattering - a gentle roar that built and eventually sounded like a giant wave pushing overhead.