Frances Grant: Nature stuns in all its glory

Note to self: never swim with the seals off the Cape of South Africa during the summer breeding season. As we saw, in last night's lavishly filmed Planet Earth (Prime, 8.35pm), the ocean's most fearsome predators, great white sharks, treat the seal colonies like a bag of party mix.

They dip in, pick out some juicy-looking seals and toss them into their great maws with a fancy aerial flip to complete the act. The seals' only advantage when being pursued by these beasts is their cornering ability. It's not much of an advantage.

Planet Earth is the year's big natural history number. Made by the Beeb, it is its most ambitious and expensive factual series. The series is narrated, of course, by David Attenborough, who goes with BBC nature documentary series like polar bears go with ice caps.

The five-parter is made by the team who brought us the oceanic spectacular, The Blue Planet and, if last night's opening episode was anything to go by, we can expect footage every bit as stunning.

The programme was as compelling as it was a reminder that, while there may be 6 billion of us, and yes, we're a worry when it comes to looking after our lovely home in space, there are still tracts of wilderness where nature is definitely red in tooth and claw.

The series is filmed in high definition, all the better to see that pack of wolves closing in on the migrating caribou, or those African hunting dogs pack down on a poor impala. The secret of their predatory success, we learned, was team work. Remind your boss of this next time team work is an issue.

Last night's episode was headed "From Pole to Pole" and the theme was the seasons, beginning with film of a polar bear and her two cubs emerging in the Arctic spring, then moving through warmer latitudes to the tropics.

The episode could also have been called the world's most amazing overland migrations, as the cameras followed caribou which wander thousands of kilometres across northern Canada, and the great migrations of beasts across Africa to the Okavango Delta.

Highlight of the night: extraordinary underwater footage of ecstatic elephants taking the weight off with some aqua-jogging in the Delta after a searing and exhausting trek through the dust storms of the Kalahari. Sure beats watching a ballroom-dancing Rodney Hide.

The seasonal theme seemed mostly an excuse to link footage from around the globe and it took a while for the script to catch up and let us know where we were at times. And, while Attenborough is as authoritative as ever, he can't disguise the fact that the script is Nature 101, explaining, for example, that the seasons are caused by the Earth's tilt on its axis.

But the pictures are the point, and with £16 million and four years spent on making Planet Earth, extraordinary sights are guaranteed.

Some scenes are heart-stoppingly brutal, such as the feasting frolics of the great whites, but the main message is conservation. Too many of the creatures filmed, including the huge sharks, are members of a dying species.