Ice Age Giants - Season 1

The Ice Age odyssey begins in the 'land of the sabre-tooth' - North America, a continent that was half covered by ice that was up to two miles thick. Yet this frozen land also boasts the most impressive cast of Ice Age giants in the world.

High in a cave in the Grand Canyon, Alice discovers the mummified excrement of the loveable, grizzly bear-sized Shasta ground sloth. Lying in the sands of Arizona are the shelled remains of a glyptodon, surely the weirdest mammal that ever lived. On the coastal plains of California, Alice encounters the vast Columbian mammoth, an animal far larger than any elephant today.

These leviathans all have one thing in common: they were stalked by the meanest big cat that ever prowled the earth, armed with seven-inch teeth and hunting in packs - Smilodon fatalis, the sabre-toothed cat.

In this episode, Alice ventures to the parts of the northern hemisphere hit hardest by the cold - Europe and Siberia.

High in the mountains of Transylvania, a cave sealed for thousands of years reveals grisly evidence for a fight to the death between two starving giants, a cave bear and a cave lion. These animals, which would dwarf their modern-day relatives, were probably driven into conflict by the pressure on food supplies as the Ice Age gathered pace.

Yet Alice discovers that, for woolly rhinos and woolly mammoths, the Ice Age created a bounty. The Mammoth Steppe, a vast tract of land which went halfway round the world, provided food all year round for those that liked the cold. It was these mammoths that Europe's most dangerous predators - Neanderthals and our own ancestors - hunted for their survival.

Professor Alice Roberts journeys 40,000 years back in time on the trail of the great beasts of the ice age. This was the last time that giants like mammoths, woolly rhinos and sabre-toothed cats ruled our planet. Drawing on the latest scientific detective work and a dash of graphic wizardry, Alice brings the ice age giants back to life.

Astonishingly, even after thousands of years of ice crushing the northern hemisphere and temperatures of 20 degrees lower than those of today, many of the great giants of the ice age still walked the earth. It was only when the world had warmed up again that mammoths, woolly rhinos, sabre-toothed cats, giant ground sloths and glyptodonts finally became extinct. Alice sets off on her last voyage back to the ice age to discover why.

She learns the moving story of a mother mastodon, an extinct relative of the elephant. From her tusks, scientists can tell how many calves she had and whether they reached adulthood. This evidence, together with harrowing injuries on other skeletons, tells a perplexing story of a species on the edge of extinction - mastodons were turning on mastodons. By looking at the behaviour of elephants today, scientists have come up with a surprising theory as to why this happened.

The woolly rhino tells another story. Believe it or not, the one thing it couldn't stand was snow - which stopped it from getting enough grass. During the ice age in Europe and Siberia, snow was thin on the ground as so much water was locked up in the ice sheets. But when the ice ended, the snows increased, rhinos found themselves stuck and their little legs were unable to get them out of trouble.