After a while, they gave up trying to reach the carcass and led their cubs down the riverbank to the old stinking bait.

The programme begins at the arrival of spring, with a grizzly mother leading her cubs down from their winter den in the Alaskan mountains.

For as I soon learned, it was not a potentially hull-breaching iceberg that had seized the captain's attention, but a big creamy polar bear, leading her two cubs across the pack.

Hormoz Asadi, an Iranian field biologist and a member of the World Conservation Union's Cat Specialist Group, said in a telephone interview from Tehran that the cheetah's mother led her three cubs into the town of Bafq.

She needs food and must lead her cubs to her hunting ground on the sea ice before it begins to break up.

A female polar bear leads her two cubs across the sea ice.