Following the BAFTA-winning series Inside Nature's Giants, this one-off special film goes beneath the surface of the giant squid. Long thought by many to be the stuff of legend, it was only in the late 19th-century that the giant squid was first officially recorded by scientists, after one leviathan squid washed up on a beach in New Zealand. Related to slugs and snails, this monster from the deep, along with its cousin the colossal squid, is the largest invertebrate in the world.

The BAFTA Award-winning series returns with a one-off feature-length Arctic special in search of the world's largest land carnivore: the polar bear. The Inside Nature's Giants team of experts join Inuit hunters and scientists studying these iconic creatures off the coast of Greenland. Polar bears have become a symbol of climate change as their habitat is threatened. And at the top of the food chain they are especially vulnerable to physiological side effects from man-made pollutants. Scientists have been monitoring the levels of toxic chemicals found in polar bears for over a decade. There are early signs of changes to their reproductive organs and neurological damage. The scientists collect blood and fresh tissue samples and collaborate with local people who are permitted to hunt a small quota of bears. The hunting is strictly controlled, using traditional methods and avoiding mothers with cubs.

In this Inside Nature's Giants Special, the BAFTA-winning team battle through the night against a rising tide to explore the mysteries of the largest predator on Earth: the sperm whale. Veterinary scientist Mark Evans and comparative anatomist Joy Reidenberg dissect the whale's enormous organs to reveal the secrets of this 45-foot deep-sea giant, which stranded and died on Pegwell Bay in Kent in March this year. Despite their enormous size, we know very little about sperm whales because their lives are normally hidden deep beneath the waves. The programme reveals how they can survive diving down thousands of metres for over an hour on one gulp of air in conditions that would freeze our blood and crush our bones.

Mark Evans and Joy Reidenberg travel to South Africa to dissect the first primate on Inside Nature’s Giants: a huge alpha male baboon that led a band of baboons on a rampage through a Cape Town suburb until the authorities were forced to euthanise him as he grew increasingly violent.