Whales have long been a profound mystery to us. They live in a world so removed from our own that we can barely imagine their lives. Their environment is different, their senses are different, their relationships are different. How might such almost alien creatures see the world?, Narrated by David Attenborough.

Horizon discovers what your cat really gets up to when it leaves the cat flap. In a groundbreaking experiment, 50 cats from a village in Surrey are tagged with GPS collars and their every movement is recorded, day and night, as they hunt in our backyards and patrol the garden fences and hedgerows. Cats are fitted with specially developed cat-cams which reveal their unique view of our world. You may think you understand your pet, but their secret life is more surprising than we thought.

In the past few decades, scientists have learned that the basis of everything they thought they knew about bird brains—that they were largely comprised of the most primitive and instinctual of brain structures—was wrong. Fully 75 percent of the brains of parrots and thousands of other species of birds is actually made up of a sophisticated information processing system that works much the same way as the locus of human higher-mindedness, the cerebral cortex.
The film shows scientists putting birds to the test. Can they solve problems? Can they cooperate? Do they feel emotion? New research demonstrates just how clever they can be.