Pick of the day: The Wonder Of Dogs
8pm, BBC2
From huge dogs to tiny dogs, working dogs to lap dogs and hairy dogs to hairless dogs, Kate Humble finds out why this single species comes in so many shapes and sizes.
Meanwhile historian Ruth Goodman uncovers the surprising origins of the poodle’s famous haircut, finds out what makes greyhounds the fastest dogs on Earth and travels to the Highlands to meet hundreds of golden retrievers at their ancestral home.