David Attenborough looks at the mammals that hunt insects. These creatures shared the planet with the dinosaurs, but when the giant reptiles disappeared they seized their chance to conquer new territory. David meets moles that swim through sand, a shrew that hunts underwater and another that sprints down polished running tracks so fast that most predators can't catch it.Some ancient insect hunters are surprisingly familiar. In his garden in London, David watches the seemingly painful act of hedgehog courtship.Giant anteaters and pangolins are less familiar, and perhaps the most bizarre-looking mammals on the planet. David meets a giant anteater first-hand. It may be dim-witted, but it also has the longest claws of any mammal - and the longest tongue too, which is just the job for a diet made up exclusively of ants and termites.Many insects can fly and are out of reach for ground-dwelling mammals, but early in the mammals' history, probably when the dinosaurs still roamed, the insect hunters took to the air. Spectacular aerial photography at night shows how these bats catch their prey, including one British bat - the natterer - that catches spiders from their webs without getting tangled in the silk.David takes his story full circle when he meets the world's strangest bat in New Zealand. When darkness falls, the bat drops to the ground, folds up its wings and hunts insects like a shrew.