From the stealthy tarantula to the prehistoric Komodo dragon to the deceptive mosquito--one of the more prolific modern predators--killers come in all shapes and sizes. Join us as we examine the deadly adaptations of these cold-blooded culprits.
The episode begins in the South American rainforest whose rich variety of life forms is used to illustrate the sheer number of different species. Since many are dependent on others for food or means of reproduction, David Attenborough argues that they couldn't all have appeared at once. He sets out to discover which came first, and the reasons for such diversity. He starts by explaining the theories of Charles Darwin and the process of natural selection, using the giant tortoises of the Galapagos Islands (where Darwin voyaged on HMS Beagle) as an example. Fossils provide evidence of the earliest life, and Attenborough travels a vertical mile into the Grand Canyon in search of them.
Bat populations are plummeting from a seemingly unstoppable fungal infection. Meanwhile, northern flying squirrels are being crowded out by their southern cousins. Learn about the life-or-death challenges faced by key wildlife in two of the Great Lakes region's most delicate ecosystems.