Chris reveals some of the cleverest animal communicators on the planet. For decades, people have longed to emulate Dr Doolittle and be able to understand what animals are communicating to one another. But their methods often go far beyond the capabilities of our human senses. Now, thanks to dedicated researchers, new science and cutting-edge technology, we're being given a glimpse into the ingenious ways that animals get their message across - that dolphins have individual names for each other, that cuttlefish use covert signals, and that humans can understand apes without even realising it.
Ch1. Oceans In Cape Verde, Gordon starts the adventure with a look at one of the world's largest populations of nesting loggerhead turtles. He then heads to the Bahamas with Caribbean reef sharks, California to see young elephant seals and the British Isles to attach featherweight cameras to a squadron of gannets. Ch2. Australia In New South Wales, Gordon encounters a marsupial facing a complex set of challenges when he meets a population of kangaroos that are being pushed to the very brink by a coastal development boom. How are they surviving on the edge of this urban expansion? Gordon meets the scientists driven to find out more about what the roos are feeding on as they are pushed onto the coastal fringes. As we become immersed in their world, we get a better understanding of kangaroos' social lives and the impact of human encroachment on their diet. In southern Australia, we head to Adelaide, where one of the team's toughest challenges yet is to create the lightest of cameras to find out what the lure of the big city is to a colony of newly arrived fruit bats. Their appearance is a bit of a puzzle. Are they a threat to the local commercial fruit crops or have they found other ways to adapt to city life? For the first time ever, the fruit bats take our cameras up above the cityscape, showing us a unique view of their nocturnal worlds while providing information crucial to their future. In Queensland, we help scientists find out if koalas really deserve their dozy daytime reputation when we join researchers at a reserve to discover some incredible revelations surrounding their night-time manoeuvres. The team's tech allows us to shadow them after sundown, unveiling their remarkable agility and surprising navigational skills. Specially designed with tree-hugging in mind, koalacams offer an insight which could help koalas as we find out what they need to survive - not just here, but elsewhere in the country.
As the expedition team near the end of their journey across Micronesia, it's a race against time for the extreme deep divers as they continue their search for new species. As Kate Humble explores the Rock Islands of Palau, Mike DeGruy embarks on a unique training programme. The Newtsuit is an incredible feat of submarine engineering - a bright yellow one-man submersible that Mike has to master before he can venture even deeper into the Pacific abyss.
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.