Our planet was once populated by megafauna, big top-of-the-food-chain predators that played their part in balancing our ecosystems. When those megafauna disappear, the result is a "trophic cascade," where every part of the ecosystem reacts to the loss. How can we stay in balance? George Monbiot suggests rewilding: putting wolves, lions and other predators back on top -- with surprising results.
Sophie explores the world of silent communication in the animal kingdom and the human world - showing how much we can actually say without ever opening our mouths or making a noise. She reveals how some species have harnessed bacteria to generate light and how light messages are used by insects and deep-sea fish for a range of reasons, including attracting prey. Exploring how body language communicates huge amounts about us and other species, Professor Scott shows why a dog's wagging tail does not always mean it is happy and how humans can tell a lot about someone's state of mind from their posture alone. She reveals why yawns and smiles are contagious and how this can play a key role in social bonding and cohesion.
2/3 • Royal Institution Christmas Lectures: The Language of Life • 2017 • Nature
David Attenborough journeys to both Polar Regions to investigate what rising temperatures will mean for the people and wildlife that live there and for the rest of the planet. David starts out at the North Pole, standing on sea ice several metres thick, but which scientists predict could be Open Ocean within the next few decades. The Arctic has been warming at twice the global average, so David heads out with a Norwegian team to see what this means for polar bears. He comes face-to-face with a tranquilised female, and discovers that mothers and cubs are going hungry as the sea ice on which they hunt disappears. In Canada, Inuit hunters have seen with their own eyes what scientists have seen from space; the Arctic Ocean has lost 30% of its summer ice cover over the last 30 years. For some, the melting sea ice will allow access to trillions of dollars worth of oil, gas and minerals. For the rest of us, it means the planet will get warmer, as sea ice is important to reflect back the sun's energy. Next David travels to see what's happening to the ice on land: in Greenland, we follow intrepid ice scientists as they study giant waterfalls of meltwater, which are accelerating iceberg calving events, and ultimately leading to a rise in global sea level. Temperatures have also risen in the Antarctic - David returns to glaciers photographed by the Shackleton expedition and reveals a dramatic retreat over the past century. It's not just the ice that is changing - ice-loving adelie penguins are disappearing, and more temperate gentoo penguins are moving in. Finally, we see the first ever images of the largest recent natural event on our planet - the break up of the Wilkins Ice Shelf, an ice sheet the size of Jamaica, which shattered into hundreds of icebergs in 2009.
David Attenborough reveals that the animal inhabitants of this vast wilderness are every bit as extraordinary as they are bizarre. Unearthly calls of the notorious Tasmanian devil echo through the land, but following them over the course of a year reveals a surprisingly gentle side. In the dry east, rare white wallabies graze on the plains and jack jumper ants build huge nests – these venomous ants are amongst the most dangerous on earth. In the west, where it can rain nearly every day of the year, caves light up with the magical spectacle of thousands of glow-worms, and the trees are 100-metre towering monsters. Rivers are home to the peculiar platypus, and world’s largest freshwater invertebrate, the Tasmanian giant lobster. Miniature penguins come ashore to breed, and as winter approaches, the southern lights dance in the sky. Tasmania’s isolation and unique climate has created a world that is as weird as it is wonderful.
The next instalment describes the move from water to land. The fish that did so may have been forced to because of drought, or chose to in search of food. Either way, they eventually evolved into amphibians. Such creatures needed two things: limbs for mobility and lungs to breathe. The coelacanth is shown as a fish with bony fins that could have developed into legs, and the lungfish is able to absorb gaseous oxygen. However, evidence of an animal that possessed both is presented in the 450 million-year-old fossilised remains of a fish called a eusthenopteron. Three groups of amphibians are explored.
Liz Bonnin presents a controversial and provocative episode of Horizon, investigating how new scientific research is raising hard questions about zoos - the film explores how and why zoos keep animals, and whether they need to change to keep up with modern science, or ultimately be consigned to history. Should zoos cull their animals to manage populations? Liz travels to Copenhagen Zoo, who killed a giraffe and fed it to the lions, to witness their culling process first hand. They think it is a natural part of zoo keeping that is often swept under the carpet. Should some animals never be kept in captivity? In a world exclusive, Liz visits SeaWorld in Florida and asks if captivity drove one of their orcas to kill his trainer. But could zoos be the answer to conserving endangered species? Liz examines their record, from helping breed pandas for the wild to efforts to save the rhinos. She meets one of the last surviving northern white rhinos and discovers the future of this species now lies in a multimillion-dollar programme to engineer them for stem cells. Veteran conservation scientist Dr Sarah Bexell tells Liz the science of captive breeding is giving humanity false hope.