The team are on a quest to find a fish that talks and the candiru - a parasitic catfish notorious for invading the human body. Kate heads deep into the jungle to film a rare freshwater dolphin and track down the elusive giant otter.
Many of the great rivers of southern Africa start high up in mountain ranges, power their way eastwards across wild forests and grasslands, and eventually empty out into the Indian Ocean. Ride the currents of these powerful bodies of water as they reshape the lives of the wild animals who rely on them.
Helen looks at volcanoes. With shocking eyewitness footage of eruptions, and new thermal imagery and ultra-high speed photography, we can now capture on camera the complex processes crucial to understanding how and why these forces of nature erupt.
As almost all animal inhabitants of Antarctica are forced to migrate north, the sea underneath the frozen ice still provides a home to many specially adapted fish whose cells are protected from freezing through an "antifreeze" liquid. Many of them feed on the faeces of other animals. The most notable larger animal that does not migrate north is perhaps the Weddell Seal, which can be found as close as 1300 kilometres to the pole. Groups of seals tear holes into the ice to dive for food and come up to breathe. The females come back to the ice to give birth.