This episode of the documentary series focuses on the new giants, the heavyweights of the dinosaur world. It is only in recent years that experts have unearthed the biggest dinosaurs that ever lived. One monster eclipsed all others; more than seven times as heavy as diplodocus was the immense argentinosaurus - a single backbone was bigger than a human. For years, these giants were considered immune to attack from any predator - until the discovery of mapusaurus, a new giant killer whose fate appeared to be inextricably linked to argentinosaurus.
With scientist Kerisha Kntayya, Judi joins a crocodile hunt with a difference. Kerisha plucks young crocodiles out of the water. Judi then joins Kerisha's team as they wrestle an adult croc as part of the study Kerisha hopes will help save these prehistoric creatures. Judi, who's had a fascination with bats from an early age, also explores the Gomantong cave, home to more than a million bats.
The leatherback sea turtle is a magnificent creature that can be found in Atlantic, Pacific, and Indian Oceans. This ancient species swims faster, travels further, and dives deeper than any other reptile on the planet. In the Atlantic, they migrate every year from their nesting grounds in the Caribbean to the chilly waters off the east coast of Canada where they feast on jellyfish. This epic annual journey – at a staggering 12,000 km – is the longest for any reptile in the world.
The Belize Barrier Reef is the second-largest coral reef system in the world. Estimated to be nearly 4,000 years old, its waters are home to an immense marine ecosystem. Explore a deep blue wilderness brimming with rare, exotic fish, sea turtles, sharks, and huge green morays.
The giant panda gives birth to the smallest baby of any mammal and has to care for and protect it for many months. Why don't they give birth to more developed, robust young? The kiwi lays one of the largest eggs in the bird world, which produces a very well-developed chick. Why do kiwis produce a single egg that is a quarter of its body mass and almost too big to lay?
The sound of the cuckoo is to many the very essence of spring, yet behind the magical call is a bird that is a cheat, a thief and a killer. Just how does the cuckoo trick other birds into accepting its eggs and raising its young? Why don't the duped foster parents react as they watch the baby cuckoo destroy their own eggs and chicks? And why do they work so relentlessly to feed a demanding chick that looks nothing like them and will soon dwarf them? In this film, new photography is combined with archive footage and the latest scientific findings to solve a puzzle which, as narrator David Attenborough explains, has perplexed nature watchers for thousands of years.