One extraordinary family of fish has achieved the ultimate form of gender equality. When it comes to breeding, seahorses do it like no other animal on the planet. Their fierce females refuse to be left holding the baby. So it's the males that carry their brood. In this episode we explore the world of mating seahorses which are the only animals in the world that have a major gender role reversal.

The plains of Africa, home to a powerful predator where females rule: spotted hyena. They have a reputation as dim-witted scavengers. But these fierce queens are the opposite; strong, fearless and highly intelligent. Hyenas are the girl gang of the Savannah. They hunt in packs, get first bite of their prey, and outrank every male in their group, making them some of Africa's most fierce queens.

David Attenborough explores Britain and Ireland’s grasslands, revealing the creatures that create them and the extraordinary stories they hide. From the coastal flower meadows in the Scottish Outer Hebrides to the rich open landscapes in the mountains of southern Ireland, we enter surprising and dramatic worlds.
In southern England, we meet an extraordinary bee that lives in chalk grassland, one of our rarest habitats, laying her eggs in empty snail shells. Meanwhile, in the colourful machair of the Hebrides, ringed plovers and lapwings strive to rear their families of tiny fluffy chicks and to save them for marauding gulls.
We travel back in time to explore the vast wild grasslands once found throughout our isles, before meeting herds of semi-wild horses, where males battle fiercely for the females. Today, they are helping to turn some of this land back to wilderness. And in our precious remaining pockets of flower-rich meadow, a remarkable conservation success story plays out. Once extinct in our isles, England now has the largest known populations of large blue butterflies. Their survival relies on a game of deception with red ants, which are tricked into adopting the butterfly’s unassuming but predatory caterpillars.
Our story then journeys to the mountains. Each morning in early spring, feisty male black grouse battle for prime position on their frozen breeding grounds. Their sole mission is to impress a female. Meanwhile, on south-facing scree slopes, dozens of adders emerge from hibernation to perform a surprisingly delicate courtship routine.
The episode concludes with a mighty battle in the wild mountains of County Kerry. This is the scene of an epic and spectacular rut between the largest land mammals in Britain and Ireland, red deer.
The grasslands of Britain and Ireland are under threat. We have lost 97 per cent of our species-rich meadows in the last century, as modern agriculture replaces these precious habitats. This episode shows just how important different types of grassland are to the species which call these islands home.

This episode includes footage of wildlife inhabiting underwater kelp forests, thousands of giant cuttlefish spawning along a restricted area of rocky reef off the south coast of Australia. Males outnumber females 11 to one, which leads to fierce competition. Larger males use brute force to drive off competition, while their smaller rivals use deception by mimicking the appearance of females. The programme also features tiger sharks hunting for green turtles in fields of seagrass and spider crabs trying to avoid predators while they shed their shells.

The world of invertebrates exists in a web of relationships with plants and other animals. Unique footage of the world's smallest insect (a fairy wasp only quarter of a millimetre long) shows it flying underwater to find the eggs of water beetles in which to lay its own brood. Some ants 'farm' the trees that give them shelter, creating areas known as 'Devil's gardens'. To make sure these grow without competition, they kill off other seedlings in the surrounding vegetation. The blister beetle's larvae huddle together on the end of a piece of grass and mimic a female bee. When a male bee tries to mate with the 'female', the larvae grab on to his belly. Confused, he flies away and searches for a real female. When he eventually finds her and mates with her, the beetle larvae hurriedly swap from his front on to her back, and hence get carried back to her nest where they eat her pollen supplies.

Dr Michael Mosley and Professor Alice Roberts investigate if male and female brains really are wired differently. New research suggests that the connections in men and women's brains follow different patterns, patterns which may explain typical forms of male and female behaviour. But are these patterns innate, or are they shaped by the world around us?" Using a team of human lab rats and a troop of barbary monkeys, Michael and Alice test the science and challenge old stereotypes. They ask whether this new scientific research will benefit both men and women - or whether it could drive the sexes even further apart.