Nature

Cities are growing at a faster rate than any other habitat on Earth. They may seem an unlikely place for animals to thrive, but they can be a world of surprising opportunity. Leopards prowl the streets of Mumbai, peregrine falcons hunt amongst New York's skyscrapers, and a million starlings perform spectacular aerial dances over Rome. In Jodhpur, langurs are revered as religious deities and in Harar, locals live in harmony with wild hyenas. Many animals, however, struggle to cope in the urban jungle. As the architects of this environment, can humans choose to build cities that are homes for both them and wildlife?

David Attenborough reveals the extraordinary ways that some animals use colour to hide and disappear into the background. New science reveals how the Bengal tiger in central India uses its orange-black stripes to hide from its colour-blind prey. In Kenya’s Masai Mara, the zebra’s black-and-white pattern confuses predators with an extraordinary effect called motion dazzle. And on the island of Cuba, a small snail uses colourful stripes in a surprising way to hide from its enemies.
Other animals use colour to trick and to deceive. On Australia’s Great Barrier Reef, a blue-striped blenny uses colours to mimic other fish and launch a sudden attack. In the grasslands of Zambia, the chick of a pin-tailed whydah mimics the patterns of its nest mates to ensure that it is not detected as an imposter. And specialist cameras reveal how a tiny crab spider uses bright ultraviolet colours to lure in its victims.

The story of Tilikum, a captive killer whale that has taken the lives of several people , including a top killer whale trainer, underscores the consequences of keeping these powerful animals in captivity, the problems within the sea-park industry, the man's relationship to nature, and how little has been learned about these highly intelligent and sentient mammals.
Tilikum was captured in the northern Atlantic Ocean in 1983 and taken to Sealand of the Pacific, a now-shuttered park near Victoria, British Columbia. Former Sealand trainers interviewed in 'Blackfish' say the park’s female killer whales would aggressively gang up on Tilikum, particularly when they were confined in a 20-foot-by- 30-foot pool overnight.

From the frozen poles to the searing deserts, this episode shows how animals have come up with strategies to survive the uneven amounts of sunlight that fall on our planet over the course of a year. The exception is on the equator, where the duration of day and night remain the same throughout the year. Here, this guaranteed sunlight drives the great diversity of life in the tropical jungles.

Weather controls the distribution of freshwater on Earth. David Attenborough narrates how this uneven distribution has given rise to an incredible diversity of species and habits, from the driest desert to the lushest tropical rainforest. Featuring a colony of ants banding together into a raft every time its home in the Amazon floods, a rain frog that manages to eke out an existence in one of the world's driest habitats on Earth, and the last wild camels that survive the Gobi Desert's bitter winters by eating snow that blows in from Siberia.

Oceans are the largest ecosystem on earth, covering two thirds of our world’s surface and providing half the oxygen in our atmosphere. They are home to as much as 80 per cent of all life on earth, and nearly three billion people rely on them for their primary source of food.
But our planet’s oceans would be little more than stagnant wastelands, and life on planet earth would cease to exist, were it not for one simple factor: a global network of powerful ocean currents. Every drop of seawater on earth rides these currents, taking 1,000 years to complete a single circuit. Without the constant mixing of currents, tides and waves, our oceans would stop supporting life - and a healthy ocean is vital to a healthy planet.