The sky is a crowded world where mammals, birds and insects hunt, escape, mate, defend territory, sleep, and even die on the wing. Survival up here depends not just on beating gravity or mastering flight, but also out-flying the competition.

Hopping is key to the most efficient form of locomotion on land. Unlike running animals, when a kangaroo speeds up its legs don’t have to move faster. Simply by altering the angle of take off they can increase the distance they fly with each hop.

Whooper swans are built for speed. They have long, pointed wings with stiff primary feathers to enable them to migrate between their summer breeding grounds in Iceland and their wintering ground in the UK. But when you’re built for top speed, acceleration is a sluggish affair.

The Anna’s Hummingbird is so fast that it harnesses the air around it to produce a sound – angling its tail feathers as it reaches top speed so they resonate and hum – a sound that the female finds irresistible.

A flock is one of the most spectacular sights in nature – but how does it work? The explanation comes down to some surprisingly simple rules that each bird applies to its seven closest neighbors.

The Night sky is the backdrop to an arms race that has been played out for millions or years between billions of bats and billions or moths, where aerial dominance is decided by the tiny advantages in flying skill and sensory equipment.

The secret to Brazilian free-tailed bats’ success is safety in numbers, and their highly adaptable wing. Much like our hands its able to change its shape in all three dimensions, making the bat perhaps the ultimate flying machine.

With long thin wings, and a nose that can see the movement of the air around her, a royal albatross can use the power of the wind to fly for free.

Wood ducks make a nest high in the trees to protect their eggs from predatory woodpeckers, raccoons, snakes and alligators. Although the eggs are laid over a two-week period they all hatch on the same day and the mother has just minutes to get the twelve noisy chicks to safety.

Caracals are adapted to catch birds in flight and capable of leaping up to 3m high. Enormous back legs maximize the caracal’s speed on take off and special muscle fibers deliver three times the power of a human athlete’s.

Gliding allows flying squirrels to find scarce food fast, even in the depths of a North American winter. The longest limbs in the squirrel world make their wings as large as possible. But flights are kept short and fast to help the squirrel avoid a major predator – the Great Horned Owl.

How do animals take to the air in the first place? Each of the incredible creatures we’ll meet has its own special techniques. But they must all overcome one of the planet’s most powerful and universal forces – gravity.

Many animals take to the skies for a split second, but to stay there the planet’s strongest flyers have to push the laws of physics right to the edge. Explore the extremes of true flight: Power, acceleration, top speed, maneuverability and endurance.

In his short life, this giant beetle has to find a mate, so to speed things up, he takes to the skies. As his wings move down, he produces lift much like a bird, but he also twists his wing at the end of each wing stroke.