12/12 A look at the many and varied ways that animals ensure their genes are passed on.
11/12 David Attenborough examines courtship rituals in the animal kingdom.
10/12 David Attenborough examines the methods of communication in the animal kingdom.
9/12 David Attenborough examines how recognising friends is vital in the animal kingdom.
8/12 Aggression is widespread in animals. But teeth, hooves and horns can cause severe injury.
7/12 David Attenborough looks at how animals form partnerships.
6/12 David Attenborough looks at how animals build their homes.
5/12 David Attenborough looks at how creatures find their way around the earth.
4/12 David Attenborough looks at the life-and-death duels which are fought daily in the wild.
3/12 David Attenborough looks at the ingenious ways animals solve the problem of finding food.
2/12 From creches of bats to elephant babysitters, a look at how animals bring up their young.
1/12 How animals employ an extraordinary variety of techniques to disperse their offspring.