The plant eaters take on the largely indigestible, spiny and poisonous defences of plants with some spectacular physical adaptations to diet.

Special tools like chisel sharp front teeth and underground dwelling enable this group of mammals to feast on roots and seeds.

A range of adaptations from sucker-feet to gripping tails help the tree dwellers to survive, and in the dark forest super senses come in to play.

The natural world was transformed when one great ape began to walk upright - us. But why has this led to the development of our extraordinary brains?