If elephants didn't exist, you couldn't invent one. They belong to a small group of living things so unlikely they challenge credulity and common sense.

If the brain were so simple we could understand it, we would be so simple we couldn't.

Genes which allow females to be less inhibited leave fewer copies of themselves than genes which persuade them to remain highly selective. Among males, the best strategy is exactly the opposite one. The maximum advantage goes to those males with the fewest inhibitions. "Love 'em and leave 'em" is not so much a nasty peice of male chauvinist piggery as an accurate reflection of biological reality.

Before sight and sound hijacked our attention, we shared with all life a sort of common sense, a chemical sense that depended on direct contact with matter in the water or the air.

If you simply walk on the beach as we are doing, you have no special color. But if you travel with a purpose, it is different. When you go somewhere important or you return home from a long journey, you build a shape around you and it reaches out ahead to touch your destination.

It is a fascinating and provocative thought that a body of water deserves to be considered as an organism in its own right.

The limits of sensory evolution in fish are defined very largely by their habitat. Water is physically supportive, carries some kinds of odour well, and is kind to sound - letting it travel several times faster than air will allow, but it inhibits other more personal kinds of communication.