You have no doubt seen films or photographs of whales sending up impressive plumes of what looks very much like water. The usual cry of whalers is ‘Thar she blows!’ for this was and occasionally still is the way the whales are spotted. However, the spout is not so much water as steam. After a dive lasting perhaps up to hour, the used air in the whale’s lungs becomes hot and laden with moisture. As it rolls on the surface the whale opens its single nostril, the blowhole, and blasts this warm humid air into air which is often freezing cold. The moisture in the whale’s breath immediately condenses and it is this that pin points its position as a spout visible from a considerable distance.