The first sign that whales are around is usually the blow .
Humpbacks breathe through the blow hole on top of their head.
When it expels its breath, the resulting burst of air and water vapour can be seen for as far away as two kilometres on a clear day. The breath rushes out at speeds up to 450 kph and can go up to a height of 5 metres. Not surprisingly, cetacean breath has a fishy smell and has sufficient oil content to put an unpleasant smear of oil on a camera lens if the photographer gets too close. With 2 or 3 beats of its huge tail the creature can hurl itself up through the surface, sometimes clearing the water completely, and then fall back down with a tremendous splash. The reason for breaching is thought to be to communicate position to others.