The Blow: The first sign that whales are around is usually the blow. A humpback breathes through the blow hole on top of its head. When it expels its breath, the resulting burst of air and water vapor can be seen for as far away as two kilometers on a clear day. The breath rushes out at speeds up to 450 kph and can go up to a height of 5 meters. It has a fishy smell and has sufficient oil content to put an unpleasant smear of oil on a camera lens if a photographer gets too close.
Breaching: A much more spectacular way of announcing its presence is for a whale to breach. With 2 or 3 beats of its huge tail the creature hurls itself up through the surface sometimes clearing the water completely, and then falls on its back with a tremendous splash. Breaching is thought to communicate position to others. The splash can be heard for several kilometers.
Calves: A humpback calf normally swims along in close company with its mother.
Head Lunge: When a whale breaks the surface and falls forward instead of backward the action is called a head lunge.
Spy Hop: Humpbacks are curious, and often pop their head up above the waterline to look around. The creature raises its head vertically from the water until the eyes are exposed, maintains that position for a short period of time and then lowers its head back into the water. This common behavior is thought to be used mainly for orientating themselves with the shoreline during migration.
Pectoral Fin Extension: Humpbacks are often seen waving their huge oar-like fins above the water. The creature lies on the surface and lifts one or both of its pectoral fins up out of the water depending on body position. Once extended, the fins can be waved about.
Tail Extension: Sometimes humpbacks are seen with their tail flukes extended above the water for up to 15 minutes at a time. This behavior is rare but could be to do with feeding, as a calf is often seen bobbing around its mother's tail at this time.
Tail Slapping: Whales like to lift their huge tails high above the water and slap them down on the surface making a tremendous splash. This can be heard for great distances by others and is probably associated with marking position. Because of the formidable power of the tail, this behavior should be interpreted as aggressive and the creature should be given plenty of room.
Peduncle Slap: The peduncle is the muscular part of the body nearest to the tail flukes. It is used in a variation of the tail slap where the tail is slapped in a sideways movement like a massive karate-chop. This movement is a sure sign that the creature could become aggressive.
Tail Cocking: Tail cocking is another sign of aggression that is used when stressed. An aggressor can cock its tail up in the air and then bring it down heavily on an opponent in a disagreement over territory. Humans should keep well clear.
Tail Slash and Tail Swish: Two further movements of the tail involve slashing from side to side in the water and swishing on the surface to create turbulence. Both these activities are also associated with aggression. Crews of whale watching boats watch for these behaviors as signs to move away.
Pectoral Stroking: Pectoral fins are the equivalent of human hands. They are frequently used to stroke the body of another of the same species, probably during courtship and mating. Mothers and calves also stroke one another as a display of closeness.
Pec Slapping: The humpback has the largest pectoral fins of any of the great whales. The fins alone can weigh up to several tonnes! When brought down onto the water from the extended position they create a forceful splash which can be heard from quite a distance, both above and below the surface. Pec slapping is a common behavior among humpbacks, thought to be used as a form of communication.