Sharp 'hump' characteristic of the dorsal area noted especially on deep dives. Each whale has its own unique set of tail fluke designs, sort of like fingerprints. Scratches, variations of white and black, and even a distorted shape may help researchers to identify individual humpback whales. Scratches may be caused by the teeth of predators, since one of the humpback's primary defenses is it's powerful tail. During the breeding season, male humpback whales sing to perhaps establish territory or maybe attract females.
All males sing the same song during a season, though it is often rewritten, or altered.
The whale song is sung in a regular pattern for half an hour or longer. This same song may be continually sung for days at a time. Each season begins with the continuation of the same song from last season, though researchers have noted alterations to this song at the end of the season.