Sperm whale society and culture is so different from ours that if they were sapient, we would have have to learn a new set of skills to understand them fully. Communication might well, at first, drift towards more practical matters.
Here is a video introduction to their societies and culture by Hal Whitehead, with further notes by me below.
The males and females live very different lives, with Hal concentrating on the better known females. Males leave their maternal pods between the ages of 4 and 21 years. Why they leave is not well understood, but one clue is that visits from giant solitary males make them at least as excited as the females in their pod, typically causing the immature males to deposit large quantities of semen into the ocean. I say ‘immature’ because even though they are clearly capable of mating, it seems that no female shows any interest in males until they have at least reached the age of 30. This might be what triggers them to leave then migrate to higher latitudes. As they do so they join up with others of their age, sometimes forming very large pods of a hundred or so. There seems to be no preferential associations (no special friends), nor stability of the membership within these fraternities. As the males get older their pods migrate closer to the poles, and the typical number of males in each lowers. It is in the Arctic and Antarctic waters that their bodies begin to grow far bigger than the females. Today they reach 40 tons but before whaling began some were even larger, perhaps reaching 70 tons. As they near those final weights, they appear to become solitary, and they begin returning to the tropics and subtropics where they socialise with females. I say ‘appear to become solitary’ because there is now convincing evidence that these giant males are in communication with their male neigbours at the poles, and will cooperate with them in the case of emergency.
We are only just beginning to understand the vocal cultures. The southern five he mentioned were comprehensive for for the South Pacific, but was not for the Caribbean and North Atlantic where more work must be done to tell if this is a multicultural assemblage or a single culture. Such distinctions are not arbitrary, as sperm whales will never vocalise with, or work alongside, members of another culture – as if they speak different languages, each unintelligible to the other.
There is one other well studied vocal culture worth mentioning – the critically endangered Mediterranean clan. This vocal clan is unique in having the males ranging over exactly the same territory as the females. There, the males vocalise with the coda of the females, and not with the ‘slow clicks’ exclusively used by males everywhere else.