Whales have complex social patterns, with speech patterns and dialects that vary by clan. Researchers from the Dominica Sperm Whale Project used underwater microphones to listen to sperm whales in the Caribbean and compared what they learned with data collected about sperm whales in the Pacific Ocean.
Whales, it turns out, have small families of 5 to 7 members that stay close together. In the Caribbean, but not the Pacific, individual whales apparently make friendships within the small family unit and spend a lot of time swimming together. There are also larger family “friendship” groups in which two or more small families may spend time swimming together for years over long distances. Again, this is observed in the Caribbean but not the Pacific. One step larger are the clans, which consist of families that all speak the same dialect of whale language.
Scientists have found 80 unique “codas,” or words, that sperm whales produce by emitting audible clicks. Whale clans have unique dialects used only by the families in the clan. By studying the dialects, researchers can identify, count, and track the locations and movement of clans. There are five clans in the Pacific Ocean and two in the Caribbean.
It’s within the clans that the Dominica Sperm Whale Project found evidence of different cultures and social habits. Researcher Shane Gero observed behaviors that were “uncoupled from natural selection” within sperm whale clans. The differences showed up not only in friendships and associations but also in hunting patterns, protection, and baby-sitting techniques.
The vastly greater distances in the Pacific Ocean may account for the difference in friendships observed between individual whales and family units. Whales in the Pacific range over much greater areas and are seldom observed swimming with the same whale (what would be considered a “friend” in the case of Caribbean whales). Likewise, families are spread further apart as well. Pacific whales may range from pole to pole, while whales in the Caribbean generally are within a 400-kilometer area.
While Pacific sperm whales don’t buddy up or hang with small family groups, they appear to have tighter bonds to their clans, particularly in protective roles. Researchers have suggested that whales in the Pacific ocean face many more predators, including Orcas, so the need for large group defense is more common than in the Caribbean.
