Individual, unit and vocal clan level identity cues in sperm whale codas (The Royal Society)
"Sperm whales have a hierarchically structured society in which the largest affiliative structures, the vocal clans, are marked on ocean-basin scales by culturally transmitted dialects of acoustic signals known as 'codas'"
Multilevel animal societies can emerge from cultural transmission (Nature)
"...female sperm whales (Physeter macrocephalus) form matrilineally based social units with about 12 members each. These units are organized into clans with distinctive behaviour in several realms, including vocal repertoires, creating a multilevel society"
Young killer whale males learn dialect (Journal of Experimental Biology)
"...why killer whales acquire their dialect is a mystery and discovering the reason is particularly tricky because killer whales form incredibly stable family groups, making it almost impossible to study dialect acquisition."