According to Gero, the clicks are not easy for the whales to master: ‘Young whales take at least two years to make these calls accurately enough. They babble before producing the right calls.’
Just as you don’t know everyone who shares your accent personally, whale codas extend beyond acquainted family groups. They learn them despite different pod families rarely or never actually encountering each other.
“All sperm whales do the same things: feed, swim, baby-sit and defend. But how they do it is different around the world”
Why all that effort? Gero thinks it functions as a kind of cultural identity. ‘Behaviour is what you do, culture is how you do it,’ he says. ‘All sperm whales do the same things: feed, swim, baby-sit and defend. But how they do it is different around the world. When two sperm whale families meet at sea, they need a way to recognise that they behave in the same way. Essentially, their special coda allows them to ask, “I am from the Caribbean, are you?”’
Gero hopes that the whale’s regional uniqueness will emphasise their recent decline and the importance of their protection. His long-term study suggests that the Caribbean population is in decline, perhaps by as much as four per cent per year due to human stressors such as chemical contaminants, fishing gear and ship strikes. ‘What we are losing is their cultural heritage,’ he concludes, ‘one that could not be replaced even if the global population can support remigration into the Caribbean.