This week we're going to learn about some animals that seem to have individual names! Further reading: Bottlenose dolphins can use learned vocal labels to address each other How Do Dolphins Choose Their Name? Vertical transmission of learned signatures in a wild parrot Baby Parrots Learn Their Names from Their Parents Study: African Elephants Address Each Other With Name-Like Calls Marmoset Monkeys Use Names to Communicate with Each Other The green-rumped parrotlet (photo by Rick Robinson, taken from this site): Show transcript: Welcome to Strange Animals Podcast. I’m your host, Kate Shaw. This week we’re going to learn about some animals that seem to be using names to refer to other individuals or themselves. Let’s start with bottlenose dolphins, because they’re well-studied and scientists have known about this particular aspect of their society for over a decade. Every bottlenose dolphin has a signature whistle that identifies it to other dolphins. The signature whistles can be complex and the dolphin may add or change details to indicate its mood or other information. It’s not precisely a name in the way humans would think of it, but it is an identifier. The dolphin creates its own signature whistle when it’s young. Some dolphins pattern their whistles on their mother’s signature whistle, while others mimic their siblings or friends. Some seem to pattern theirs on a distant acquaintance, which sounds to me like they just like something about an unusual whistle and decide to incorporate it into their own whistle. As dolphins grow up, females typically don’t change their whistles, but males often do. Male dolphins often pair up together and remain bonded, and a pair may change their signature whistles to be similar. When a dolphin is trying to find a friend it can’t see, it will mimic that friend’s signature whistle. If a mother can’t see her calf and is worried, she’ll do the same, and her calf will answer by repeating its signature whistle. A lost calf will imitate its mother’s whistle. But it’s even more complicated than it sounds, because a group of dolphins who get together to forage may choose a shared whistle that the whole group uses. This helps them coordinate their behaviors to work together. Each member of the group uses a slightly different version of the group whistle, which means that each member can identify who’s speaking. Other cetaceans seem to use a similar kind of name. Sperm whales, for instance, have a unique click sequence that they use to announce themselves when approaching other whales. The signature clicks always appear at the beginning of a sequence and don’t vary. Bottlenose dolphins and many other cetaceans are extremely social animals. So are parrots. Studies of parrot calls indicate that parrots appear to have signature calls that they use the same way as dolphins do, to identify themselves to other parrots and as a way for other parrots to call for them. A study of wild green-rumped parrotlets in Venezuela discovered that the birds give a unique signature call to each baby while it’s still in the nest, and the baby continues to use its call its whole life, often with small changes. The study set up video cameras to monitor 16 nests of a large wild population of the parrots. The population has been well studied and is used to using nesting tubes that scientists have set up for them. This makes it easier for the scientists to monitor nesting behaviors. In this case, to test whether the names had something to do with genetics or not, the scientists sneakily moved half of the eggs from one nest to another, so that half the parents unknowingly raised some chicks that weren’t actually related to them. Despite the egg switcharoo, all the chicks were given names that were similar to the parents’ signature calls. The parents started using a specific signature call soon after the eggs hatched, and the babies started imitating it.
