Many of the traits we think of as uniquely human can be found in at least a handful of animal species, but names really are almost unheard of outside our species. The reason why I have to say "almost"? Look no further than everyone's favorite exemplar of non-human intelligence, the dolphin.
A team of researchers at Scotland's University of St. Andrews have found that bottlenose dolphins develop unique whistles that they use to call out to and identify their fellow members of the pod. This finding builds on previous research that had identified these unusual whistles, which would only be found in specific populations and clearly had some role in the communication process.
To better understand the purpose of these calls, Dr. Vincent Janik and his team recorded the various signature sounds for a population of wild bottlenoses, then played those sounds as well as some unfamiliar calls back to the dolphins. When a given sound was played, the dolphin to which it corresponded would answer back, which Dr. Janik argues is similar to a human acknowledging the sound of their own name. None of the dolphins responded to the unfamiliar sounds, which suggests these were not just random responses.
So why have dolphins developed their equivalent of names when no other known species (except maybe parrots) have done likewise? As Dr. Janik explains to BBC News, it might all be down to the distinct lack of other ways for dolphins to identify each other:
(Dolphins) live in this three-dimensional environment, offshore without any kind of landmarks and they need to stay together as a group. These animals live in an environment where they need a very efficient system to stay in touch. Most of the time they can't see each other, they can't use smell underwater, which is a very important sense in mammals for recognition, and they also don't tend to hang out in one spot, so they don't have nests or burrows that they return to."