Despite their reputation for exceptional intelligence, dolphins may not be as brilliant as commonly believed. Recent reviews of the literature suggest that while dolphins are clearly quite intelligent, when compared with other animals they don’t stand out so much. Where did their reputation for intelligence begin? And how does intelligence in animals develop in the first place?

As far as the first question, Scott Norris, writing in Bioscience, says that “the notion of advanced dolphin intelligence was planted in the public imagination in the 1960s by maverick scientist Scott Lilly”. Lilly was enamored of dolphins and spent years trying to teach them to speak. Lilly’s experiments never went anywhere and often bordered on the unethical, even immoral, but he is not alone in tying language to most notions of advanced intelligence. Complex communications are born from social systems, as social interactions require other traits associated with intelligence. Some examples are forming and remembering social ties, learning new behaviors, cooperating—in other words, culture.

In this regard, dolphins do exhibit a lot of the behaviors and practices associated with culture and advanced intelligence. Norris notes that more sophisticated studies of wild dolphins and whales reveal vocalizations diverse and specific enough to potentially be considered language. Dolphins do learn new behaviors easily and mimic others with ease. They keep track of complicated social hierarchies within and across groups. They have even been known to invent new behaviors in response to new situations, which, according to Norris some researchers consider to be the “very hallmark of intelligence.” More than that, dolphins may even be able to teach each other these new behaviors. Norris describes some dolphin populations using sponges to protect themselves from scrapes, and passing on the technique to others. Such transmission of practices is considered by many to be indicative of a nascent culture.

So dolphins are exceptionally intelligent, right? Not so fast. They seem to be more intelligent than many species but these behaviors are by no means unique to dolphins. Many animals, e.g. wild boar, dogs, primates, or sea lions, to name a few, also have highly complex vocalizations, social relationships, and an ability to learn, mimic, and adapt to new situations that is just as sophisticated. Many of these skills, such as learning, are actually more advanced in other species than in dolphins. Cultural transmission, if proven in dolphins, is less common, but not as many animals are as widely studied as dolphins, either. More examples may yet be uncovered.

The issue is not so much are dolphins intelligent, since on some level they clearly are, but are they more intelligent than other animals, and that is unclear. Dolphins have the fortune (or misfortune) to be highly anthropomorphized. Many species of dolphins have a facial structure that really makes them appear to be smiling, something never said about, say, a wild boar. Looking at that grinning face, we started to see ourselves in dolphins, and when we see ourselves we see what we expect to see. So how smart are dolphins? Let’s say at least 75th percentile.