Do dolphins really call each other by name?

In a sense, yes, with caveats. Each bottlenose dolphin has a uniquely identifying signature whistle, believed to be the most name-like signal found so far in any non-human animal. Dolphins sometimes copy another dolphin's whistle back to address that particular animal, and a University of Chicago study found they remember the whistles of animals they had lived with after 20 years of separation. But no dolphin language has been found, so a whistle works like a name tag, not a word in a sentence.

The whistles are made without vocal cords: dolphins produce sounds using six air sacs near the blowhole. Mothers use theirs to keep in touch with their calves. In recordings of 19 mothers, every one changed her own signature whistle when her calf was present, using a higher frequency or a wider range, much as humans use a higher pitch and a wider range when speaking to children.

Beyond names, how smart are dolphins? A bottlenose dolphin's brain is slightly heavier than a human's, but brain size was once taken as a major indicator of intelligence and many other factors also matter. Researchers who compare problem solving tend to rank dolphins at about the level of elephants, not above other highly intelligent animals.

So the best answer is a careful one. Dolphins have individual sound identities, strong memories and learned traditions, and they are clever. But the popular picture of a talking, super-smart dolphin goes further than the evidence.