In Douglas Adams’s hilarious classic, Hitchhiker’s Guide to the Galaxy, there are several animals said to be cleverer than humans. One – for the sake of irony – was the common lab mouse. The other was a creature that knew about the intergalactic bulldozers that eventually vaporized the planet and tried to warn us of the impending doom:

The last ever dolphin message was misinterpreted as a surprisingly sophisticated attempt to do a double-backwards-somersault through a hoop whilst whistling the 'Star Spangled Banner', but in fact the message was this: So long and thanks for all the fish.

It’s a fun punchline but it also reflects a long-held sentiment: that dolphins possess an unusual level of intelligence that sets them apart from the rest of the animal kingdom. In the popular consciousness it’s taken as a given that dolphins are highly intelligent, have complex behavior, and possess some kind of proto-language ability. However in recent months and years, a sort of backlash – or at least a re-alignment – has been fomenting on the periphery of animal behavior research.

Dolphin Exceptionalism

Dolphins’ revered status among animals really began with John Lilly, a 1960’s era dolphin researcher and psychotropic drug enthusiast who was the first to popularize the idea that dolphins are intelligent, later suggesting that they were even more so than humans. Lilly was eventually mostly discredited and didn’t contribute much to the science of dolphin cognition after 1970. Yet despite mainstream scientists’ efforts to distance themselves from his more bizarre ideas (that dolphins were spiritually enlightened) and even his tempered ones (that dolphins communicated in holographic images), his name seems inexorably linked to dolphin intelligence work.

“He is, as I am sure most dolphin scientists will agree, the father of the study of dolphin intelligence,” writes Justin Gregg in a book, due out in November, titled Are Dolphins Really Smart?

Since Lilly’s research, dolphins have been shown to understand signals given by television screen, distinguish different parts of their bodies, recognize their own images in mirrors, and have highly complex whistle repertoires that include some that seem to refer to specific animals (called signature whistles). But some of these ideas have been lately called into doubt. Gregg’s book is the most recent embodiment of the tug-of-war over neuroanatomy, behavior and communication – between the idea that dolphins are special and the idea that they’re on par with lots of other creatures.

Why the Big Brains?

The diminution of dolphins thus far has taken two main tacks: anatomical and behavioral. In the first category is a recent journal paper by anatomist Paul Manger, reiterating his long-held position that the large dolphin brain has nothing to do with intelligence.

Manger, an iconoclastic researcher with the University of the Witwatersrand in South Africa, has previously asserted that the dolphin’s large brain more likely evolved to help the animal retain heat than to carry out cognitive functions. That 2006 paper was widely criticized by the dolphin research community.

This new paper (also written by Manger alone) takes a critical eye towards brain anatomy, the archeological record, and oft-cited behavioral studies, concluding that cetaceans are no more intelligent than other vertebrates and that their large brains may have evolved for another purpose. Unlike in the previous version, he picks at many of the behavioral observations, such as the mirror recognition test profiled in the September 2011 issue of Discover, saying that they are either incomplete, incorrect, or go beyond the data.

Lori Marino, a neuroanatomist at Emory University and advocate for large-brained intelligence, says another multi-author rebuttal is now in the works.

Get Smart

The other argument, that dolphins behaviorally aren’t as impressive as has been claimed, is made by Gregg. A professional dolphin researcher (and voice-over actor for animated films), Gregg says he respects dolphin “accomplishments” in cognition research but feels the public and certain researchers have elevated them to a level of cognition beyond what the data suggests, and that other animals display many equally impressive traits. In his book, Gregg cites experts who call into doubt the value of the mirror-self-recognition test, an exercise thought to indicate some degree of self-consciousness. Gregg notes that octopuses and pigeons can learn to behave similarly to dolphins when given a mirror.

In addition, Gregg argues that communication has been especially oversold in dolphins. While certainly their whistles and clicks are a complicated form of audio signaling, he cautions that they show none of the hallmarks of human language (such as encompassing limitless concepts or freedom from emotion). He also mentions attempts to apply information theory – a branch of mathematics – to the information contained in dolphin whistles, citing others who question whether information theory is even appropriate for animal communication.

Gregg emphasizes that dolphins certainly display many impressive cognitive abilities – but that many other animals do as well. However his animals of choice aren’t altogether flattering: in the first chapter he insinuates that by many metrics chickens are as cognitively capable as dolphins. And later, conceding that dolphins can understand television screens, he writes: “Jumping spiders, with their eight eyes and brains so big for their body size that they spill over into their legs, seem equally as skilled.”

Gaining Traction?

It’s important to note that researchers like Manger are in the small minority among researchers who have examined dolphin cognition. Furthermore, even Gregg tries to distance himself from the idea that dolphins are mediocre, rather saying that other animals are cleverer than we thought.

But though it’s unpopular, perhaps the dull (or at least unexceptional) dolphin theory at least deserves consideration. Even Gordon Gallup, the behavioral neuroscientist who first used mirrors to evaluate whether primates are self-aware, expresses doubts about the dolphin’s capacity for this humanlike ability.

“The evidence for mirror self recognition in dolphins is tenuous. It’s not substantive,” Gallup told me in 2011. “[Videos taken during the experiment] are far less compelling in my opinion. They’re suggestive but hardly definitive.”

Arguments against dolphin exceptionalism boil down to three basic ideas. One, as Manger seems to press, is that dolphins simply aren’t any smarter than any other animal. Two, it’s difficult to compare any one species against another. And three, there simply isn’t enough good research on the topic to make solid conclusions.

In Are Dolphins Really Smart? Gregg himself isn’t able to do much to answer his own question beyond “Yes, they’re pretty smart.” They cannot teleport or do high-level mathematics, but we knew that. And don’t plan on getting any kind of warning before the world is obliterated by intergalactic bulldozers.

Erik Vance is a science writer based in Mexico City. He writes about the environment, brain science, and occasionally hamster sex. Read more of his writing at the Last Word on Nothing.