Second smartest only to our trans-dimensional mouse overlords, that is. If you don’t know what I am talking about please catch up on your classic sci-fi literature here.
It has long been a popular opinion that dolphins are some of the smartest creatures on the planet. They have brains larger than those of humans, they often live in complex societal groups, and there may even be evidence of cultural evolution in some species’.
Did you know that Carl Sagan was once a member of a “secret society” whose goal it was to translate and understand the language of dolphins? It seems that there were several luminaries who believed dolphins spoke a sophisticated language similar to that of humans and that this language, if translated, could be used to decode alien languages. The group was called The Order of the Dolphin and the man in charge was John Lilly. You can read more about him here. Lilly played a big role in developing the sensory deprivation tank, which he actually used on dolphins. Other questionable research practices included giving LSD to dolphins. You will see that he was very into sensory experiences and the opening of the human mind if you read his wikipedia page. It is all very sci-fi (and also very 1970′s). This whole process may have been part of the inspiration for Douglass Adams joking that dolphins were smarter than humans in his books. (more info on The Order of the Dolphinhere)
Now, back to that whole dolphins on drugs thing…
A very interesting new series of studies is under way in which researchers observe dolphin culture and group dynamics through spy camera use. They are placing cameras inside of fake sea turtles and watching groups of dolphins. Through this less intrusive study mechanism, researchers have discovered that dolphins chew on puffer fish (which release a toxin when threatened) in order to get high. The Independent (a paper from the UK) has the story: http://www.independent.co.uk/environment/nature/dolphins-deliberately-get-high-on-puffer-fish-nerve-toxins-by-carefully-chewing-and-passing-them-around-9030126.html
Essentially, dolphins have figured out how much pressure to put on a puffer fish so that it will release a potent amount of drug, but not enough to kill/harm the dolphin, only enough to cause a trance-like state. In short, dolphins pass the puffer, get high, and then do this (if you didn’t click on this link, go back and click on it).
Dolphins have been known to use tools for quite some time, so this development is not entirely surprising. There is also evidence that tool use can be passed on through generations. In Shark Bay Australia there are groups of bottlenose dolphin known as “spongers” These individuals use sponges as fishing tools.
This behavior appears to have originated in one female and exists almost exclusively in female relatives of the original animal. Check out this paper from PNAS for more. There are now reports that dolphins in Shark Bay are using conch shells for fishing as well. A newer and more rare behavior.
In short, dolphins are fascinating. Are they are smart as we once thought? Maybe. They are certainly very interesting and even a bit unusual.