UPDATE: Over at Science Sushi, Christie Wilcox, a grad student in marine biology, discusses this behavior in more detail, and doesn’t buy the “let’s get stoned” explanation, if for no other reason than tetrodotoxin doesn’t cross the blood-brain barrier, so couldn’t possibly alter perception. She imputes the pufferfish play as simple curiosity. In retrospect, I think she’s right, but time will (may, actually) tell. But toad-licking in dogs still remains a mystery! (Thanks to a reader and Matthew Cobb for pointing out her piece.)
More evidence on the intelligence of dolphins: like humans, they occasionally like to alter their consciousness with drugs. Since there’s no booze or dope underwater, they do it, according to an article in the Independent, by nomming on puffer fish:
In extraordinary scenes filmed for a new documentary, young dolphins were seen carefully manipulating a certain kind of puffer fish which, if provoked, releases a nerve toxin.
Though large doses of the toxin can be deadly, in small amounts it is known to produce a narcotic effect, and the dolphins appeared to have worked out how to make the fish release just the right amount.
Carefully chewing on the puffer and passing it between one another, the marine mammals then enter what seems to be a trance-like state.
The article isn’t clear about this, but perhaps they’re referring to the famous toxin in several genera of pufferfish that are known to the Japanese as fugu. As many of you know, fugu sashimi is a great delicacy in Japanese cuisine, partly for the reason that its liver and ovaries are deadly poisonous, so special chefs must be trained to prepare this dish. Not a small number of Japanese have been killed by foolhardiness and incompetent chefs.
The toxin in fugu is tetrodotoxin, which paralyzes the nerves of the respiratory system, causing death through asphyxiation. Wikipedia reports the death toll and a famous story:
Statistics from the Tokyo Bureau of Social Welfare and Public Health indicate 20 to 44 incidents of fugu poisoning per year between 1996 and 2006 in Japan (a single incident may involve multiple diners). Each year, these incidents led to between 34 and 64 victims being hospitalized and zero to six deaths, an average fatality rate of 6.8%.
. . . Much higher figures have been reported for earlier years, peaking in 1958 when 176 people died. According to the Fugu Research Institute 50% of the victims were poisoned by eating the liver, 43% from eating the ovaries, and 7% from eating the skin. One of the most famous victims was the Kabuki actor and “Living National Treasure” Bandō Mitsugorō VIII who in 1975 died after eating four servings of fugu kimo (fugu liver), whose sale was prohibited by local ordinances at the time. Bandō claimed to be able to resist the poison, but died several hours after returning to his hotel.
Note that it is the young dolphins who exhibit this behavior. I’m sure adult dolphins decry pufferfish as a “gateway drug” to harder stuff like jellyfish toxins.
Rob Pilley, a zoologist who also worked as a producer on the series, told the Sunday Times: “This was a case of young dolphins purposely experimenting with something we know to be intoxicating.
“After chewing the puffer gently and passing it round, they began acting most peculiarly, hanging around with their noses at the surface as if fascinated by their own reflection. [JAC: “Have you ever really seen the surface, man? Wild!”]
“It reminded us of that craze a few years ago when people started licking toads to get a buzz, especially the way they hung there in a daze afterwards. It was the most extraordinary thing to see.”
Well, when I was a young dolphin, I ate nutmeg, smoked banana peels, and took all the regular psychedelics of the Sixties, but I have to say that I never licked a toad.
Toads of the genus Atelopus do contain tetrodotoxin (including, I presume, my eponymous species Atelopus coynei), but the toads that people licked were probably various species of “psychoactive toads” that contain other poisons and hallucinogens. One of these is the cane toad, Bufo marinus, whose skin is poisonous. Nevertheless, Australia d*gs have been reported to lick these toads as a way to get high. LiveLeak has a report and a video of such a toad-licking d*g, who nearly licked his way to D*g Ceiling. Thus the behavior of these dolphins may not be unique, although its social aspects seem limited to cetaceans and humans.
The dolphins’ behavior was filmed by using artificial turtles containing cameras (videoa below):
The documentary makers used spy cameras hidden in fake turtles, fish and squid to film 900 hours of footage showing dolphins in their natural habitats.
The one above is apparently not viewable from the U.S., but this one is:
The first episode of the two-part BBC One program, “Dolphins: Spy in the Pod”, will be shown Thursday at 20:00 (description here). The dolphins’ consciousness-altering use of puffer fish will be shown in the second episode. I expect a report from readers.