It's no secret that animals occasionally get high and drunk off the many vices nature has to offer. However, intentionally doing so has always seemed a strictly human affair. Now more and more evidence is piling up that suggests wild animals enjoy a good buzz as much as the next guy, and may even have their fair share of junkies - an idea that experts are now fiercely debating.

Passing the Pufferfish

One of the most iconic and stunning examples of what is best described as "substance abuse" in nature actually first made its debut January of last year. In the documentary Dolphins: Spy in The Poda team of scientists and videographers pooled their expertise to capture nearly 900 hours of close-and-personal footage of dolphins off the coasts of Mozambique, Canada, Florida, South Carolina, Honduras, Costa Rica, Australia, South Africa and Argentina.

A John Downer Productions team pulled this off by using a fleet of nine realistic "spy creatures" - ranging from turtles to nautili - complete with remote control and hidden cameras.

It was one of these clever cameras that managed to film a gang of teenage dolphins horsing around. They were playing what can best be described as a game of "pass the puffer" - hunting down and capturing a toxic pufferfish only to start passing it around almost like in a game of catch.

Days before the segment first aired, Rob Pilley, a zoologist who worked as a producer on the series, told the British Sundays Times that this was incredibly unique footage that would have viewers and scientists alike talking.

"After chewing the puffer and gently passing it round, they began acting most peculiarly," he explained, "hanging around with their noses at the surface as if fascinated by their own reflection."

To understand exactly what was happening, it's probably best to watch the scene for yourself, even as narrator and renowned actor David Tennant helps spell things out. (Scroll to read on...)

[Credit: John Downer Productions]

"This was a case of young dolphins purposefully experimenting with something we know to be intoxicating," Pilley pressed, going on to argue that the delicate expertise with which the "gang" handled the puffers seemed to imply they've done this before.

Since then, some experts have argued that this is a compelling example of intentional substance abuse in the natural world - evidence that backs anecdotal tales of other animals doing the same.

Dogs, Trippy Toads, And 'Extraterrestrial' Wallabies

Six years ago, Lara Giddings, the attorney general for the island state of Tasmania, stepped up during a parliamentary hearing concerning the security of the nation's poppy fields. Normally, these kinds of meetings consist of talks about keeping people out - namely criminals who would plunder what makes up nearly 50 percent of the world's legally grown opium.

However, this time around Giddings wanted to talk about wallabies - those adorable little kangaroo-like mammals that Australia proudly boasts.

And what we're these little rascals up to?

"The one interesting bit that I found recently in one of my briefs on the poppy industry was that we have a problem with wallabies entering poppy fields, getting as high as a kite and going around in circles," Giddings told the hearing. (Scroll to read on...)

This was offered as a practical explanation for a smattering of crop circles which had appeared in poppy fields in recent years, and the attorney general had the word of local farmers to back up her strange hypothesis.

"Then they crash," she added, suggesting that wallabies could actually be found asleep in plundered fields. "We see crop circles in the poppy industry from wallabies that are high."

But she wasn't just mentioning this to explain for agricultural graffiti. It was also a testament of what threatened these fields, where wallabies looking for a fix in the dead of night might be hard to deter.

And these little hoppers aren't the only animals in the Down Under who are stubborn junkies. A 2011 documentary titled Cane Toads: The Conquest detailed another unusual instance of animal self-drugging.

Megan Pickering, an Australian veterinarian featured in the documentary, described how she has seen numerous cases of domestic dogs deliberately hunting down and licking semi-poisonous, invasive cane toads - an action that would, as far as veterinarians understand, be like an LSD trip.

"It just seem unbelievable that an animal would go back for a second try," she said. "But never-the-less, we do have many documented cases of patients who deliberately - on a regular basis - seek out the toads."

If curiosity has gotten the better of you, check out the story of Dobby the dog - an excerpt from the complete documentary made available by Radio Pictures and director Mark Lewis. (Scroll to read on...)

[Credit: Cane Toads: The Conquest ]

Reason For Doubt

Still, the question remains: is this really deliberate behavior or rather strange and uncomfotable incidents? The dolphins for instance, certainly looked like they were having a good time, but the right music and camera angles can sell practically anything.

And in the case of sweet little Dobby, well... let's be honest... dogs aren't always the brightest of pets, and most owners will readily admit that their dog will lick just about anything and won't always learn from the consequences. How many times do you think it takes for your average canine to learn not to run through a prickly bush? Most would say "a lot."

Christie Wilcox, an evolutionary biologist and the writer for Discover Magazine's Science Sushi, gave her two-cents to make the argument that in nature, when animals are under the influence, it's probably a mistake.

She brings up the "Spy in the Pod" clip in particular, arguing that those were not happy dolphins on a good trip, but the equivalent of a gang of teenagers learning thier lesson in a near-death experience.

"Tetrodotoxin (pufferfish neurotoxin) doesn't make sense as a narcotic because it is far more deadly than any of the substances used recreationally [by humans]," she wrote in her blog. "Milligram-for-milligram, tetrodotoxin is 120,000 times as deadly as cocaine, 40,000 times as deadly as meth, and more than 50 million times as deadly as THC (the psycho-active component of marijuana)."

The toxin, even diluted in the ocean, is so concentrated that it can induce "locked-in syndrome." This is when clear-minded victims actually recognize that they no longer have control over even the simplest of body actions.

"While dolphins may play with puffers to see them expand, or even foolishly put one in their mouths... I find it tough to believe that dolphins are so careful that they can walk the fine line between tingly lips and maddening paralysis," Wilcox pressed. (Scroll to read on...)

Supply, Demand, and Alcoholism

And that's not the only argument against the idea that there are 'junkie' animals out there. Robert Dudley, a professor for the University of California's Department of Integrative Biology, added that evolutionarily, most of the psychoactive substances in nature exist as a line of defense against predators.

It wouldn't make much sense for a plant like spotted locoweed (Astragalus Lentiginosus) - a 'favorite' of tripping cows and horses - to develop a toxin if it actually wound up encouraging consumption. That's also probably why toxins in plants aren't exactly common, and vary heavily from region to region.

However, in the case of alcohol, Dudley adds, it's a very different story.

"If you look at the taxonomic distribution of alkaloids, they are very consistent," he said in an interview with Nature World News (NWN). "They are all over the place... and animals are going to be exposed to them all the time."

Dudley is the man behind what is commonly called "the Drunken Monkey Hypothesis," a popular theory that claims that alcohol consumption among human ancestors helped shape our predisposition towards the substance today.

The argument is described in detail in his book, 'The Drunken Money: Why We Drink and Abuse Alcohol,' an intriguing read published just last year.

"It's a very fundamental part of human behavior to drink alcohol," Dudley told NWN. "No matter where you are in the world, people are drinking and they are doing it even as a social behavior and you've got to wonder, 'Why? What's up with that?' Could it really be just a happy accident? Or is there something really more deeply imbedded?"

To find out, the researcher has looked at our closest modern relatives to see how they handle their booze. It is known that chimpanzees, for instance, supplement their diets with a ton of fruit (namely grapefruit), eating it a stunning 90 percent of the time. There are even fruit specialists, such as lowland gorillas, orangutans, and gibbets, who all eat about five to 10 percent of their bodyweight in fruit daily. (Scroll to read on...)

That's because in the wild, these animals are "calorically challenged," as Dudley calls it - constantly needing sources of fast energy like sugar to keep going.

"And in nature, where there is sugar, there is alcohol," he said.

Dudley explained how experts have known for a long time that fruit flies zero in on fermenting fruit not by following their sickly-sweet smell, but by tracing hints of alkaloids dancing in the air.

"It's the same reason that when you have a glass of beer or wine outside, magically these little fruit flies start to appear when you didn't see them moments ago."

It may not be all that different, then, for apes and human ancestors.

"The idea is that, number one, it serves as a long-distance signal for the presence of sugars, because where the is alcohol there is sugar," the researcher added. "And then number two, when you get there, the effects alcohol have on body and mind may actually help facilitate consumption."

That second part isn't exactly a secret either. It's been well studied in humans, and is a phenomenon that restaurants know to take full advantage of - explaining for happy hours and the mark-up served alcohol sees compared to the liquor store variety.

However, Dudley said that apes "never get drunk because the concentrations [of alcohol] in the fruit are so low and/or they have good enzymes to metabolize the stuff - their stomach fills before they can get a high blood alcohol level."

He adds that the crux of his hypothesis is that because it is literally everywhere in nature, the presence of alcohol may have become evolutionarily associated with nutritional reward.

A past study published in the journal Proceedings of the National Academy of Sciences (PNAS), and edited by Dudley, even provides genetic evidence for this theory. (Scroll to read on...)

Researchers long thought that humanity received a super-boost to our alcohol dehydrogenase enzyme, ADH4, a mere 9,000 years ago, when settled humans started fermenting surplus foods.

However, the reverse genetic sequencing of 19 modern ADH4 proteins showed that a 10-million-year-old ancestor of humans, chimpanzees, and gorillas sported a version of ADH4 that is 40 times more efficient than even the modern primate ADH4 - meaning that this ape could eat a ton of fallen fruit without worry.

A little bit of a buzz, however, also may have been a good thing, as study author Matthew Carrigan explained, because fallen fruits were a food source that was to be taken advantage of whenever possible.

"It was hard to get too much of this sort of stuff," he said, "so when you found it, you wanted to be programmed to over consume."

Dudley suspects that this programming may be the problem humanity sees today, where some people are too genetically predisposed to alcoholism.

"This could be the case of a sort-of evolutionary mismatch" he explained, "between the way [modern] society wound up - with high concentrations of readily available alcohol (demand driven) - and the world primates live in, which remains supply driven."

In the natural world, he added, you're always going to be getting alcohol from food or even nectar, where overconsumption can only be good for you.

"What I get a lot from critics is that this is just a happy accident," Dudley added laughing. "They say 'it just happened to be that way, therefore it is', but you could make that argument for everything."

Likewise, you could even make that argument for tripping dolphins and psychedelic toad-licking. It's looking for an "evolutionary background," the researcher pressed, that's important.

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