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  • [♪ INTRO]

  • Although, of course, not every person likes to get drunk or high,

  • there's no doubt that, as a species, we do have a bit of a fondness

  • for mind-altering substances.

  • You find them in every human culture that has ever existed.

  • And it seems like our feathered and furry friends also partake from time to time.

  • You might have read the news about wallabies getting high on poppy flowers,

  • or perhaps you've watched the hilarious video of a New Zealand wood pigeon

  • hanging upside down after eating too much fermented fruit.

  • Stoned or tipsy animals - they are internet gold, but, as you might expect,

  • most of these cases are anecdotal.

  • In fact, most examples of animals regularly seeking out intoxicants

  • kind of fall apart when researchers look closer.

  • Even some of the oldest and most well-known examples

  • like cats on catnipdon't hold up to scientific scrutiny.

  • So let's take a look at four infamous cases and see what science says

  • is really going on.

  • In 2013, the internet went berserk over a video showing dolphins apparently

  • getting high by passing around an inflated puffer fish andmilkingout its toxins.

  • After a few chews, the dolphins drifted motionless at the surface of the water

  • like they were super stoned, or justfascinated by their own reflection,”

  • as one zoologist said.

  • Observations of this weird behavior actually go back to 1995,

  • when researchers described it in rough-toothed dolphins.

  • But there are a few reasons to think this drug-seeking story is a bitfishy.

  • Like, for example, the main toxin in the fish's arsenal is tetrodotoxin or TTX,

  • and TTX is perhaps the worst choice for a party drug ever.

  • It works by binding to sodium channels in muscle and nerve cells and immobilizing them.

  • Anything more than a few micrograms of the stuff and mammals

  • experience headaches, vomiting, muscle weakness, and paralysis.

  • Too much leads to heart or lung failure.

  • There have also been cases of people going into a deep coma

  • where they're still fully conscious but can't move

  • which is not fun soundingsuper terrifying.

  • I don't like it!

  • The same could be said for a whole bunch of recreational drugs

  • most have toxic effects if taken in high enough doses.

  • But milligram for milligram, TTX is more than 2000 times as deadly as cocaine,

  • so there isn't a lot of room for error here.

  • Some animals, like garter snakes, soft-shell clams, and the pufferfish

  • themselves have developed resistance to the compound.

  • But it's unlikely dolphins have, because no mammals appear to be immune

  • to the stuff, and scientists know that dolphins can be killed by similar compounds.

  • So a more likely scenario is that the dolphins were simply playing with the puffer.

  • A puffed pufferfish is basically an underwater beach ball,

  • and dolphins have been known to be playful animals.

  • There are other observations of dolphins toying with living things

  • like, there was a pod of dusky dolphins off the coast of New Zealand that

  • passed around an octopus in the very same way.

  • It's fun for them - less fun for the octopus.

  • And that zoned-out chilling at the surface afterwards?

  • It's called logging, and it's what dolphins and whales do to rest

  • like they might do if they were tuckered out after a bunch of playing

  • with like an ocean beachballthat's actually a living thing.

  • Even if the logging was toxically-induced, there's no guarantee

  • the animals were enjoying the experience or desired to repeat it.

  • They might have been chilling at the surface because they were not, like, feeling good.

  • So although it is possible dolphins are doing their own version of the

  • puff, puff, pass, there is not any empirical evidence.

  • And a lot of reasons to think that it's not what's happening.

  • Tales of drunken elephants go back to 1839 when a naturalist reported

  • that Zulu guides told him they'd seen elephants get all weird and aggressive

  • after eating fruit from the marula tree.

  • The naturalist figured the fruit had spent too long on the ground and had fermented.

  • And it was pretty clear to him that the elephants ate this alcoholic fruit

  • because they, like us, enjoy getting tipsyit just so happens they're pretty mean drunks.

  • These stories are still told today.

  • But it turns out they are just tall tales.

  • It's true that elephants have a pretty varied diet which includes

  • leaves, grasses, tree bark, and fruit.

  • That fruit includes marula fruits, which will ferment if they fall and aren't eaten.

  • And these fruits can sometimes become an elephant's favorite food.

  • They're a good source of carbohydrates, and there are lots of them around

  • in the dormant season, when trees have shed their leaves and

  • high-quality calorie sources are scarce.

  • But, there are a couple of reasons this whole drunken elephant story

  • doesn't hold up--and they were outlined in a 2006 paper in

  • the journal Physiological and Biochemical Zoology.

  • First of all, elephants usually go for the ripe fruit on a tree's branches,

  • not the fermenting, alcoholic fruit lying on the ground.

  • But most importantly, the math does not add up.

  • Fermented fruits don't contain a ton of alcohol.

  • Assuming the fruit contained around 3 percent alcohol

  • which would be like a really weak beer-—

  • an elephant would have to eat 4 times its maximum daily amount of fruit to get drunk.

  • Being generous, we might try the calculations saying the fruits get up to 7% alcohol,

  • because that's the maximum percentage of alcohol captive elephants willingly drink.

  • Apparently we've done that study.

  • But even then, there's no way an elephant could eat enough fruit to get

  • the 27 liters of giggle juice it would need to become tipsy.

  • Elephants are very big!

  • So, I'm sorry, these giants are not using marula fruit as their night cap.

  • And the overlap between their strange behavior and the fruiting season

  • probably has a lot more of a straightforward answer.

  • The elephants could be acting aggressively because they don't want

  • some lanky apes stealing their prized marula fruit.

  • If you've ever really watched cowsespecially around here in Montana,

  • or in several other western US statesyou might have noticed

  • they sometimes just look a littleout of it.

  • Like, they just stare off into space, their head drooping,

  • or they're staggering around like they're on something.

  • Well, it's possible they've been hitting the locoweed.

  • That's the common name for the poisonous plants from the

  • legume genuses Astragalus and Oxytropis that produce the chemical swainsonine.

  • Swainsonine is a toxin that acts by inhibiting enzymes

  • inside of cells which normally break down other molecules.

  • When those enzymes are inhibited, the molecules build up,

  • and that can have some pretty nasty effects.

  • The animals stop eating and waste away, become less fertile,

  • miscarry or have babies that are malformed, or die of heart failure.

  • And because cows and other livestock eat these plants

  • despite all those negative effects, some have suggested they've become addicted.

  • But scientists have figured out that idea is also loco.

  • For example, a study from 1987 published in the Journal of Range Management

  • showed that cows born and raised on a paddock containing locoweed

  • eat similar amounts of the plant as newly introduced cows.

  • So experienced cowsones that could possibly be addicted

  • don't tend to eat any more than the cows that have never seen the stuff.

  • And, in a 1991 study on sheep, ewes that were loco-ed in the past

  • didn't seek out the plant a year later when they were given an area

  • with lots of room and different plants to graze on.

  • What's probably happening instead is that these livestock animals

  • are munching on locoweed when there are few other plants available.

  • Locoweed species grow early in the spring before other plants

  • and regrow in the fall, after many plants have died back.

  • Some varieties of locoweed actually taste pretty gross to cows,

  • but if there's not much else to eat, they're kind of forced to go for it.

  • And scientists think they may get used to the taste.

  • Then, they can pass this habit on to others.

  • In a 1994 study, cows that hadn't seen locoweed before increased

  • how much they ate of it after spending time around cows that had been trained to eat it.

  • So, in this case, it's not a drug habit - it's just a

  • eat whatever you can get your mouth on and also what everyone else is eatinghabit.

  • Which is the same thing I have.

  • Now it's no secret that cats go bonkers for catnip

  • hence the perpetual market for catnip toys, sprays and treats.

  • And way back in 1962, researchers at Harvard described

  • what they called the catnip response: that characteristic 10-ish minute reaction

  • where the cat goes from sniffing and licking to rubbing their face in the stuff

  • and rolling around and looking cute and all whacked out.

  • Later, some scientists went on to conclude that cats were experiencing hallucinations,

  • like seeing butterflies, and even likened catnip's effects to

  • how people respond to LSD or marijuana.

  • And from a chemical point of view, catnip could make sense as a feline party drug.

  • The active ingredients in catnip and other cat-attracting plants

  • molecules like nepetalactone or actinidinemight turn on some of the same

  • brain pathways that many hallucinogens do.

  • So it might seem like cats are a definitive case of drug-seeking behavior.

  • But...

  • No one has actually shown that catnip makes cats hallucinate.

  • That's just how a few scientists interpreted some pretty standard

  • pawing or rolling behavior.

  • It's not like they asked a cat to sit nicely in an MRI machine for a brain scan

  • or gotten them to paint their weird trips.

  • And the reactions to catnip are all behaviors the animals naturally do in a sexual context.

  • Like, all that rubbing and rolling over is how cats tell other cats that, like, they're into them.

  • In fact, scientists have gotten cats to perform the same behaviors

  • by exposing them to extracts of male cat urine.

  • So it seems like those catnip compounds are chemically similar to feline social odors

  • enough so to fool cats' noses, at least.

  • And that would mean all that licking and rubbing is them reacting

  • to what seems like the sudden, strong scent of another cat

  • with no visual dazzle orhighfeelings involved.

  • If it is a case of olfactory overlap, that could explain why only

  • two-thirds to three-quarters of cats seem to care much about catnip.

  • It's long been thought that some cats are just immune to the stuff.

  • But research in 2017 says that's not trueit's just that some cats don't react as overtly.

  • Instead, they just kind of chill out in a sphinx-like posture,

  • which may be because they aren't interested in the smell of a potential mate,

  • or are too young for that kind of thing.

  • But, when you get right down to it, cats and catnip isn't a great example

  • of animal drug-seeking behavior because they don't seek it.

  • Researchers say it's unlikely that wild cats self-administer the stuff.

  • If they did, you might expect there to be more wild cats hanging around areas

  • where catnip naturally grows.

  • Basically, if they really needed a hit, they wouldn't mind traveling a bit to get it.

  • But that's not the case.

  • There's no correlation between where cat-attracting plants grow

  • and where wild cats are found.

  • So, although most cats respond to catnip, their relationship to it isn't the same

  • as humans and mind-altering drugs.

  • There are lots of other potential cases of animal drug use which could be explored.

  • But so far, scientists haven't really found any evidence that

  • wild animals seek out chemical highs.

  • And that raises the question of why humans definitely do.

  • But to answer that, we have to dig deeper into how our closest relatives

  • and model organisms interact with mind-altering substances.

  • And that is an episode for another day.

  • Thanks for watching!

  • If you want to learn more about how other animals interact with drugs,

  • let me recommend our episode breaking down what happened

  • when scientists gave animals drugs in the lab.

  • And if this episode has you hooked on SciShow, be sure to click on that subscribe button!

  • [♪ OUTRO]

[♪ INTRO]

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B1 catnip fruit drug tipsy elephant wild

Do Wild Animals Intentionally Get High?

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    林宜悉 posted on 2020/03/30
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