[♪ 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 catnip—don’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 and “milking” out its toxins. After a few chews, the dolphins drifted motionless
at the surface of the water like they were super stoned, or just “fascinated
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 bit… fishy. 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 sounding… super 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 beachball… that’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 tipsy—it
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 cows—especially
around here in Montana, or in several other western US states—you
might have noticed they sometimes just look a little… out 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 cows—ones 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 eating” habit. 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 actinidine—might
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 or “high” feelings
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 true—it’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]
