One Christmas Eve many years ago, I stayed in Prague and cooked a big meal with friends. The food was subsidized by various bottles of wine, liquor, and clear stuff in bottles conspicuously void of label or descriptive promises. Late into the evening, as two of us watched Christmas Vacation as per Christmas ritual tradition 7761/24, I noticed that my cat seemed utterly fascinated with my wine glass. I watched. She was pressing her paw into the remnants of red wine at the bottom of the glass and licking her paws clean. Really clean. I noted this down for future reference and to tell my vet.
Though we got a kick out of it, it shouldn’t have been so surprising. Animals have a long relationship with alcohol. Oh sure, there are cases throughout history of drinking animals. Like Wojtek the Syrian brown bear who became a soldier in the 22nd Artillery Supply Company in the Polish Army during World War II. He fought in the Battle of Monte Cassino and developed a taste for beers, given his military service. Likewise, beers and bears were often coupled at saloons in the old west. Because what better way to wile away your off-hours than to wrestle a bear who’s been drinking? I think it’s a Hemingway book.
But even today drinking – and even drunk – animals are an everyday reality. An evidently common sight in autumn in Sweden are drunken elk stuck in trees. They get into that fix because they are trying to reach the fermenting apples which made them drunk in the first place. Fruit bats also don’t mind a few pops of ethanol-rich fermenting fruit (hence their name). Scientists even believe that they have developed a stronger resistance to alcohol to keep from getting too tipsy. You know, being drunk is great when you can lie on your couch, eat pizza, and watch Netflix, but when you have to fly and you are surrounded by predators who want to eat you, you might want to keep your head a bit. Evolutionarily, it’s just smarter. In fact, one strategy used to catch invasive moths and flies is getting them drunk in beer. This way they stop eating crops and go to the McDonalds down the road or just pass out in front of the tube light.
The pen-tailed treeshrew seems to have one of the animal kingdom’s higher tolerances to booze. Which explains why the pen-tailed treeshrew is always the other animals’ designated driver. Hamsters too seem to be pretty good at warding off drunkenness. When researchers gave zebrafish alcohol (presumably through a straw?) they found they became more reckless, ignoring a robot version of their main predator – the heron. This is similar to when your mild-mannered accountant friend throws an elbow at a rugby player at the pub after a few beers. Neither are likely to survive long.
But some of the drunkest animals on earth – besides the ten-toed homo sapiens – are our relative primates. They act like us too. Macaques who live alone seem to drink more than those with a family unit or support system. They also have a tendency to sway, fall, and puke. Give that macaque a few episodes of Scrubs and a frozen pizza and you have just summarized my 20s … and maybe my 30s. Vervet monkeys on some Caribbean islands steal drinks at bars. These guys have been driven out of the forests by a decline in their favorite fruit source. They invaded the sugar cane fields, which sometimes ferment. Having developed a taste for fruity fermented drinks, they go after tourists’ fruity cocktails and have become something like mascot nuisances to vacationers.
The reason for all of this is ethanol. We humans find it in rum and whiskey, but abundant amounts of ethanol have existed in every Earth ecosystem for over 100 million years. This has given the animal world a lot of time to get used to sip – or rather nibble – on it.
The drunken monkey hypothesis suggests that this is one reason we humans love alcohol so much. The idea is that for tens of millions of years, our primate forefathers would sniff out the ripening fruit in areas scarce with food. Ethanol is a light molecule which would be easy to smell through wind. This would have been a beneficial attraction, as it meant more calories – riper fruit is denser in calories and more developed sugars. This all meant more energy. Our ape ancestors were able to digest this riper fruit better than the smaller monkeys who ate the unripe fruit in the trees above. This is further supported by science, which has identified a mutation in an alcohol-digesting enzyme from around 10 million years ago – right around the time our pre-human ape grandparents came out of the trees to start looking for food on the ground.
So, we survived because of booze. The downside – if that’s how you want to see it – is that this led to descendants who abuse this biological imperative and gorge on that ethanol until they’re incoherent, aggressive, and drawn towards stupid decisions (see: human, nature of). So the next time you make a bad decision or send a text message of ill-choice when you’ve had a few too many, blame our drunken monkey ancestors.
As for my cat, after a few paws of the grape, she started a fight with one of my guests, jumped onto the table and stole some olives. Then she puked on my kitchen floor and spent the rest of the night rubbing her face against my head and telling me how much she loved me. She spent Christmas morning half under covers and in the afternoon tried with all her linguistic gifts to pronounce ibuprofen.
