Humans are the only species on Earth known to voluntarily consume ethanol. The vast majority of other species have evolved an avoidance for what is essentially a biological poison. Drunk animals are more likely to die and therefore less likely to reproduce, so a trend towards sobriety echoes down the ages in most species. Except us. We will not only go to great lengths to obtain alcohol—even when it is illegal—but we will also consume so much of it we can become ill or die. Why?

It’s Chemical

For most people, drinking small to moderate amounts of alcohol is a pleasurable experience. The pleasure we humans derive from drinking is thought to be due to the effect of alcohol on the brain. A 2009 study conducted in rats found small to medium amounts of alcohol stimulate the release of endorphins—brain “feel good” chemicals. The mechanism is thought to be the same in humans and could be responsible for the slight euphoria many people experience after drinking. Interestingly, the high doses of alcohol were not associated with a greater release of these feel good chemicals.

As many studies can attest, humans will do all sorts of crazy crap to feel good, especially if we can get away with it without being eaten by a predator. Seeing as we are on the top of the food chain essentially and can rely on fellow humans to help us when we are impaired, the potential evolutionary costs of drinking are mitigated for our species. Hence frat parties.

It’s Social Bonding

Alcohol is not referred to as a “social lubricant” for nothing. The consumption of alcohol is known to decrease anxiety and to lower inhibitions in humans, leading sometimes to easier and more enjoyable social interactions. Anecdotally, this is most certainly the case at holiday dinners with otherwise barely tolerable family members. Many important human celebratory events frequently involve alcohol: weddings, birthday parties, holiday parties. Culturally, social drinking is highly acceptable and encouraged—solitary drinking however, is not. Alcohol consumption by humans is closely tied to the fact we are social species.

The use of alcohol in social bonding situations is heavily influenced by culture, even how people behave when drunk is culturally determined and varies from place to place. There is social significance even, to the type of alcohol consumed, it communicates social status information. For example: wine = higher class, educated consumer. Pabst Blue Ribbon = lower class, less educated or ironical hipster (depending on context).

The socializing aspect of drinking alcohol is perhaps the reason for its enduring persistence across most human cultures and most human times—even in the face of its potentially negative biological effects (but perhaps positive theological effects e.g. holding onto the toilet praying you will never drink again if you will stop puking).

It’s a Hobby

Generally speaking, the consumption of alcohol is not considered a hobby unless you happen to be a wine or beer connoisseur. Wine drinking and collecting has become a very popular pastime in the U.S., and a similar situation is occurring with craft beer. There is entire culture and product market surrounding these drinking related hobbies (especially with wine). In addition to the hobby of drinking alcohol, there is a huge hobby related industry for making it at home, both beer and wine. A significant aspect of both types of alcohol related hobbies (the collecting/consuming and the making) is also social as evidenced by the many beer and wine festivals held around the country each year.