We, as emotional beings, place a high value on happiness and joy. Happiness is more than a feeling to us - it’s something we require and strive for. We’re so fixated on happiness that we define the pursuit of it as a right. We seek happiness not only for ourselves and our loved ones, but also for our planet and its creatures.

Sure, campaigns for Animal Liberation take this to the extreme. They believe that all animals "deserve to lead free, natural lives." But extreme animal activists aren’t the only ones who think animal happiness is important. They’re not even the only ones that think animals have some level of right to be free. Many people are against zoos because they feel it’s wrong to keep animals in captivity. I’ve even heard arguments for hunting as an alternative to farming livestock, because at least the wild animals lived happily prior to their death, while the poor cows or chickens suffered because they are never allowed to be free. And let’s be honest: who didn’t watch Free Willy and feel, at least for a moment, that every animal we have ever put in a cage or a tank should be let go?

The core idea behind all of this is the belief that animals in nature are truly happier than animals in captivity, even than domesticated ones. But are they? I mean, really?

Happiness is hard enough to define in people, let alone in an animals. You can’t just ask them how they are feeling. Instead, we tend to qualify happiness in animals as a lack of chronic stress. Stress, unlike happiness, is very easy to measure. You can look for decreases in overall health in just about any kind of creature. You can keep an eye out for neurotic behaviors, and measurements of hormone levels of cortisol, norepinephrine, adrenaline and other "stress" hormones provide a quantified means of measuring stress. Though lack of stress doesn’t guarantee "happiness", it’s the closest we can get.

The idea, in particular, that livestock could be happier than wild animals is a hard thing to grasp, because as people, we can’t imagine being kept simply to be used. The idea of having no control over how we are used by another, even if we’re given everything we want now, seems unbearably cruel - but it’s not the same for animals. Domesticated animals don’t feel stress about the future, because they don’t have an understanding of their future in the same way we do. A cow doesn’t live a more stressed or unhappy life than a dog or a deer because it is destined to be killed for its meat. Cows aren’t upset that they will end up as steaks because, as Michael Pollan phrased it, "in a bovine brain the concept of nonexistence is blissfully absent."

So the real question becomes whether a domesticated or captive animal is more, less, or as happy in the moment as its wild counterpart. There are a few key conditions that are classically thought to lead to a "happy" animal by reducing undue stress. These are the basis for most animal cruelty regulations, including those in the US and UK. They include that animals have the ‘rights’ to:

- Enough food and water

- Comfortable conditions (temperature, etc)

- Expression of normal behavior

Now, the factory farm industry isn’t known for its strict adherence to these standards. But many farms do care for their animals well, and the vast majority of pet owners do, too. Domesticated and other captive animals, by and large, live lives where they are well fed, free of curable diseases, in comfortable conditions where they are able to be themselves, at least to a certain extent.

When it comes to wild animals, though, only the last is guaranteed. They have to struggle to survive on a daily basis, from finding food and water to another individual to mate with. They don’t have the right to comfort, stability, or good health. Moreover, when the ‘expression of normal behavior’ encroaches upon people, whether it be raiding trash cans or attacks, that last one gets thrown out the window, too. By the standards our governments have set, the life of a wild animal is cruelty.

But even still - are they happier? First and foremost, it’s important to realize that not all animals are the same. Domesticated animals are fundamentally different from their wild counterparts: they are not just wild animals that have been raised in captivity; they have undergone evolutionary changes through artificial selection that have altered their bodies, brains and behaviors.

We have no evidence whatsoever that wild animals are, in any way, happier than domesticated ones which are treated well. One of the consequences of domestication is a decrease in stress across the board. Studies have shown that domesticated animals are less stressed to begin with, and freak out less in response to stressful things like unfamiliar habitats or predators. Guinea pigs, for example, have serum epinephrine and norepinephrine concentrations that are four to eight times lower than their wild counterparts, cavies. They also have a reduced response when intentionally stressed by being placed in an unfamiliar cage. Similar results have been found in cats, rats, ducks and even fish. In fact, a decreased stress response compared to wild counterparts has been found in every single domesticated species that has been studied.

It’s more than just how they were raised, too. A similar study raised cavies in captivity for 30 generations and compared their behavior and hormone levels to wild-raised cavies and domesticated guinea pigs. They found that the behavioral differences between domesticated and wild animals held even after 30 generations of captive rearing. Just like before, the wild animals had both a higher basal stress levels and stress responses. Even the captive-raised cavies had higher levels of norepinephrine and epinephrine from the get-go. Furthermore, both the wild and captive-raised cavies showed a markedly higher stress response to an unfamiliar environment than the domesticated guinea pigs.

When we domesticated animals, we forever altered how they respond to their environment. We reduced their sensitivity to things that are otherwise very upsetting to their wild relatives - like interacting with us. The side effect of this is that domesticated animals are predisposed to being happier than their wild counterparts, in spite of captivity.

"To think of domestication as a form of enslavement or even exploitation is to misconstrue the whole relationship, to project a human idea of power onto what is, in fact, an instance of mutualism between species," Pollan explains - and he’s right.

Stress is important for surviving in the wild. Stress tells you you’re in danger, and provides your body with the boost of performance needed to get out of the situation. The attenuated stress response exhibited by domesticated species doesn’t just make them easier to keep happy in captivity, it makes them less fit to live outside of it. The vast majority of domesticated animals wouldn’t survive in the wild, period. As the 19th century philosopher Leslie Stephen put it, "The pig has a stronger interest than anyone in the demand for bacon. If all the world were Jewish, there would be no pigs at all."

Releasing a domesticated animal into the wild isn’t ‘freeing’ it - it’s placing a mostly defenseless creature in an unfamiliar and uninviting habitat that it is simply not equipped to deal with. Whether you want to morally condemn the people who domesticated animals in the first place is up to you, but ‘liberating’ them now simply isn’t in their best interests.

These data also suggest something that might seem a bit radical: if we follow the guidelines of care that provide food, water, comfort, and necessary items for behavioral expression, domesticated animals are not only likely to be as happy as their wild relatives, they’re probably happier. This applies to livestock as much as it does to a guinea pig, in spite of the fact that we raise the livestock solely to be killed and eaten.

But what about captive animals from non-domesticated lineages? Are animals that haven’t undergone the evolutionary changes of domestication happier in the wild?

That’s a much harder question to answer, in part because we don’t have good baselines for wild animals. Until recently, studying stress hormone levels meant drawing blood - which, as you can image, is a stressful event in and of itself for a wild animal. However, newer methods have been developed that can measure the stress hormone levels in scat and urine left by wild animals, so it’s now possible to get an assessment of stress that doesn’t involve capturing the animal first.

What we do know so far is that evidence suggests wild animals can be as happy in captivity as they are in nature, assuming they are treated well. Confinement alone doesn’t mean an animal is automatically worse off. If we give an animal all the good things they would have in the wild (food and water, fellow members of their species, a certain amount of space) and take away that stresses or hurts them (predators, parasites, extreme weather), then it can live just as happily in an enclosure. Zoo animals with proper care and enrichment, for example, have similar hormone profiles, live longer, eat better, and are healthier than their wild counterparts. Why? Because life in the wild is hard. In captivity, it’s easy.

We also know that when we change our care of an animal to try to decrease stress, we succeed. Stress hormone levels drop, for example, when leopards are given a larger enclosure or things to play with. This means we are able to modify our standards of care to ensure that any animals we place in captivity, domesticated or wild, are as happy as they can be.

So overall, are wild animals happier? While there is a lot more science that can be done to answer that question, the answer seems to be: no, not if they’re cared for well in captivity. The more we study animal behaviors, the better we get at figuring out what they need to pursue their own happiness, even when they are not allowed to be ‘free.’

I want to be clear that this doesn’t mean I’m making any moral judgements about zoos, farming, hunting, animal testing, veganism, or anything else this information might apply to. For all of those topics, the suffering or lack thereof during life is only one of many considerations that factors into morality. I have my own personal feelings about these topics, but that’s not the point of this post. I’m just stating the facts about what we know of animal happiness in different conditions - how you interpret their meaning on a broader level is up to you.

However, I will inject a little of my own opinion. I believe this whole idea that wild animals are happier is due to what I call our ‘natural bias’. What do I mean by that? Well, we tend to idealize nature. When we picture the wild world, we see lush forests full of brightly-colored, singing birds, with monkeys swinging from branch to branch. We imagine vast prairies with herds of antelope and zebra grazing peacefully while a pack of lions naps lazily in the shade. Even when we do imagine the more gruesome aspects of the wild, we see them as OK or better than what we do because it’s "natural."

This bias for what is "natural" is pervasive, affecting our judgement on everything from sexual orientation and medical care to farming practices and clothing fibers. But there is nothing inherently better about something being natural, and the idea that something that occurs in nature without us is somehow better than something we have altered or taken part in is a dangerous fallacy (the use of Rotenone by organic farms, a natural but unbelievably awful pesticide that was still usable in Europe until 2009, is a prime example). I love the natural world. I became a biologist because of my passion for all kinds of creatures, and conservation is one of the core tenants of what I do on a daily basis. But while I appreciate and fight for the beauty and brilliance that is our planet, I firmly believe we need to see ourselves as a part of it, not above or below it. We are, after all, "natural," too.

Image of Bambi, via Wikimedia Commons.


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About the Author: Christie Wilcox is a science writer who moonlights as PhD student in Cell and Molecular Biology at the University of Hawaii at Manoa. Follow Christie on her blog, Observations of a Nerd, or on Facebook or Twitter.

The views expressed are those of the author and are not necessarily those of Scientific American.