A Journal of Philosophy, Applied to the Real World

Consistent Vegetarianism and the Suffering of Wild Animals

University of Oxford

Oxford Uehiro Prize in practical Ethics 2015-16


Ethical consequentialist vegetarians believe that farmed animals have lives that are worse than non-existence. In this paper, I sketch out an argument that wild animals have worse lives than farmed animals, and that consistent vegetarians should therefore reduce the number of wild animals as a top priority. I consider objections to the argument, and discuss which courses of action are open to those who accept the argument.


Many consequentialists are vegetarian because they care about the harm done to farmed animals. Some consequentialists may be vegetarian because of environmental concerns, and others for non-consequentialist reasons, but these are not my main focus here. More precisely then, ethical consequentialist vegetarians believe that farmed animals have lives so bad they are not worth living, so that it is better for them not to come into existence. Vegetarians reduce the demand for meat, so that farmers will breed fewer animals, preventing the existence of additional animals. If ethical consequentialist vegetarians1 believed that animals have lives that are unpleasant but still better than non-existence, they would focus on reducing harm to these animals without reducing their numbers, for instance by supporting humane slaughter or buying meat from free-range cows.

I will argue that if vegetarians were to apply this principle consistently, the suffering of wild animals would dominate their concerns, and would plausibly lead them to support reducing the number of wild animals, for instance through habitat destruction or sterilisation.

Suffering in nature, and its implications

If animals like free-range cows have lives that are not worth living, almost all wild animals could plausibly be thought to also have lives that are worse than non-existence. Nature is often romanticised as a well-balanced idyll, so this may seem counter-intuitive. But extreme forms of suffering like starvation, dehydration, or being eaten alive by a predator are much more common in wild animals than farm animals. Crocodiles and hyenas disembowel their prey before killing them (Tomasik 2009). In birds, diseases like avian salmonellosis produce excruciating symptoms in the final days of life, such as depression, shivering, loss of appetite, and just before death, blindness, incoordination, staggering, tremor and convulsions (Michigan Department of Natural Resources). While a farmed animal like a free-range cow has to endure some confinement and a premature and potentially painful death (stunning sometimes fails), a wild animal may suffer comparable experiences, such as surviving a cold winter or having to fear predators, while additionally undergoing the aforementioned extreme suffering (Tomasik 2013). Wild animals do experience significant pleasure, for instance when they eat, play, have sex, or engage in other normal physical activity. One reason to suspect that on average this pleasure is outweighed by suffering is that most species use the reproductive strategy of r-selection, which means that the overwhelming majority of their offspring starve or are eaten shortly after birth and only very few reach reproductive age (Horta 2010; Ng 1995). For instance, ‘in her lifetime a lioness might have 20 cubs; a pigeon, 150 chicks; a mouse, 1000 kits’ (Hapgood 1979), the vast majority of which will die before they could have had many pleasurable experiences. Overall, it seems plausible that wild animals have worse lives than, say, free-range cows. If vegetarians think it’s better for the latter not to exist, they must believe the same thing about wild animals.

A second important empirical fact is that wild animals far outnumber farmed animals. Using figures from the FAO, Tomasik estimates that the global livestock population is 24 billion (including 17 billion chicken) (Tomasik 2014). I restrict my count of wild animals to those at least as complex as chicken or small fish, which vegetarians clearly believe do have moral weight. Using studies of animal density in different biomes, Tomasik estimates conservatively that there are at least 6*1010 land birds, 1011 land mammals, and 1013 fish. Animals in each of these categories alone are several times more numerous than livestock.

If wild animals’ well-being is indeed below the threshold for a life worth living, and the above numbers are remotely correct, the scale of wild animal suffering is vast. As Richard Dawkins writes, ‘During the minute it takes me to compose this sentence, thousands of animals are being eaten alive; others are running for their lives, whimpering with fear; others are being slowly devoured from within by rasping parasites; thousands of all kinds are dying of starvation, thirst and disease.’ (Dawkins 1996) If they accept the premises so far, consistent vegetarians should focus on preventing the existence of as many wild animals as possible, since even a small reduction in the global number of wild animals would outweigh the impact of ending all livestock production. For example, they could reduce animal populations by sterilising them, or by destroying highly dense animal habitats such as rainforests. It may even be the case that vegetarians should react to this argument by eating more meat, since feeding livestock requires more surface area for agriculture, and fields contain far fewer wild animals per square kilometre than other biomes such as forests (Matheny and Chan 2005, 585). Of course, to the extent that it is more difficult to reduce wild animal populations than farm animal populations, vegetarians should focus more resources on the latter. But it seems implausible that it would be over a hundred times more difficult to achieve the same proportional reduction, which is what would be needed to reverse my conclusion that wild animal suffering dominates. There could be some simple ways, for instance, for vegetarians to reduce habitat sizes: supporting the construction of large parking lots, or donating to a pro-deforestation lobby. In the final paragraph, I touch upon the issue of how most effectively to reduce wild animal suffering.

Objections in principle

An intuitive response to wild animal suffering can be that cycles of predation and starvation are natural, and therefore they must be neutral morally. But what is natural is not necessarily what is good, for instance, humans will routinely use technology to remove diseases which are natural.

It is important to emphasize that the claim that wild animal suffering is bad does not imply a guilt claim of the form ‘predators are morally guilty’. A lion’s instinct is indeed natural and does not deserve our moral condemnation. However, we can avoid much confusion if we remember to keep separate the concepts of guilt of an agent and wrongness of an action. It is perfectly possible to claim that X is harmful and should be prevented while also holding that the direct cause of X is not a moral agent. The fact that we are so used to thinking about cases of human behaviour, where guilt and wrongness are largely aligned, may partly explain why arguments about wild animal suffering seem counter-intuitive.

Underlying some of these principled arguments is the intuition that harmful acts, like killing livestock, are worse than harmful omissions, like failing to avert wild animal suffering. Consequentialists should reject these intuitions. It is not my goal here to convince non-consequentialists to abandon the act-omission distinction. However, I offer them a thought experiment to suggest that harmful omissions matter at least somewhat. Imagine you see a fire spreading in a forest and, while walking away from the fire, you see an injured fawn: a broken leg prevents her from fleeing. You carry a rifle and could instantly kill the fawn at no cost to yourself, preventing her from the extreme suffering of being burned alive. In this situation, for vegetarians who care about harm to animals, it is clear that it would be immoral to omit to act and allow wild animal suffering to happen. So the general principle that allowing wild animals to suffer is morally neutral cannot hold.

Empirical objections

A second set of counter-arguments are empirical: they concede that consistent vegetarians would be morally obliged to reduce wild animal suffering, but attack various empirical claims made above.

It may be objected that we cannot reduce the number of animals by sterilising them, because as soon as fewer animals are born, more resources (like food and territory) become available, which increases the evolutionary payoff of producing more animals. If we sterilise some deer, there will at first be fewer fawns, so there will be more nuts and berries available, which allows other deer (or other species) to have more offspring, until we are back to the original equilibrium. The existence of such evolutionary pressures towards an equilibrium population seems plausible, but it remains an unsolved empirical question. It may be the case that the population takes several years to reach its equilibrium again, in which case much animal suffering would be averted in the meantime. Regardless, this is only an objection against one particular method for reducing wild animal numbers, and it only tells us that sterilisation would be ineffective, not harmful. If we reject sterilisation on these grounds, habitat destruction, for instance, evidently does reduce animal numbers for the long run.

A frequent objection against intervening in nature is that we are uncertain about the consequences: for instance, culling predators might cause an ecological catastrophe. While our uncertainty is a good reason to do more research in order to reduce it, it is not in principle an argument for inaction. First, we should avoid the misconception that inaction is not uncertain: the consequence of inaction is to maintain the status quo, and the status quo could be causing vastly more (or less) suffering than we currently estimate. Of course, to the extent that we know something about the amount of suffering under the status quo, inaction is less uncertain than intervention. However, this would only be an argument for inaction if we were risk averse about amounts of animal suffering. Such fundamental risk aversion appears both theoretically problematic, and, in a case where the status quo already seems to contain immense suffering, unintuitive.

In order to see if our aversion to intervene may be caused by a bias in favour or the status quo, we can use the reversal test (Bostrom and Ord 2006), an elegant instance of which is provided by the reintroduction of wolves in Scotland, where they had been hunted to extinction in the 1700s (BBC News 2007). If we oppose reintroducing wolves because this would cause their prey to suffer, then we should prima facie support sterilising existing wolf populations. The outcome of inaction in the sterilisation case is similar to the outcome of action in the reintroduction case, and those who oppose both reintroduction and sterilisation should explain what the morally relevant difference is.

The strongest counter-arguments are those trying to show that wild animals’ lives actually are better than non-existence. This is empirically a very uncertain question. How much pain or pleasure animals feel in response to certain stimuli is dependent on facts about their neurology which is not well understood. While we may make some reasonable extrapolation from our human experience (being eaten alive is very painful), animal subjective experience may differ significantly. While animals might experience hedonic adaptation (Shane and Loewensein 1999) to their circumstances, encounters with predators produce lasting psychological damage similar to post-traumatic stress disorder in humans (Zoladz 2008). There is some evidence that domesticated animals are less stressed (Wilcox 2016), but measures of stress hormones may not coincide with animals’ revealed preferences (Dawkins 2004). Clearly, I do not pretend to have solved this difficult question (more research on this neglected topic should be a pressing priority for those who agree that wild animal suffering on a vast scale would be morally catastrophic). However, I note that these considerations should also make us uncertain about the subjective well-being of farmed animals; and I have already offered reasons why wild animals plausibly have worse lives than free-range animals.

Even if wild animals have good lives, reducing suffering may still be a priority

Even if vegetarians still reject this argument, and believe that wild animals’ lives are better than the lives of farm animals, to the extent that they are worth living, this does not imply they should do nothing. They should not reduce animal numbers, but they should still reduce the suffering of existing animals. Because there are so many animals and the suffering they undergo can be so extreme, this consideration would likely still dominate concern about farmed animals. One could vaccinate animals against diseases: rabies has already been eliminated from foxes for human benefit (Freuling 2013). After elephants’ teeth wear out, they are no longer able to chew food and eventually collapse from hunger, after which they may be eaten alive by scavengers and predators. Fitting elephants with artificial dentures, which has already been done on captive animals, would significantly increase their healthspan (Pearce 2015). Or one could cull predator populations by allowing more of them to be hunted.

With this type of intervention, as opposed to interventions reducing the number of wild animals, a possible concern may be that any advantage given to a particular individual by reducing their suffering would increase the suffering of others. For instance, if elephants can eat for longer, more other herbivores will starve; or if we kill predators, their prey will proliferate and their competitors will starve. If we think that ecosystems lie on such a razor-sharp Malthusian equilibrium where all animals are strongly competing for every piece of resource, this objection is plausible. But crucially, if we accept this, then it becomes more plausible that wild animals actually do have lives that are not worth living: if evolution produces so many animals that each can just barely survive, it is likely that they endure much suffering and little pleasure. So it seems like we must either accept that some interventions can reduce extreme wild animal suffering, or concede that animals’ lives are plausibly not worth living.


Some may choose to treat this outlandish conclusion as a reductio against consequentialist ethical vegetarianism (either against the idea that farm animals matter morally or against the belief that we should prevent them from coming into existence). Perhaps vegetarians who still reject the conclusion should increase their confidence that buying free-range meat is a good thing. For those who accept it, the question of how most effectively to reduce wild animal suffering is left open. As I have repeatedly emphasised, we are still very ignorant about many relevant empirical questions, so immediate large-scale intervention will not be very effective. In addition, intervention may have significant backlash effects and reduce sympathy for the anti-speciesist message. The best immediate action is probably to produce more research on wild animal suffering, in order to make future action more likely to be effective.


Allen, Colin & Trestman, Michael. “Animal Consciousness.” In Edward N. Zalta, ed. The Stanford Encyclopaedia of Philosophy (Winter 2009) Web: https://plato.stanford.edu/archives/win2009/entries/consciousness-animal/. Accessed 25 January 2016.

BBC News. “Wild Wolves ‘Good for Ecosystems’”, 31 Jan. 2007. Web: http://news.bbc.co.uk/1/hi/sci/tech/6310211.stm. Accessed 25 Jan. 2016.

Bostrom, Nick, and Toby Ord. “The Reversal Test: Eliminating Status Quo Bias in Applied Ethics.” Ethics 116.4 (2006): 656-679.

Cowen, Tyler. “Policing Nature.” Environmental Ethics 25.2 (2003): 169-182.

Dawkins, M. S. “Using Behaviour to Assess Animal Welfare.” Animal Welfare 13 (2004): S3-S8.

———. Animal Suffering: The Science of Animal Welfare. Springer Science & Business Media, 2012.

Dawkins, Richard. River Out of Eden: A Darwinian View of Life. Basic Books, 1996.

Ebert, Rainer, and Tibor R. Machan. “Innocent Threats and the Moral Problem of Carnivorous Animals.” Journal of Applied Philosophy 29.2 (2012): 146-159.

Freuling, Conrad M., et al. “The Elimination of Fox Rabies from Europe: Determinants of Success and Lessons for the Future.” Philosophical Transactions of the Royal Society B: Biological Sciences 368.1623 (2013): 20120142.

Frederick, Shane, and George Loewenstein. “Hedonic Adaptation.” (1999). In Diener, Ed, Daniel Kahneman, and Norbert Schwarz, eds. Well-being: The Foundations of Hedonic Psychology. Russell Sage Foundation, 1999.

Hapgood, Fred. Why Males Exist: An Inquiry into the Evolution of Sex. Morrow, 1979. Quoted in The Importance of Wild-Animal Suffering, Tomasik, Brian, Foundational Research Institute, 2016. Web: https://foundational-research.org/the-importance-of-wild-animal-suffering. Accessed 25 Jan 2016

Horta, Oscar. “Debunking the Idyllic View of Natural Processes: Population Dynamics and Suffering in the Wild.” Télos 17.1 (2010): 73-88.

Howard-Snyder, Frances. In Edward N. Zalta, ed. “Doing Versus Allowing Harm.” The Stanford Encyclopaedia of Philosophy (Winter 2011) Web: https://stanford.library.sydney.edu.au/archives/win2011/entries/doing-allowing/. Accessed 25 January 2016. /p>

Matheny, Gaverick, and Kai M. A. Chan. “Human Diets and Animal Welfare: The Illogic of the Larder.” Journal of Agricultural and Environmental Ethics 18, no. 6 (December 2005).

Michigan Department of Natural Resources. “Salmonellosis.” Quoted in The Importance of Wild-Animal Suffering, Tomasik, Brian, Foundational Research Institute, 2016. Web: https://foundational-research.org/the-importance-of-wild-animal-suffering. Accessed 25 Jan 2016.

Ng, Yew-Kwang. “Towards Welfare Biology: Evolutionary Economics of Animal Consciousness and Suffering.” Biology and Philosophy 10.3 (1995): 255-285.

Pearce, David. “A Welfare State for Elephants?.” Relations 3.2. November 2015-Wild Animal Suffering and Intervention in Nature: Part II (2015): 153.

Tomasik, Brian. “The Predominance of Wild-Animal Suffering over Happiness: An Open Problem.” Essays on Reducing Suffering (2009): 255-85.

———. “Intention-Based Moral Reactions Distort Intuitions about Wild Animals.” Essays on Reducing Suffering (2013). Web: http://reducing-suffering.org/intention-based-moral-reactions-distort-intuitions-about-wild-animals/. Accessed 12 December 2016.

———. “How Many Wild Animals Are There?.” Essays on Reducing Suffering (2014). Web: http://reducing-suffering.org/how-many-wild-animals-are-there/. Accessed 12 December 2016.

Wilcox, Chritie. “Bambi or Bessie: Are Wild Animals Happier?” Scientific American Blog. N.p., 21 Apr. 2011. Web: https://blogs.scientificamerican.com/guest-blog/bambi-or-bessie-are-wild-animals-happier/. Accessed 20 Jan. 2016.

Zoladz, Phillip R. An Ethologically Relevant Animal Model of Post-Traumatic Stress Disorder: Physiological, Pharmacological and Behavioral Sequelae in Rats Exposed to Predator Stress and Social Instability. Diss. University of South Florida, 2008.

1. Hereafter I drop the qualifiers and use ‘vegetarians’ to mean ‘ethical consequentialist vegetarians’, unless otherwise specified.