Animals and the Ethics of War: A Call for an Inclusive Just War Theory

December 8 2022

Josh Milburn (Loughborough University) &
Sara Van Goozen (University of York)

Following the Russian invasion of Ukraine in February 2022, heartrending images of Ukrainian refugees and their companion animals fleeing Russian forces circulated among Western media, and the press covered stories of organisations and individuals traveling into Ukraine to feed or rescue the animals left behind. The impact of war on animals became an issue difficult to ignore.

Companion animals are not the only ones impacted by war. Disturbing stories about harm to Ukraine’s farmed animals appeared, while Ukraine’s zookeepers faced difficult choices about whether to evacuate animals. The war’s impact on wild animals is, currently, unknown.

War has always affected animals. Soldiers have always used animals as transport, guards, and mascots. Armies have always staged battles in places where animals live. And domesticated animals have always felt the brunt when hostilities kill or displace their caregivers. Collectively, though, we’ve overlooked these issues. In the fog of war, we lose sight of animals.

Given the impact that war has on animals, it is surprising that we lack the language to meaningfully discuss the ethical questions that animals in war raise. This is because just war theory – the dominant approach to the ethics of war in the western philosophical tradition – is resolutely anthropocentric. At least, it has been until now.

“In the fog of war, we lose sight of animals”

Just War

Just war theory is a set of tools for assessing when it is right to go to war (typically known by the Latin phrase jus ad bellum), how it is appropriate to behave in war (jus in bello), and related questions. Just war theorists tend to concede that states will wage war and that violence can be legitimate, but aim to reduce the occurrence of unjust wars and unjust behaviour in war. In the words of Michael Walzer, war may be hell, but even ‘in hell, it is possible to be more or less humane, to fight with or without restraint’ – just war theorists address ‘how this can be so’.

It is fundamentally a philosophical theory, but one recognised as deeply important by international humanitarian lawyers (as it is the foundation of the international laws of war, such as the Hague Conventions, the Geneva Conventions, and the UN Charter) and militaries themselves (who use it to assess their activities).

International humanitarian lawyers have started to explore how existing laws protect animals. Just last month, Cambridge University Press published Anne Peters, Jérôme de Hemptinne, and Robert Kolb’s pathbreaking Animals in the International Law of Armed Conflict. And, for a variety of reasons, militaries themselves grapple with questions about the treatment of animals. Many navies, for example, have policies to limit the impact of sonar on whales and dolphins. But just war theory lags behind. 

An inclusive theory?

What would a more inclusive, more humane, just war theory look like? For one, it’d tell us if (and when) harm to animals could constitute a just cause for war, and more broadly how to include animals in considerations of jus ad bellum. It’d also tell us how to factor animals into questions of fighting justly. It would tell us, for instance, when it was legitimate for militaries to use animals as tools of war, and when soldiers on the battlefield might legitimately target animals.

But the most pressing questions – we’ve argued – concern ‘proportionality’ and ‘necessity’. These are issues for both jus ad bellum and jus in bello. They are principles about reducing harm. That includes harm to targets themselves (e.g., enemy combatants). But it also includes foreseen but unintended ‘collateral damage’, such as harm to civilians.

Roughly, a military action is ‘proportionate’ if the harm it causes is lower than the harm it would prevent. So perhaps it’s proportionate for a sniper to fire on a militant in a block of flats, given the harm that the militant could do to patrolling soldiers, even though this damages civilian property and kills the militant. On the other hand, bombing the block would kill civilians within as well as the militant, and so would be disproportionate.

Meanwhile, an action is ‘necessary’ (roughly) when there is no less harmful route to the same goal. So even if the sniper’s actions above are proportionate, they may be unnecessary if, for example, soldiers were able to force the militant to surrender without loss of life.

But where do animals fit into these considerations? Well, on an anthropocentric understanding of just war, militaries will sometimes have to consider animals as civilian property. For example, it would be easier to justify bombing a barn containing militants and scrap metal than a barn containing militants and cattle, but that’s because cattle are worth more than scrap metal. It might be easier to justify bombing militants hidden in a barn with cattle than militants hidden in a barn with expensive farm machinery, say.

We admit that things aren’t quite that simple. For example, there are norms of war protecting culturally significant objects, as well as those things important to preserve civilian lives. Both might justify relatively stringent protections for cattle in the case above. But these are not protections for the animals’ own sakes.

We think that animals should be protected for their own sakes. We argue that militaries should take the interests of humans and animals into account when calculating whether an action is necessary and proportionate.

This doesn’t mean that countries can’t wage war because refugees might abandon dogs, or soldiers can’t fire on enemies in case they hit birds. But it does give militaries reason to reflect on whether their military goals are worth the harm they’ll cause. And it certainly gives them reason to reflect on whether there may be less harmful routes towards their goals.

Some of the answers this reflection will reveal won’t be surprising. For example, we know that chemical, biological, and nuclear weapons are bad for animals, but we know they’re bad for humans, too. Ethicists and lawyers already, rightly, condemn these methods of waging war.

Other times, though, the answers that an inclusive account of just war offers may be quite different to those offered by an anthropocentric account. While we should be worried when combat takes place in areas with high civilian populations, we should also be worried when combat takes place in areas with high animal populations.

And sometimes taking animals seriously will require making difficult trade-offs. Just war theory already obliges soldiers to put themselves at slightly greater risk to significantly reduce risk to civilians. Perhaps they should also be ready to shoulder increased risk when doing so will significantly reduce risk to animals. In normal circumstances, soldiers shouldn’t take cover in hospitals. Maybe they shouldn’t take cover in veterinary centres, either, even when this might mean putting themselves in danger.

“War may be hell, but even ‘in hell, it is possible to be more or less humane, to fight with or without restraints” – Michael Walzer

But it’s one thing to say that animals’ interests count. It’s another to say how much they count. Some people might want to say that animals’ interests count for less than humans’ interests. Others might want to say that all animals are equal, and counting a nonhuman animal’s interest as less just because it belongs to a nonhuman animal is unjustified discrimination.

We think the first view is, partially, right because, often, animals’ interests aren’t as strong as humans’ interests. But we think the second view is also partially right because the strength of interests isn’t a matter of mere species membership – it’s a matter of reflecting on how much we can harm and benefit particular individuals.

Crucially, human deaths are generally much more morally weighty than animal deaths. If a soldier faces a tragic situation in which one of a dog or a human should die, we think that, in almost all circumstances, the soldier should act so that the dog dies. This is because a human’s death is much worse for the human than the dog’s death is for the dog.

Humans and dogs have markedly different psychologies. For example, humans typically have a range of sophisticated plans for their future life – achievements in their careers, families, hobbies, and more. Dogs’ plans, on the other hand, are comparatively basic. So humans usually lose much in death that dogs do not. This isn’t to deny that death is usually very bad for dogs. It’s just to say that it’s not usually as bad as death is for humans. In tragic situations, we must be prepared to make these calls. And war always involves tragic situations.

Humans and animals are equal, on our view – but respecting that equality does not mean that soldiers must treat humans and animals in the same way.


War is bad for animals, yet the predominant approach to the ethics of war, just war theory, remains anthropocentric. We believe that this is a serious oversight, and that now is the time to develop an inclusive just war theory. War will always be regrettable – but, with good will and a little thought, it can be less awful.

1.  Michael Walzer, Just and Unjust Wars (4th edn, Basic Books 2006) 33.
2.  Sarah J. Dolman, Caroline R. Weir, and Michael Jasny, ‘Comparative Review of Marine Mammal Guidance Implemented During Naval Exercises’ (2009) 58 Marine Pollution Bulletin 465.
3. Josh Milburn and Sara van Goozen, ‘Counting Animals in War’ (2021) 47 Social Theory and Practice 657.