Is killing animals wrong if they don’t understand death?

The objection

“Animals live in the moment. They don’t anticipate death the way we do, so they don’t suffer the dread of it. A quick kill harms them far less than it would harm a person.”

The answer

The objection takes three steps: animals don’t understand death, so dying doesn’t hurt them, so a death they don’t see coming harms them far less than it would harm a person. The first step is shakier than it sounds, the second wouldn’t follow even if the first held, and even the strongest case for the third leaves the animal harmed.

Do animals understand death?

Some animals probably grasp death in a basic way, though researchers disagree about how many, and the evidence still comes mostly from chance observations in the wild [1]. Scientists who study how animals respond to their dead have recorded birds and mammals carrying, grooming, inspecting and attacking corpses [1]. Most of them treat a concept of death as rare outside humans, but the philosopher Susana Monsó and the comparative-cognition researcher Antonio Osuna-Mascaró argued in 2021 that it needs only the recognition that a dead body has stopped working for good, which many species are equipped to learn, so it is probably common in nature [1]. Their minimal concept leaves out the harder idea that you yourself will one day die [1], so the objection may be right that animals don’t dread their own deaths. It doesn’t follow that dying is painless for them, or harmless.

Does an animal have to understand death to suffer as it dies?

An animal needs no idea of death to feel pain, fear or breathlessness, and the commonest way of stunning pigs for slaughter in several countries causes all three. In a 2024 survey of every slaughterhouse in England and Wales, 90% of pigs were stunned with high-concentration carbon dioxide, a government figure [2]. Europe’s food-safety authority, EFSA, found in 2020 that the gas is “highly aversive” and causes pain, fear and respiratory distress [3]. In 2025 the UK government’s Animal Welfare Committee described conscious pigs vocalising, hyperventilating and trying to escape before they lose consciousness, which takes 21 to 60 seconds in the few published studies, and recommended a ban [4]. Australia’s pig industry body, Australian Pork Limited, estimates that about 85% of the country’s pigs are processed at seven export abattoirs that use the gas (2024) [5], and Ireland’s agriculture minister said in a written answer to the Dáil in June 2026 that most Irish pigs are stunned with it [6]. Footage that the Australian animal-protection charity Farm Transparency Project filmed in 2023 at a slaughterhouse in South Australia shows a sow collapsing and struggling to breathe as she is lowered into the gas [10].

The fear starts before any stunning, with the noise, the unfamiliar pens, people and pigs, and the handling, all of which EFSA lists as hazards for pigs while they are fully conscious. EFSA also found that electrical stunning, which knocks a pig out at once, needs restraint that may add pain and fear, and that driving pigs into single file for it causes fear and pain of its own [3].

Would a painless death still harm an animal?

A painless death would still harm an animal on the account philosophers most often give of why death is bad for whoever dies. Epicurus argued that it isn’t, and the usual reply, going back to Thomas Nagel’s 1970 essay “Death”, is that it harms by deprivation: it makes a life as a whole worse than it would have been by cutting it short and taking away the good life still to come, even for someone who never experiences dying [7]. Nothing in that requires the victim to see death coming, and “they won’t know” would excuse killing a sleeping person just as well. Some philosophers grant part of the objection’s comparison: in Jeff McMahan’s time-relative interest account, the good future that death takes away still counts, but it is weighed by how strongly the victim is psychologically connected to its future self, so a being with fewer plans or expectations for its future loses less [11]. How far animals have such plans or expectations is still debated [11]. In farming, the life cut short has often barely begun: a fast-growing broiler chicken is normally slaughtered at around 37 days old, well before it reaches sexual maturity (EFSA, 2023) [8], and under rules still in force in Great Britain even a chicken sold as free-range can be slaughtered at 56 days [9].