Why humans kill animals – Part 3

ABOVE: The rufous hare-wallaby was pushed to the brink of extinction. Photo: Australian Wildlife Conservancy.

Delving into and discussing the final five reasons

Killing animals has been a ubiquitous human behaviour throughout history, yet it is becoming increasingly controversial and criticised in some parts of contemporary human society.

Over a three-part series, researchers from around the globe review 10 primary reasons why humans kill animals, discuss the necessity or not of these forms of killing and describe the global ecological context for human killing of animals.

The article can be viewed in its entirety at sciencedirect.com/science/article/pii/S0048969723039062

Humans historically and currently kill animals either directly or indirectly for the following reasons:

• Wild harvest or food acquisition
• Human health and safety
• Agriculture and aquaculture
• Urbanisation and industrialisation
• Invasive, overabundant or nuisance wildlife control
• Threatened species conservation
• Recreation, sport or entertainment
• Mercy or compassion
• Cultural and religious practice
• Research, education and testing.

 

The final five of those reasons are discussed here.

6. Threatened species conservation

Killing one animal to save another more threatened or less abundant animal is largely an altruistic act, though humans might derive some aesthetic benefit from retaining only native species in a given location (see reason 5 in last month’s issue).

Killing animals (either native or non-native) to protect threatened species is also common across continents.

Non-native examples include killing feral cats, brushtail possums or stoats to protect small mammals and ground-nesting birds in Australia and New Zealand, killing grey squirrels to protect red squirrels in Europe, killing camels to protect the water sources used by native animals in Australia, or killing rodents to protect seabirds or endangered endemic rodents on oceanic islands.

Native examples include killing dingoes to protect rufous hare-wallabies in Australia, or killing barred owls to protect spotted owls in North America.

Many examples of this form of killing involve killing predators to alleviate their impacts on prey.

Additional examples include killing common herbivores to alleviate competition with threatened herbivores or killing herbivores to reduce their impacts on threatened plants.

Population control (that is, killing) of various carnivore and herbivore species is also required in smaller protected areas to ensure that overutilisation of resources (either plants or animals) by one or more species does not cause the death and decline of others.

This type of animal killing may be a necessary temporary solution when abundant vertebrates pose an immediate threat to the survival of a rare species, given that killing relatively few animals in the short term can reduce the overall numbers of animals killed in the long term.

However, the repeated killing of common animals to save endangered ones may produce several adverse outcomes, including the high cost of population control, ecosystem changes that favour increases of other harmful species, or increases of diseases harmful to the endangered species.

Habitat rehabilitation and restoration programs may be better solutions to problems caused by abundant native animal species because community and ecosystem degradation are the ultimate causal factors responsible for some species becoming rare and others becoming abundant.

These solutions are long-term, biologically sound and involve little direct human intervention into ecosystem processes.

Thus, humans do not need to kill animals to save other animals, but abstaining would knowingly magnify the number of individual animals killed and condemn entire species to extinction in some cases.

7. Recreation, sport, entertainment

Recreational hunting and fishing, or killing animals for sport or entertainment, is a particularly contentious form of animal killing by humans.

This practice is also distinguished from other types of animal killing by its motivation.

For example, recreational hunting and fishing do not always result in consuming the animal, but when it does, this behaviour might be better classified as wild harvest (see reason 1).

Here, we define recreational killing as being purely for entertainment, sport or pleasure, including collecting trophies, achieving personal goals (for example, catching a large fish), facilitating gambling or keeping pet animals.

This type of animal killing by humans evolved out of necessity to acquire food and protect life or property (see reasons 1-4), and the behaviour further developed as a rite of passage, or a demonstration of personal skill or work ethic also associated with mate acquisition.

However, continued cultural evolution in many human societies has meant that recreational hunting is now undertaken as a largely symbolic gesture or pleasurable use of time.

Alternatively, recreational hunting might be interpreted as a righteously defiant – that is, defiant of moral arguments that discourage recreational hunting – ritual resembling animal sacrifice in the religious sphere (see also reason 9).

There are countless examples of recreational killing by humans – virtually any animal with horns, large teeth or tusks, attractive fur or feathers has been or is still hunted for sport.

High-profile examples include red fox hunting in England and lion hunting in southern Africa.

Lesser-known examples include live-baiting with rabbits to train greyhound dogs.

Many wild animals are also killed to feed the billions of pet animals (that is, cats and dogs) kept by humans for pleasure.

For example, 13.5 percent of the total 39 million tonnes of wildcaught fish is used to support the pet food industry.

Cock, dog and bull fighting are other forms of recreational animal killing and, in the case of bull fighting, is also a legally protected cultural heritage activity (see reason 9).

Death of the animal is the intended goal or at least an unavoidable outcome of recreational killing in many cases (as an example, to acquire a trophy).

Yet some forms of such recreation do not require killing, including the catch-and-release practices common to anglers or the type of no-kill trophy hunting proposed by Cove.

These practices may cause some harm to animals, which might inadvertently die on occasion, but they do not necessarily demand animal killing.

Such non-consumptive activities still require skills used in recreational hunting, such as wildlife photography, bird watching or snow tracking, and might therefore be as personally rewarding as killing the animal in some cases.

Many forms of recreational killing may be avoidable.

However, without alternative revenue streams, cessation of these practices will indirectly result in the death of many animals, given that wildlife conservation efforts in many parts of the world are directly funded through recreational killing activities.

Recreational hunting may also contribute to wildlife conservation through the suppression of overabundant game species.

8. Mercy or compassion

Humans frequently kill animals out of mercy or for compassionate reasons.

For example, humans will often have a beloved pet dog or cat killed by a veterinarian (that is, euthanised) to avoid continued suffering when the pet becomes old or ill.

Various wildlife species injured in predation attempts, road collisions or other accidents are also euthanised to prevent the inevitable suffering and likely death that will occur if the animal is left, in the vain hope it will later recover.

Euthanasia may also be appropriate for wildlife casualties that are a danger to other animals or humans.

In some circumstances involving a flock, herd or group problem (that is, a disease outbreak), euthanasia of a small number of ill animals may also be required to provide a diagnosis, allowing appropriate treatment of the remainder of the flock, herd or group.

Healthy animals in zoos or fenced reserves might also be killed because they are surplus to requirements (for example, genetically similar individuals might lead to inbreeding and compromise breeding programs), or to prevent them from being killed by other animals or ecological processes, given a lack of space to accommodate them (see also reason 6).

A variety of other, more nuanced reasons might further necessitate mercy killing, especially in veterinary care settings.

Unlike wild harvest (reason 1), agriculture (reason 3) or urbanisation (reason 4), where killing is unavoidable, compassionate killing or mercy killing is easily avoidable by ‘doing nothing’.

Debilitated animals might even be kept intentionally alive with palliative care to facilitate the generation of induced pluripotent stem cells, which are useful for developing therapeutic applications for captive animals that suffer from degenerative diseases or for preserving the genomes of individuals for later use in genetic rescue efforts (see also reason 6).

However, suffering animals with a poor prognosis for survival are typically euthanised rather than left to die more slowly because inaction causes preventable harm to animals, and failure to kill the animal can be a punishable breach of animal welfare law in some countries.

This interplay between animal ethics and animal welfare means that in cases of mercy killing, humans must choose to shorten suffering and kill the animal or avoid killing the animal and prolong suffering.

The moral acceptability of mercy or compassionate killing is grounded in the understanding that killing the animal results in less harm than allowing the animal to live – a ‘good death’ is seen as a more desirable alternative to a ‘bad life’ when a ‘good life’ is not possible.

9. Cultural and religious practice

Buddhism, Islam, Hinduism, Judaism, and Christianity – indeed almost all the world’s major religions and cultures permit the killing of various animals for the purpose of eating meat (reasons 1 and 3).

Cultural practices around the world also sanction animal killing for non-consumptive purposes, including religious animal sacrifices to a deity or god.

Animals sacrificed to a deity may or may not be subsequently eaten.

Though ‘life is dear to all’ in Buddhism, where the precept ‘one should not kill nor cause others to kill’ is sometimes applied through strict vegetarianism, meat-eating is still commonplace in most Buddhist societies.

Other branches of Buddhism permit what might be described as ‘scavenging’ when the meat is available or offered rather than intentionally killed

The sacrifice of sheep, goats, cows, camels and sometimes yaks and banteng is commonly practiced in Islamic communities around the world in association with the celebration of the Eid al-Adha (that is, ‘feast of sacrifice’, ‘great feast’, ‘sacrifice feast’, or ‘goat feast’) during the Hajj or pilgrimage.

In Indonesia alone, approximately 800,000 goats were sacrificed during the festival in 2014.

About 2.5 million sheep, cows and goats are sacrificed during this festival in Turkey each year, and about 10 million in Pakistan.

Muslims also perform animal sacrifices on other religious occasions.

Animal sacrifice is also widespread in polytheistic Hindu cultures, where various traditions sacrifice animals to a variety of deities, especially in India and Nepal, where mainly goats, buffaloes and chickens are killed.

Pacific Island cultures also sacrifice animals.

For example, chickens or goats are sacrificed to wanamo (a half-man half-dog spirit that protects the forest) in the Bundi region of Papua New Guinea to secure safe passage through the forest for people that do not belong to the local indigenous tribe.

Animal sacrifice is also common in many African cultures, such as the Isese or Yoruba religion found in West Africa and the Afro-American religions of the Caribbean.

Animal sacrifices were practiced extensively in ancient Jewish, Christian and other monotheistic cultures of the Near East and beyond in Europe and North Africa.

For ancient Jews and Christians, the practice was originally designed to teach about the future sacrifice of the Messiah or Jesus Christ, which then understandably ceased following Jesus’ crucifixion circa 33 CE, when the sacrament or communion (that is, broken bread and wine) was instead instituted to remember Jesus’ sacrifice.

A small number of contemporary Christian denominations in Europe, northern Africa and Mexico still practice a restricted form of animal sacrifice today, killing sheep, chickens or pigeons.

With a history deeply rooted in Judeo-Christian values, most contemporary western cultures do not exhibit animal sacrifice traditions.

Nevertheless, landmark cases brought to the US Supreme Court may permit the practice of ritual animal killing in the US under their constitutional provision of religious freedom – a freedom not supported in Europe.

These examples illustrate the widespread use of animal sacrifice in ancient and modern cultures in all areas of the world and the diverse expression of the practice across different communities.

However, animals are also ritually killed for reasons other than worshipping a deity.

For many, the animal sacrifice is itself constitutive of interspecies kin relations, and the spectacular act of violence at the heart of the sacrifice (as an example, the beheading of the sacrificial animal) is crucial to the constitution of kin solidarity between the human sacrificer and animal victim.

Not all cultural killing of animals is for religious reasons or involves sacrifice.

Feasts, where special foods such as ‘the fatted calf’ or unusual quantities of food are served, can be for socio-political purposes without sacrifice but accompanied by rituals associated with the killing of the animals to serve at the feast.

Exotic cooked flesh can be used to welcome or impress guests, establish or maintain prestige, power or face, or accompany initiations into a society.

Gatherings of people to benefit from super-abundances of food, such as migratory or seasonally abundant animals (for example fish migrations, see also reason 1), are often culturally linked to phenological signals and associated ceremonies.

As examples, ceremonies of food availability, harvesting and use prescriptions were, and are, ritually enacted and celebrated by First Nations peoples in Canada and Australia, and bat harvesting festivals are annually celebrated in northeast India.

It might be argued that humans do not need to kill animals for purely cultural or religious reasons, and there are indeed some noteworthy examples of rapid cultural change to avoid animal killing.

However, we suspect that many people will still feel so deeply about the issue that it could be described as a need, and denigration or suppression of those religious and cultural needs might be considered bigotry, epistemicide or cultural imperialism.

Expression of the very idea that proper or more developed religions are superior to primitive barbaric religions is typically divisive, racist and deeply rooted in colonialism.

Though the practice of animal sacrifice will remain subject to criticism by some people, it is likely to continue except where it is prohibited by law.

Thus, many cultural and religious practices will continue to require the killing of animals and cannot be easily substituted with practices that do not require animal killing.

10. Research, education and testing

Killing animals for research, education and testing purposes is treated separately here because of its unique reasoning.

However, it might also be thought of as an extension to, or component of, many of the other preceding reasons for animal killing by humans (reasons 1-9), given that animal research is often conducted to support our understanding and implementation of those other reasons.

Animals are used in scientific and medical research and education to understand a whole range of questions relating to how human and animal bodies work, what causes diseases in humans and animals, or attempts to develop therapeutic and cosmetic treatments that are safe and effective.

Many, if not most, of the remarkable innovations in our medical understanding and treatment of contemporary human maladies have been at least partly derived from research using animals.

The use of animals for research, education and testing is typically highly regulated to ensure such use is justified on ethical and welfare grounds.

Millions of animals are used each year in research and education (for example dissection, vivisection and veterinary training).

However, adherence to Russell and Burch’s ‘Three Rs’ principle – replacement, reduction and refinement – is now a requirement of most, if not all, legislated and self-regulated national surveillance systems to ensure this use of animals is justified.

The replacement of animals in research has occurred mainly through improvements in techniques, which enable scientists to look for mechanisms of action at the cellular and molecular levels rather than using a ‘whole animal’ approach.

Most national systems of animal research oversight also require reductions in the use of animals where possible, directing that animals should only be used when no other method is available to meet the scientific aims of the study.

The refinement of techniques has resulted in less harm and fewer animal deaths in experimental procedures.

Refinement not only improves the lives of research animals but it can also improve the quality of the science.

One obvious way to improve animal welfare while using animals for research or education purposes is to create an environment that meets the animals’ specific needs.

To this end, Mellor and Reid developed the ‘Five Domains Model’ – originally based on the United Kingdom Farm Animal Welfare Council’s ‘Five Freedoms’ – to assist in identifying welfare impacts under the following domains: nutrition, environment, health, behaviour and mental state.

While the implementation of Russell and Burch’s ‘Three Rs’ principle and Mellor and Reid’s ‘Five Domains Model’ have contributed enormously to the responsible use of animals in scientific research, the use and killing of animals for research and education cannot be easily eliminated outright.

This is partly because animal experimentation is often intended to identify ways to reduce harm to animals.

For example, the effective development of mammal trapping devices used by researchers and trappers involves the implementation of stepwise protocols to minimise pain and suffering and ensures a thorough assessment of traps with a minimum number of animals.

Without such state-of-the-art research protocols and ongoing refinement of techniques, traps used in the field may cause otherwise avoidable pain, suffering and death to millions of animals.

Humans do not need to kill animals for research and education purposes, though refraining from this endeavour will undermine our ability to improve animal welfare and minimise animal killing in the future.

For example, the animal welfare impacts of agricultural killing practices (reason 3) may not improve if we cease researching ways to reduce harm to killed animals, or the harms associated with threatened species conservation efforts (reason 6) may not improve if we cease researching ways to increase reintroduction success.

In the absence of a universal ethic for animal experimentation, concerned scientists and non-scientists alike have plotted different courses of action, while recognising that animal researchers have a role to play as moral stewards of their research animal subjects.

Many medical schools have eliminated their live-animal labs or have reduced the number of healthy animals used for surgical practice and experimental procedures.

Alternatives to the use of live or dead animals, such as interactive three-dimensional computer models, video footage and life-size plastic models, can be as effective as traditional methods in some cases.

In contemporary contexts, the scientific community and the public need to integrate critical thinking with the scientific method to continually identify necessary and unnecessary animal-based studies, which is presently achieved and managed through various national codes of practice.

Animal researchers and educators must also ensure that published research involving animals meets the highest standards for the use and treatment of animals.

Conclusions

Killing animals occurs in multiple ways for multiple reasons and, though some forms of killing are not essential for human existence (for example, recreational hunting and mercy killing), the overall necessity of animal killing is an unavoidable ecological reality.

Animal killing by humans is also a behaviour consistent with our predatory and competitive ecological roles within the global food web.

We invite others to build on the discussion we have initiated here, and encourage respectful comment and further discussion.

Ben Allen
University of Southern Queensland