Can the slaughter of pigs in blood spatter research be justified as a necessary evil?

I wrote this essay in late-2015 – my first serious attempt at applied philosophy – and I (tentatively) still agree with its conclusions!

In this paper, I shall argue that the decision to authorise a blood spatter experiment using live pigs was unjustified as it is an unnecessary and unscientific method of research. The notion of necessity that I shall use in this essay refers to the requirement of an act to occur on the basis of there being no suitable alternative, assuming that the ends justify the means. I shall evaluate the moral value of animals comparative to humans in an attempt to rationalise their perceived inferiority. I shall also investigate possible alternatives to live pigs that should have been considered before authorising the experiment. Furthermore, I shall assess the accuracy of using pig skulls to simulate the blood spatter patterns of human’s skulls, denoting anatomical differences that would render the experiment inconclusive. After having established the study’s use of pigs as unnecessary, I shall present a recommendation suggesting an improvement to the approval process of applications for research involving animals. This recommendation could be used to prevent unjustifiable uses of animals in research, such as our case study.

In our current research climate, it is common practice to use animals as tools to collect data. Acts that would be considered barbarous, cruel and illegal under regular circumstances with non-laboratory animals are permitted and seen as ‘necessary evils’ in order to further scientific development and understanding. The recent approval mandating the slaughter of pigs in cranial blood spatter research serves as a good example of this. In the experiment, approved by the University of Otago Animal Ethics Committee, five pigs were shot in the head to simulate the cranial blood spatter that might occur in humans under similar conditions. In preparation for the experiment, each pig was sedated to induce a state of immobility. It is dubious as to the extent that the sedatives were effective as two of the pigs experienced post-shooting bodily spasms, indicating that they may have experienced pain.

Calculating moral value for animals is – and always will be – a controversial topic. For instance, some hold that it is human dignity that distinguishes ourselves from other species, and justifies our methods of animal exploitation (Talbolt, 2012). This method of differentiation would have likely been used in our case study; the notion that pigs are intrinsically different and ‘lacking’ comparative to humans justifying our superiority over them. If this is true, we need to specify what exactly constitutes our ‘uniqueness’. Factors such as “sentience, rationality or moral agency” (Beauchamp et al., 2008, pp. 15-19) – traits often thought of as exclusive to humans – may be considered. This view is perpetuated by Carl Cohen in his article ‘The Case for the Use of Animals in Biomedical Research’ (Cohen, 1986, p.104, cited in Baird & Rosenbaum, 1991, p.116). Cohen claims that “Rights arise, and can be intelligibly defended, only among beings who actually do, or can, make moral claims against one another”.

Numerous studies, however, have established some degree of intelligence and moral agency in pigs (Désiré & Boissy, 2002), lessening the perceived gap between human and non-human animals. Furthermore, humans are – by definition – members of the animal kingdom. It seems that many of the reasons we hold for being ‘special’ in the animal kingdom apply equally to other members, to varying degrees. In response, one might argue that humans hold the upmost degree of rationality and moral agency, among other discussed factors, and that this constitutes superiority. How, though, does a greater degree of rationality authorise acts of domination and exploitation? There are certainly cases upon which humans lack these capacities (in human groups such as the intellectually disabled) to a greater degree than, for example, pigs. Yet it would be considered unjust among most to announce ones superiority over such people. It seems, therefore, that our mental capacities are not morally significant and thus cannot be seen as justification to claim superiority over non-human animals.

In Brute Science, Hugh LaFollette and Niall Shanks (1996, pp. 209-212), we imagine a man, Jones, who relishes in the act of murdering animals. Jones, they say, would be rightfully considered immoral, a view not based on the reactions of other humans to his actions, but because there is an innate sense in which abusive treatment of animals is wrong. Our moral intuitions recognise limits to the degree of abuse that animals should endure and acknowledge moral status in non-human animals. In Introduction to the Principles of Morals and Legislation (1907), Jeremy Bentham argues that these limits can be quantified upon recognising capacities to endure pain and suffering. He writes “The question is not, Can they reason? nor, Can they talk? but, Can they suffer?”, representing his Utilitarianist standpoint. Furthermore, Immanuel Kant argues that from a Kantian perspective, “We can judge the heart of a man by his treatment of animals” (Kant, 1997, p. 212). According to both of these ends of the moral spectrum, there are limits to the degree of harm we inflict upon animals. Therefore, it is clear that animals have intrinsic moral value in of themselves. As pigs have moral value, their use should be avoided through exploring possible alternatives.

Chapter 80 of the Animal Welfare Act (1999), section (2) (b) (iii) requires researchers “to replace animals as subjects for research, and testing by substituting, where appropriate, non-sentient or non-living alternatives”. Based on this imperative and with regard to our case, were pigs really necessary?

Certified forensic equipment supplier Lynn Peavey (2006), based in the US, stocks and sells research equipment to law enforcement agencies and laboratories. Included in their catalogue are mannequin heads built for the very purpose of blood spatter analysis resulting from gunshot wounds. These products sell at $365.00 per head and are each refillable using synthetic blood meaning that only one is required for an experiment like that in our case study. When compared with the estimated price of adult pigs in New Zealand ($100-$2501), multiplied by five – the number of live pigs that were purchased for use in the study – it seems both monetarily and ethically sensible to choose the synthetic model.

Thus far, I have examined aspects of the experiment that undermine its necessity for pig use. The most significant objection against it lies, however, in the accuracy of the data retrieved. Pigs differ to humans in anatomical aspects that would impact the data of our case. Skull thickness in pigs comparative to humans, for instance, is a concern relevant not only in our case study, but in biomedical research in general. Michael Swindle et al (2012) comment on this issue, stating that “The main issue with neurosurgery in the pig is the thickness of the skull and the massive bone structure of the vertebrae”. The density of bone in pig skulls means that they are not analogous to human skulls. Human bone is abnormally thin compared to other species. One cannot be substituted for another.

In the context of our case study, skull thickness – or more specifically frontal sinus volume – would greatly impact the accuracy of data. In the shooting of pigs and humans, penetrating the brain through the skull requires differing levels of force. Based on the loss of energy that each bullet encounters upon breaching the skull, bullet trajectory and velocity will vary, which in turn causes unique blood spatter patterns. For these reasons it is reasonable to believe that blood spatter patterns from humans shot in the same way would be vastly dissimilar to those from pigs.

Not only are we morally obliged to condemn unnecessary suffering, but we have a legal obligation to do so. Chapter 100 of the Animal Welfare Act (1999) requires animal ethics committees to assess any presented application under a set of criteria. Section (e) of this set of criteria asks “whether the design of the experiment or demonstration is such that it is reasonable to expect that the objectives of the experiment or demonstration will be met”. Our case, “Simulating backspatter of blood from cranial gunshot wounds using pig models” fails to fulfil this criterion. Therefore, with the knowledge that pig skull density yields inaccurate data, we can conclude that the approval of this experiment was a violation of the Animal Welfare Act (ch.100), and was inadequately examined by the Animal Ethics Committee of the University of Otago.

Upon examining this case, it seems as if this animal ethics committee made an unjustified decision – based on the experiment’s immoral and unscientific nature – in approving our case study’s experiment. This experiment violates certain sections of the Animal Welfare Act, with which all ethics committees in New Zealand are required to comply. It is clear that certain sections of chapter 100 were not adequately considered. Therefore, a system must be initiated to oversee all animal ethics committees that are involved in authorising research involving animals.

An alteration to the Animal Welfare Act would increase the effectiveness of future committees’ considerations that are made under similar circumstances. My proposed alteration would be the requirement for a formal report of each investigation, including evidence of consideration to chapter 100 of the Animal Welfare Act. It is reasonable to say that, with such a system in place, incorrectly authorised research would be minimised, negating pain and suffering that may have otherwise arisen.

In conclusion, blood spatter research involving the use of live pigs cannot be justified as a ‘necessary evil’. As I have shown, animals have an inherent moral status which justifies their worth as ends to themselves; not simply as expendable ‘tools’ in research. Animal ethics committees across New Zealand are required to follow certain procedures upon approving research involving the use of animals. These methods are contained within the Animal Welfare Act (Part 6), and, after close inspection, two violations were noticed. The first asks if it is reasonable to find other means of accomplishing research that does involve the use of animals. This was relevant to our case study, as there are other methods of data collection that could have been used. Furthermore, the use of pigs in this particular experiment yielded inaccurate results, leading to the second violation since the use of animals must produce relevant data to the aim of the experiment. Again, this was disputed, in light of the physical differences in both pig and human skull size that would alter data. To conclude, I made a recommendation that may help negate future occurrences of similar matters.

In this case, the Animal Ethics Committee of the University of Otago did not recognise the moral value of pigs’ lives. As a result of this, they did not consider possible alternatives to pigs in data collection. Furthermore, they failed to recognise the anatomical differences between both humans and pigs. Therefore, the deaths of pigs were not ‘necessary evils’, but rather – evils that were not at all necessary, yet perpetrated by lack of moral consideration. The New Zealand government needs to recognise that these deaths were preventable and modify the existing act accordingly, for the sake of future animals in similar cases.


Augenstein, S., (2015), ‘Studying Gunshot Backspatter by Shooting Live Pigs?’, Forensic Magazine. Retrieved 22/29/2015, from:

Baird, R. & Rosenbaum, S., (1991), Animal Experimentation: The Moral Issues, 1st ed., Prometheus Books: New York.

Beauchamp, T., et al., (2008), The Human use of Animals, 2nd edn., New York: Oxford University Press.

Bentham, J., (1907), Introduction to the Principles of Morals and Legislation, 2nd ed., Clarendon Press: Oxford.

Désiré, L. & Boissy, A., (2002), ‘Emotions in farm animals: a new approach to animal welfare in applied ethology’, Behavioural Processes, vol. 60, no. 2, pp.165-180.

Kant, I., (1997), Lectures on Ethics, Cambridge University Press: Cambridge.

LaFollette, H. & Shanks, Niall., (1996), Brute Science: Dilemmas of animal experimentation, 1st edn., Routledge: London.

‘Lynn Peavey’., (2006), Blood Spatter Heads. Retrieved 21/09/15, from:

Parliamentary Counsel office., (1999), Animal Welfare Act 1999. Retrieved 17/09/15 from:

Swindle, M., et al., (2012), ‘Swine as Models in Biomedical Research and Toxicology Testing’, Veterinary Pathology, vol. 49, no. 2, pp. 344-356.

Talbolt, M., (2012), Bioethics: An Introduction, 1st edn., Cambridge University Press, United Kingdom.

  1. Estimates referring to cost of pigs were calculated based on average prices of adult pigs on, with emphasis on the pig breeds that resembled those in photos of the study. ↩︎
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