What is sentience?
Sentience is the ability to perceive and feel things.1 It's commonly described as the capacity to feel pleasure and pain.
An animal is sentient if “it is capable of being aware of its surroundings, its relationships with other animals and humans, and of sensations in its own body, including pain, hunger, heat or cold.”2
In 2012, an international group of eminent neuroscientists signed The Cambridge Declaration on Consciousness, which confirmed that many animals, including all mammals and birds, possess the “neurological substrates that generate consciousness.”3
Is sentience important?
Voiceless believes that humans have an ethical obligation to protect the interests of animals. Cruelty towards animals cannot be justified by their level of cognition, communication skills or species membership, as these traits are irrelevant to an animal’s capacity for suffering and preference for a good life.6
If we accept animal sentience, then certain practices like factory farming must be reconsidered.
How do we know that animals feel pain?
While pain itself cannot be directly observed in another being,7 there is mounting scientific evidence to support the common assumption that animals suffer.
Dr. Bernard E. Rollin, Distinguished University Professor at Colorado State University, explains that:
- “The neural mechanisms responsible for pain behaviour are remarkably similar in all vertebrates.”8
- Pain relieving drugs control what appears to be pain in all vertebrates and some invertebrates. The natural pain-inhibiting systems found in the human body (such as endorphins) are very similar to those found in all other vertebrates.9
- Humans’ capacity to feel pain is a method of survival that is likely to have been preserved during our evolution. “Given that the mechanisms of pain in vertebrates are the same, it strains credibility to suggest that the experience of pain suddenly emerges at the level of humans.”10
DeCamp Professor of Bioethics at Princeton University, Peter Singer, argues that “it is surely unreasonable to suppose that nervous systems that are virtually identical physiologically, have a common origin and a common evolutionary function, and result in similar forms of behaviour in similar circumstances should actually operate in an entirely different manner on the level of subjective feelings.”11
While animals cannot verbally report their feelings as humans do, all other methods of studying human emotions can also be applied to animals.12 These measures have shown that many animals have “rich and deeply emotional lives”.13
While much attention is given to negative feelings such as stress and fear, animal welfare is also dependent on pleasurable emotions.14
Play behaviour is widespread in mammals and many birds. Young calves often have playful fights and prance about,15 while young chickens jump around and flap their wings for fun.16 Animals also find pleasure in the search for and consumption of food, tactile interactions like grooming, sexual activity and basic comforts like basking in the sun.17
Today, millions of animals are denied the freedom to experience these basic pleasures because they are confined in cages, kept in isolation or crowded in sheds without access to a natural environment.
Sentient animals have complex social lives involving communication, organised groups and family bonds.
- Cows are extremely social animals who live in small herds, forming social hierarchies and friendship pairs.18
- Chickens share information with specific calls to communicate their frustration, the discovery of food or the presence of a predator, suggesting some level of language.19
- Familiar pigs greet each other by touching noses and grunting, while those with close bonds may groom each other.20
The disruption of these relationships can severely damage animal welfare.
- Separating bonded individuals like a mother and infant can cause the animals to protest and despair.21 Young piglets separated from their mothers give distinctive and frequent squeals to call her.22 Dairy cows develop a strong maternal bond with their calf after as little as five minutes of contact after birth23 and become stressed when their four-day old calf is removed.24
- Mixing unfamiliar cows can cause a tenfold increase in conflict between the animals.25
- Chickens in large flocks (up to 60,000 can be housed in a single shed)26 can constantly try to establish a social hierarchy without ever achieving it, while overcrowding can cause feather pecking and cannibalism amongst the birds.27
Is there a consensus?
Despite the growing body of scientific evidence, some people remain sceptical of animal sentience.28
This uncertainty should not justify the reckless treatment of animals. “It is morally incumbent upon us to give the animal the benefit of the doubt and to protect it so far as is possible from conditions that may be reasonably supposed to cause it suffering, though this cannot be proved.”29
If all available evidence suggests that animals are sentient, they ought to be treated as such.
The law doesn't recognise animals as sentient
Australian law classifies animals as property and fails to recognise their sentience.
Most animals in Australia are expressly excluded from animal welfare legislation which is “largely limited to isolated acts of cruelty committed against domestic pets, as opposed to large-scale systemic cruelty in institutions of food, science and sport.”30
Animals farmed for food, as well as those used for other human purposes, are instead governed by Codes of Practice31 which allow for many cruelties, including the castration of piglets without pain relief and the confinement of their mothers in individual cages32 - acts which are illegal when inflicted on companion animals like dogs and cats.
“Farm animals feel pleasure and sadness, excitement and resentment, depression, fear and pain,” explains Dame Jane Goodall PhD, Patron of Voiceless.33
“They are far more aware and intelligent than we ever imagined and, despite having been bred as domestic slaves, they are individual beings in their own right. As such, they deserve our respect.”
Read Ondine Sherman's opinion piece on sentience, 'A dog is a cow is a pig' here.
Last updated October 2018
- 1. Judy Pearsall, Sentient (Oxford Dictionaries) http://oxforddictionaries.com/definition/english/sentient.
- 2. Jacky Turner, Stop – Look – Listen: Recognising the Sentience of Farm Animals (Compassion in World Farming Trust, updated version, 2006) 6.
- 3. Philip Low, ‘The Cambridge Declaration on Consciousness’ (Paper presented at the Francis Crick Memorial Conference on Consciousness in Human and Non-Human Animals, Churchill College, July 7 2012) 2 http://fcmconference.org/img/CambridgeDeclarationOnConsciousness.pdf.
- 4. Gary Francione, Sentience (2012) Animal Rights: The abolitionist approach http://www.abolitionistapproach.com/sentience.
- 5. John Webster, Animal Welfare: Limping Towards Eden (Universities Federation for Animal Welfare, 2005) 11.
- 6. The philosopher Jeremy Bentham famously said that in matters of animal ethics, “The question is not ‘Can they reason? nor Can they Talk but, Can they suffer?”. This opinion is supported by John Webster, Emeritus Professor of Animal Husbandry at Bristol University School of Veterinary Science. See Webster, Ibid, 11; It is “a common misconception that the capacity for sentience is linked in some way to a species’ cognitive ability.” See Helen Proctor, ‘Animal Sentience: Where Are We and Where Are We Heading?’ (2012) 2 Animals 628, 631; Peter Singer explains why discrimination on the basis of species alone is unethical. See Peter Singer, Animal Liberation (Harper Perennial edition, 2009) 6.
- 7. Jonathan Balcombe, ‘Animal pleasure and its moral significance’ (2009) 118 Applied Animal Behaviour Science 208, 209
- 8. Bernard E. Rollin, ‘Animal Pain’ in Susan J. Armstrong and Richard G. Botzler (eds), The animal ethics reader (Routledge, 2003) 86.
- 9. Ibid.
- 10. Ibid 87.
- 11. Singer, above n 6, 11.
- 12. Animals’ emotional states like fear or aggression are evident in their physiological responses such as an increase in heart rate or hormone levels. They can indicate whether they find something positively or negatively reinforcing by pressing a lever or door. Like humans, animals also have specific vocalisations, expressions and behaviours associated with their emotional experiences. See Maria Stamp Dawkins, ‘The Science of Animal Suffering’ (2008) 114 Ethology 937, 940.
- 13. Marc Bekoff, The Emotional Lives of Animals (New World Library, 2007) xviii.
- 14. John Webster, Animal Welfare: Limping Towards Eden (Universities Federation for Animal Welfare, 2005) 41.
- 15. Stephen J G Hall, ‘Behaviour of Cattle’ in Per Jensen (ed), The Ethology of Domestic Animals (CABI Publishing 2002) 131, 140.
- 16. Michael C Appleby, Joy A. Mench and Barry O. Hughes, Poultry Behaviour and Welfare (CABI Publishing 2004) 137.
- 17. Balcombe, above n 7, 211-13.
- 18. A Fraser and D Broom, Farm Animal Behaviour and Welfare (CABI Publishing, 3rd ed, 1996).
- 19. Suzanne T Millman and Ian J.H. Duncan, ‘Social Cognition of Farm Animals’ in L.J. Keeling and H.W. Gonyou (eds), Social Behaviour in Farm Animals (CABI Publishing, 2001) 373, 389-390.
- 20. D G Wood-Gush ‘Introduction to Social Structures Communication’ in Elements of Ethology (Chapman & Hall, 1983), cited in Jacky Turner, Stop – Look – Listen: Recognising the Sentience of Farm Animals (Compassion in World Farming Trust, updated version, 2006) 20.
- 21. Ruth Newberry and Janice Swanson, ‘Breaking Social Bonds’ in L.J. Keeling and H.W. Gonyou (eds), Social Behaviour in Farm Animals (CABI Publishing, 2001) 307, 310.
- 22. D M Weary and D Fraser, ‘Vocal Response of ‘Piglets to Weaning: Effect of Piglet Age’ (1997) 54 Applied Animal Behaviour 53-160.
- 23. Susan J. Hudson and M.M. Mullord, ‘Investigations of maternal bonding in dairy cattle’ (1977) 3 Applied Animal Ethology, 271-276.
- 24. A Sandem and B Braastad, ‘Effects of Cow-Calf Separation on Visible Eye White and Behaviour in Dairy Cows – A Brief Report’ (2005) 95 Applied Animal Behaviour 233.
- 25. Marie-France Bouissou et al, ‘The Social Behaviour of Cattle’ in L.J. Keeling and H.W. Gonyou (eds), Social Behaviour in Farm Animals (CABI Publishing, 2001) 113, 131.
- 26. Dr Vivien Kite, Growing Meat Chickens (7 September 2007) Australian Chicken Grower’s Council http://www.acgc.org.au/resource_material/more/28.
- 27. Joy Mench and Linda J. Keeling, ‘Social Behaviour of Domestic Birds’ in L.J. Keeling and H.W. Gonyou (eds), Social Behaviour in Farm Animals (CABI Publishing, 2001) 177, 194-8.
- 28. Jane Goodall, ‘Foreword’ in Mark Bekoff, The Emotional Lives of Animals (New World Library 2007) xi, xiii.
- 29. Report of the Technical Committee to enquire into the welfare of animals kept under intensive livestock husbandry systems (HMSO 1965) quoted in Malcolm Caulfield, Science and Sense: the case for abolishing sow stalls (Voiceless 2013) 23.
- 30. David Glasgow, ‘The Law of the Jungle: Advocating for Animals in Australia’ (2008) 13:1 Deakin Law Review 196.
- 31. For a list of the National Model Codes of Practice, see http://www.publish.csiro.au/nid/22/sid/11.htm. State codes of practice also exist, see for example http://www.dpi.nsw.gov.au/agriculture/livestock/animal-welfare/codes.
- 32. Model Code of Practice for the Welfare of Animals - Pigs (revised) (2007) (‘the Pig Code’), section 4.1 and Appendix 3.
- 33. Jane Goodall, ‘Foreword’ in Amy Hatkoff, The Inner World of Farm Animals (Stewart, Tabori & Chang 2009) 10, 13.