The basis of animal rights is the recognition that animals are sentient beings.

This means they are capable of being aware of sensations and emotions, of feeling pain and suffering, and of experiencing a state of well being. ARAs believe that our own behaviour towards animals should be guided by this recognition of their sentience.

Most of us use animal products every day, but how much do we know about the animals' needs and wants, or about their emotional lives?

What is Animal Sentience – and why does it matter?
Humans share the planet with as many as 4700 species of mammals, 9700 species of birds, 4800 species of amphibians, over 23,000 species of fish and around 6000 species of reptiles (as far as we know up to now), not to mention the countless species of invertebrate animals. We interact with and use animals in a multitude of ways in our daily lives.

But how much do we know about how these animals experience the world – what they feel, why they behave in the ways they do, how they understand their environment, how and what they communicate?

Many of us at some time must have watched another animal – a dog, a cat, a horse, a bird, a flock of sheep – and wondered, ‘What is she feeling now?’ or ‘Why is he behaving like that?’ or ‘What do they want?’. Questions like these may seem simple, even simple-minded, but in fact they are very complex and important to our understanding of the place of humans in the natural world.

Increase in scientific knowledge
A huge increase in scientific research on animal sentience is beginning to answer some of the questions about animal sentience and animal consciousness, although many unsolved mysteries and questions remain for future study and debate. This will be one of the most exciting areas of biology in the coming decades. And the answers have big implications which are being explored by philosophers and lawyers. How should we treat other animals? What are our responsibilities to them? Do they have rights?

Scientific studies of Animal Sentience
The most basic way of experiencing the world is through feeling or sensation. ‘Sentience’ is defined as the ability to have perceptions and sensations. A ‘sentient animal’ is an animal that is aware of his/her surroundings and of what happens to him/her and is capable of feeling pain and pleasure, at the least. The current scientific consensus is that all vertebrate animals, at least, are capable of feeling pain and experiencing distress. (For this reason anti-cruelty laws exist in many countries.)

But many of the animals we interact with turn out to have more complex mental and emotional lives than people have understood in the past, and new scientific research is constantly revealing new evidence of animals’ cognitive abilities and their emotions.

Sentient animals have preferences and intentions
It turns out that some animals can both remember and anticipate events and some can foresee their future needs and plan ahead. They can maintain complex social relationships in their groups. Some animals can understand what another animal is going to do, and attempt to deceive that animal in order to gain an advantage. Some animals can enjoy learning a new skill. Some animals react to other animals in ways resembling human empathy. On the negative side, animals can experience the unpleasant emotions of pain, fear, frustration and probably boredom as well. They can be reduced to a state resembling human depression by chronic stress or confinement in a cage.

All these abilities listed above have been documented in scientific research. Of course these abilities vary between different species. And of course we cannot assume that if an animal behaves in ways that look familiar to us, the animal has the same mental experiences as a human would have in similar circumstances. In the current state of knowledge it is impossible to prove beyond doubt what an animal is feeling, or perhaps thinking. But it is equally important not to underestimate animals’ feelings and the sophistication of their mental processes, because this may well affect how we behave towards animals.

Importantly, several of the abilities that have in past been thought to be uniquely human – for example, the use of tools, the ability to plan ahead, the ability to empathise with another or to deceive another, the transmission of skills in ways that can be classified as ‘culture’, behaviour that can be classified as ‘morality’ – are now known to exist to some extent among non-human animals too. From the point of view of evolutionary biology, it makes sense that humans should share many of our emotional and cognitive abilities with some of the other animal species.

Understanding animals
Throughout history people have known that animals do very ‘clever’ and impressive things – such as a bird building an intricate nest or a mother animal teaching her young. Folk stories all over the word attribute intelligence and cunning to animals.

But for much of the 20th century scientists believed that all animal behaviour could be explained either as innate behaviour patterns in response to internal or external stimuli or as conditioned learning in response to stimuli.

Emotion or problem-solving on the part of the animal were not considered necessary to explain its behaviour and it was considered impossible to study these aspects at all. What is exciting about the present time is that scientists are once again interested in studying animals’ emotions and mental processes and that huge progress in understanding animals is being made.

Implications of Animal Sentience
The facts and theories of animal sentience are still hotly debated among scientists and philosophers. But most people have over history assumed that many animals feel pain, hunger, thirst, heat, cold, fear, anger and other basic emotions, because we have everyday evidence that they do.

Why use a whip or stick on a horse unless it feels unpleasant enough to make the horse move faster? If a dog, horse or cow is limping, most people would naturally assume that the animal is in pain. Most people would also assume that the pain is distressing to the animal and, if they could, they would try to do something to alleviate it.

However, throughout history humans have also treated animals in ways that caused great suffering to the animals, whether intentionally or unintentionally.

Today there is increasing concern about the welfare of animals, whether these are wild animals or those used by people for food, work, companionship, entertainment, sport or scientific research.

From Darwin to Dawkins: The science and implications of Animal Sentience
In March 2005, CIWF hosted an international conference on animal sentience in London. Dr Jane Goodall DBE gave the keynote address suggesting that the burden of proof should not be on those trying to prove the sentience of animals, but rather on those seeking to disprove it. A free DVD showing highlights from Compassion in World Farming's major international conference is now available to order online.

In the future, Compassion in World Farming plans to develop a set of animal sentience web pages that will aim to provide:

Updates on current scientific research on animal sentience, based on findings in disciplines ranging from animal behaviour to neurobiology

Reviews of particular areas of animal sentience research

Stories relevant to animal sentience in the media

Updates on how animal welfare science is progressing animal welfare at a practical level across the world

Guest articles on science, ethics and law relating to animal sentience

A special section for younger students

Further reading - selected suggestions

Applied Animal Behaviour Science 100:1-2, Oct 2006. Special issue: sentience in animals. - Selection of scientific papers from Compassion in World Farming's conference, From Darwin to Dawkins: The science and implications of animal sentience, March 2005.

J D'Silva and J Turner (eds), 2006. Animals, ethics and trade. Earthscan. Further papers from Compassion in World Farming's conference, From Darwin to Dawkins: The science and implications of animal sentience, March 2005. Foremost international experts examine the philosophical, legal, policy and practical implications of our current knowledge of animal sentience.

M Bekoff (ed), Jun 2007. Encyclopedia of human-animal relationships. Greenwood Press

F D McMillan, 2005 (ed). Mental health and well-being in animals. Blackwell Publishing

J Webster, 2005. Animal welfare: limping towards Eden. Blackwell Publishing

T Grandin and C Johnson, 2005. Animals in Translation: Using the Mysteries of Autism to Decode Animal Behavior. Scribner

M Bekoff (ed), 2004. Encyclopedia of Animal Behavior. Greenwood Press

N G Gregory, 2004. Physiology and behaviour of animal suffering. Blackwell Science

F B M de Waal and P L Tyack, 2003. Animal social complexity: intelligence, culture, and individualized societies. Harvard University Press

S M Wise, 2002/3. Drawing the line: science and the case for animal rights. Perseus Publishing

D R Griffin, 2001. Animal minds: beyond cognition to consciousness. University of Chicago Press

L J Keeling and H W Gonyou (eds), 2001. Social behaviour in farm animals. CABI Publishing

M Hauser, 2000. Wild minds: what animals really think. Henry Holt and Company

C Moss, 2000. Elephant memories: thirteen years in the life of an elephant family. University of Chicago Press.

M S Dawkins, 1998. Through our eyes only? The search for animal consciousness. Oxford University Press

A Manning and M S Dawkins, 1998. An introduction to animal behaviour. Cambridge University Press

F Fraser and D M Broom, 1997. Farm animal behaviour and welfare. CABI Publishing