Why it's so offensive when we call people animals

Comparing humans to animals is vexed but irresistible. We are animals, but animals who like to believe we are not merely animals. When we do liken people to other creatures – when sports fans use racial slurs or Donald Trump calls Syrian President Bashar al-Assad an “animal” – fur often flies.

People draw animal comparisons using countless expressions, many of which convey positive sentiments. Cute, diminutive animals provide pet names for children or lovers. Valued animals symbolise desirable human traits: brave people are lion-hearted and perceptive ones eagle-eyed. People identify with the totemic animals of their football clubs.

Other animal metaphors are more neutral, offering a sort of zoological shorthand for the full range of human attributes. Calling someone a sheep implies they are conformist, whereas calling them a chicken or mouse suggests fearfulness and timidity. Calling someone a cow or toad speaks to their physical rather than psychological characteristics.

This shorthand varies across cultures and languages. In the West owls are wise, but in India they represent foolishness. Calling someone a shark in the English speaking world implies they are dishonest and rapacious, but in Persian it refers to a man with little or no beard.

Many animal metaphors are straightforwardly offensive rather than simply representing a particular trait. Calling someone a pig, rat, ape, monkey, dog, maggot or leech carries a derogatory meaning and a strong emotional and moral charge. But what is it about these animal comparisons that makes them offensive?

Offensive metaphors

In one study, my colleagues and I explored the meanings conveyed by an assortment of animal metaphors and examined what features made some of them especially offensive. We found that two features were particularly potent.

First, and perhaps not surprisingly, intensely reviled animals such as snakes, leeches and rats make more insulting metaphors. When people use these metaphors to refer to a person they do not imply that the person is literally like these animals. Rather they transfer the disgust felt towards the animal to the person.

Second, we found that some animal metaphors are highly objectionable because the comparison itself is dehumanising. When people call others apes, monkeys or dogs, for instance, they are likening them to animals that are not disliked, unlike rats or snakes. However these metaphors convey the message that these people are literally subhuman.

In short, some offensive animal metaphors are degrading whereas others are disgusting.

It is no accident that these two distinct kinds of metaphor feature in some of history’s most appalling conflicts. Dehumanising ape metaphors were commonly applied to Indigenous people during colonial wars and conquests. Disgust-based metaphors picturing people as vermin and cockroaches dominated the imagery of the Holocaust and the Rwandan genocide.

The idea of animality

Although only some animal metaphors are highly offensive, most appear to be somewhat negative in their connotations. One study found a clear majority to be judged uncomplimentary – especially those most often addressed to men – and another showed animal metaphors primarily represent negative attributes.

Our research suggests the most common of these negative attributes are depravity, disagreeableness and stupidity. In essence, when we call someone an “animal” in the general sense, we are ascribing these flaws to them. Humans are moral, civil and smart; animals are not.

Indeed, it has been argued animal metaphors reveal a deep sense of hierarchy in nature. According to the ancient idea of the scala naturae or “great chain or being”, humans sit one step above animals, who themselves sit above plants and then minerals. Just as we are on the third rock from the sun, we are on the third step from the top of the ladder, with God and angels above us.

In this hierarchy humans have supposedly unique powers of reason and self control, whereas animals represent unrestrained instinct. To call someone an animal is therefore to demote them to a lower rung of existence, a more primitive state of being where they lack human virtues.

It would be comforting if dehumanising metaphors and hierarchical ideas about humans and animals were just historical curiosities. Regrettably there is ample evidence that they endure. People are surprisingly willing to rank some humans as less human, and more primitive, than others. Animal metaphors shine a revealing light on that beastly reality.