Why measuring donkeys’ IQ might save them from extinction
Summary: Researchers in Spain and the U.S. have come up with a test that measures donkey IQ, which may help to breed donkeys with the traits that humans consider most useful.
Measuring the IQ of animals has been a topic of interest to researchers since at least 1883, when Nature wrote about the intelligence of cats and chickens. In recent years, studies have been conducted into the IQs of chimpanzees, dolphins, elephants, dogs, pigs, horses, raccoons, rodents, parrots, pigeons, lizards, snakes, turtles, fish, and spiders, to name just a few.
The latest animal to join this club is the Equus asinus: researchers in Spain and the United States have now come up with a test that measures donkey IQ.
Regaining lost status
As the researchers explain in their recent paper, donkeys were once considered elite animals, for example in the Egypt of 5,000 years ago. But their reputation has declined considerably since then. In the Bible, as well as in the works of Homer and Aesop, donkeys are portrayed as stupid, stubborn, servile, and low-status, especially in contrast to horses, which were seen as exalted and beautiful. This low status is reflected in many languages that have derogatory words for donkey, such as “asinine.” Even the title of this current paper (“Dumb or smart asses?”) playfully refers to this lowly history.
And that matters, because the way we represent animals also influences our treatment of them. Donkeys have been dutifully carrying our stuff for millennia, but get little respect in return. Although there are currently about 40 million donkeys in the world, their importance as pack animals is in decline, as they are increasingly replaced by vehicles and machines. In fact, the Andalusian donkey, which was the type studied in this research project, is currently categorized by the Spanish government as an endangered breed.
Popular as therapy animals
It’s tragic for any animal to face extinction, but it’s especially unfortunate in this case because donkeys have been growing increasingly popular as “therapy animals,” especially for autistic children. This is largely due to what the researchers refer to as their “empathic nature,” and this nature very much has to do with how donkeys have evolved to interact with humans.
And that’s where the IQ test comes in: learning more about donkey’s cognitive skills means that people can breed donkeys with the traits that make them maximally desirable as therapy animals.
A g factor for donkeys
In consultation with donkey breeders, the researchers came up with a list of 13 traits that express donkeys’ cognitive skills, such as memory, trainability, concentration, and curiosity.
The team then devised a task that allowed them to rate about 300 donkeys on each of these 13 traits, on a scale of 1 to 5. The task involved placing a cloth in front of the donkey and observing how it reacted, both with and without prompts.
The researchers found significant positive correlations between almost all of the cognitive traits they measured, ranging from 0.12 (the correlation between alertness and dependence) to 0.81 (between memory and trainability).
And these correlations mean that something akin to a or general intelligence, also applies to donkeys. The “low IQ” donkeys, for example, tended to share a cluster of traits that included being difficult to train, uncooperative, and less able to memorize an assigned task.
As the researchers put it, “Our results provide some of the first evidence that an analogous factor to human g may underpin cognitive performance in donkeys and account for a similar distribution in the human population.”
Their results also suggest that donkey IQ follows the same Gaussian distribution found in human IQ. Genetically, the heritabilities of these 13 traits ranged from 0.06 (for dependence) to 0.38 (for the ability of the donkeys to enter or leave their stables).
Breeding for desirable traits
This knowledge lets breeders select for donkeys that are more easily trainable, more willing to cooperate, easier to handle, and more likely to remember new tasks. The researchers add that as they amass more data, even more reliable cognitive components, with higher heritabilities, will likely be discovered.
This research may also open a new path toward finding specific genes that lead to these desirable behavioral traits in other therapy animals, or even to a better understanding of the underlying biological mechanisms behind cognitive processes in humans.
In sum, the researchers write: “There are donkeys which are more intelligent than others, and the present methodology enables quantifying such differences.”
Study: “Dumb or smart asses? Donkey’s (Equus asinus) cognitive capabilities share the heritability and variation patterns of human’s (Homo sapiens) cognitive capabilities” ( link)
Authors: Francisco Javier Navas Gonzáleza, Jordi Jordana Vidal, José Manuel León Jurado. Amy Katherine McLean, Juan Vicente Delgado Bermejo
Published in: Journal of Veterinary Behavior, Volume 33, September-October 2019, Pages 63–74