Are dogs more intelligent than cats? An online article stated dogs had bigger brains and were therefore more intelligent than cats.

In the past 20,000 years of our shared history, dogs have gone from being our hunting partners and livestock herders to participating in search and rescue teams and law enforcement, acting as lifeguards, and assisting people with disabilities. Cats, however, have remained mere rodent catchers for 5,000 years.

Having known both cats and dogs, I was tempted to agree with the article’s conclusion. But I wasn’t convinced by the ‘big brain, more intelligence’ theory, since I’d have to concede that Rom was smarter than me.

In 1836, German anatomist Friedrich Tiedemann was the first to suggest that humans with bigger brains were more intelligent than others. Nineteenth-Century anthropologists obsessively measured human brains of every race they could. After World War II, the whole theory smacked of racial prejudice.

Neanderthals had larger brains than modern humans. Men have larger brains than women. One would expect Einstein’s brain to be larger than average human brains, but it is smaller. Yet, some scientists argue there is a general trend towards higher intelligence with increase in brain size. While argument rages over using brain size as an indicator of intelligence in humans, biologists apply the big brain rule to animals.

Dogs generally are larger than cats, and among mammals, big brains are needed to control large bodies. Elephants and blue whales have the largest brains. To what degree does a large brain reflect intelligence?

There was another assumption: social animals like dogs are smarter than solitary animals such as cats. According to the Social Brain Hypothesis proposed by evolutionary biologist Robin Dunbar in 1998, primates have large brains because of their hectic social lives. When social primates forage together, they compete with one another, but also cooperate so the group procures more food. Selfish desires and altruistic interests call for problem-solving skills that require extra brain power.

The Social Brain Hypothesis works differently in other mammals. Monogamous species have larger brains than polygamous ones. The lives of canid packs revolve around a breeding pair. Lions form coalitions with other males, and live with prides of lionesses. Except lions, felines don’t have an intense social life.

I wondered if lions were smarter than tigers. Although solitary tigers and social lions have roughly similar body size, tigers’ brains are larger by 16 per cent. Even tigresses from Bali, the smallest of the species, have a similar brain size to large South African lions. Lions’ brains ought to be the largest, according to the hypothesis. However, Nobuyuki Yamaguchi of the University of Oxford, one of scientists who examined feline skulls, says there is no connection between brain size and social life among cats.

How do we measure intelligence of two animals with different brain sizes and social lives, especially if you can’t give them an IQ test? Biologists commonly use the Encephalization Quotient (EQ) that takes body and brain sizes into account. The value is derived after deducting the estimated brain size needed to control the species’ body mass from the actual brain size of the animal. For instance, on average, our brains are seven times larger than expected for our body size.

Humans come in many shapes, sizes, and weights — from short, stocky Nepalis to tall, lean Maasai. Body fat skews EQ, making trim people appear smarter than the obese. Therefore EQ is considered inappropriate for humans.

Even among other mammals, EQ doesn’t work across the spectrum. Small capuchin monkeys from South America have a greater EQ value than the more intelligent great apes. Until intelligence tests become fool proof, EQ continues to be used to measure animal intelligence. Dogs’ EQ score is better than cats, and tigers are smarter than lions. Perhaps house cats are smarter than they reveal, receiving the same rewards – our hearts and hearths – as high EQ, hard-working, social dogs without having to do much.