Is your dog smart enough? A new study reveals a surprising secret about their brain size
Do you know some of the best detectives in the world—who have been involved in solving bizarre cases—have four legs, a wagging tail, and an uncanny sense of smell? Yes, we are talking about dogs. Considered as one of the most intelligent animals, they play a crucial role in police forces worldwide. With their sharp instincts, social intelligence, and ability to sense danger, they help track criminals, detect explosives, and even rescue people from distress. But what if we told you that not all dogs are equally intelligent? Well, a study published in Biology Letters has challenged common beliefs and revealed a surprising fact about canines. According to the study, their intelligence is inversely proportional to brain size. You read that right! The smaller the brain, the sharper the dog!
For this extensive study, researchers examined the skulls of over 1,500 fully grown dogs from 172 breeds using specimens from Switzerland's Natural History Museum Bern. To analyze cognitive ability, the researchers measured the dogs' relative endocranial volume (REV)—in layman's terms, it's the brain size relative to body size. "Throughout time, most animals have increased their relative brain size. The hypothesis is that a bigger brain helps us to survive; it helps us to out-compete other animals. In the dog, it’s exactly the opposite—in this one way that we are measuring cognitive ability," Dr. Ana Balcarcel, an evolutionary biologist at the Montpellier Institute of Evolutionary Sciences, quoted by BBC.
Depending upon favorable traits, the study also revealed how dog breeds were selectively bred, which shaped their intelligence and behavior in different ways. While toy breeds like the Chihuahuas, Pugs, and Yorkshire Terriers, among others, have larger relative brain sizes, working breeds like Siberian huskies have smaller relative brain sizes. Going by the findings of the study, toy breeds often bred for companionship have higher levels of fear, aggression, separation anxiety, and attention-seeking behavior. On the other hand, working breeds trained to be more "trainable" are more socially intelligent. "We can say that we have really altered the brains—not just the body sizes and the proportions of different dogs, but it looks like we have also changed their brains in a significant way," Balcarcel added.
The researchers hope to identify which senses and skills matter most for each type of dog by comparing the neocortex's shape in different breeds. This could probably explain how brain structure affects behavior, trainability, and specialized abilities, Balcarcel shared. Not just that, analyzing brain form can also shed light on the evolution and domestication of canines. Although domesticated dogs have about 20% smaller brains than those of wild gray wolves relative to body size, dogs have developed specialized skills that help them to cooperate with humans. This reveals that factors like domestication help in shaping the dogs' cognition, prioritizing social intelligence over brain size.
However, as per a report in Live Science, Balcarcel urged dog owners to not blindly follow the study's findings. She shared that their dog's brain size relative to their body doesn't necessarily translate into their dog's intelligence. "Dogs have been bred for different cognitive abilities. So even if your dog is on the small-brained end of things, they are special and specialized in their own way," she added.