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Dog Breeding Has Changed Pooches’ Brains | Smart News

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Humans and dogs share a long, intertwined history; we’ve been breeding our best floofy buds for thousands of years. All this tinkering with dog DNA has led to a plethora of diverse pooches, from the Great Dane to the tiny Chihuahua. And according to a new study published in J Neurosciby breeding selectively for certain traits, humans also played a role in shaping the brains of dogs.

Different breeds are well known for exhibiting varying behavioral characteristics. Border collies are avid breeders, for example, while dachshunds dig up just about anything they can get their paws into; they were, after all, bred to hunt tunnel-digging animals. “These behavioral differences must be the result of underlying neural differences,” the study authors write, “but surprisingly, this topic has remained largely unexplored.”

Hoping to shed new light on neural functions in dogs, the research team looked at MRI scans from 62 dogs from 33 different breeds. The puppies had been scanned at the University of Georgia Veterinary Teaching Hospital and found free of any neurological abnormalities. The researchers used data from the American Kennel Club to group the dogs into different categories based on their “behavioral specialization” or what appears to have been the original intent of their breed – for example, scent hunting ( basset hounds and beagles), herding (Welsh corgis and Old English Sheepdogs) and “explicit companionship” (Maltese and Yorkie terriers).

The first order of business was to determine if brains varied in shape and size across races, which, perhaps unsurprisingly, they did. As Liz Langley points out in National geographic“[D]ogs bred to be small – say the lhasa apso – have round heads with equally round brains that take up most of their skulls. A larger breed like a golden retriever has a long, narrow head, and therefore a more elongated brain that doesn’t fill the entire skull space.

But such differences in brain anatomy “go beyond differences in body size, brain size, and just the general shape of the head,” Erin Hecht, assistant professor of evolutionary biology at Harvard and lead author of the new study, tells Ed Cara of Gizmodo. The researchers looked at the areas of the brain with the greatest anatomical variations between different races and used this information to generate maps of six distinct brain networks. The first network, for example, encompassed parts of the brain associated with reinforcement learning. Network four, on the other hand, comprised “higher-order cortical regions likely to be involved in social action and interaction.”

The team found that anatomical variations in dogs’ brain networks were associated with variations in their behavior. So breeds like golden retrievers, which were bred to visually follow birds, displayed key distinctions in parts of the brain related to “coordination, eye movements, and spatial navigation,” as Cara explains. The second network, which involved parts of the brain associated with smell and taste, “showed a significant correlation with scent hunting,” according to the study authors.

“The anatomy of the brain varies between dog breeds,” Hecht explains in an interview with Jason Bittel of the Washington Post“and it appears that at least some of this variation is due to selective breeding for particular behaviors like hunting, herding, and guarding.”

It’s important to note, as the study authors do, that the new paper only represents some of the 202 dog breeds recognized by the American Kennel Club, and it’s possible that a different composition of the sample produced different patterns of brain variation. It’s also important to note that all of the dogs involved in the new paper were pets and therefore do not fulfill the role for which they were originally bred. “[F]Future studies of purpose-bred dogs that actively perform the tasks for which they are presumably adapted might expect to find additional or more pronounced neuroanatomical effects than those we observed here,” the study authors write. .

In the future, Hecht and her team hope to better understand why dogs of the same breed display diverse behaviors: “For example, border collies winning real-world herding contests,” she tells Bittel, “and the siblings of those dogs who for some reason just prefer to sit on the couch.

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