Breeding has given different dogs distinct brain shapes | Science News for Students

Breeding has given different dogs distinct brain shapes

Brain regions involved in smelling and tasting show some of the biggest differences
Sep 30, 2019 — 6:45 am EST
a side view of three different dog breeds

Brain scans from 33 dog breeds revealed a broad variation in regions involved in scent hunting, guarding and companionship.

debbiehelbing/iStock/Getty Images Plus

For centuries, dog breeders have been shaping the way the world’s canines look and behave. Turns out, that meddling in doggy evolution has sculpted the pups’ brains, too.

A team of researchers scanned the brains of 62 purebred dogs representing 33 breeds. They used MRI, or magnetic resonance imaging, to map the shapes of brain structures. Their results show that dog brains are not all alike. The shapes of various brain regions can differ broadly by the breed. The research may guide future studies on how brain structure relates to behavior.

The new findings appeared September 2 in the Journal of Neuroscience.

Erin Hecht studies brain evolution at Harvard University in Cambridge, Mass. She was part of the team that conducted the new study. The distinct brain shapes were not simply due to the breed’s different head shapes, the team found. Nor were differences due to the size of the dogs’ brains or bodies. Instead, Hecht and her colleagues conclude, humans’ selective breeding of their dogs have shaped the animals’ brains, bit by bit.

The dogs were scanned at the Veterinary Teaching Hospital at the University of Georgia at Athens. This study was not designed to directly link brain shape to behavior. But the results do offer some hints. Some parts of the brain varied more than others. Smell and taste regions, for instance, varied a lot between breeds. Those areas may support specialized behaviors that often serve people, earlier studies have suggested. Such behaviors include hunting by smell, guarding and providing companionship.

The authors assumed the dogs in the study were all pets. Working dogs undergo extensive training for specialized jobs, such as herding sheep, finding bombs or guiding the blind. It’s possible that such highly trained dogs might have even more distinct brains.

brain scans of two different dog breeds
Certain brain regions take on a different shape in a basset hound’s brain (left) than the brain of a border collie (right). 
Marc Kent & Erin Hecht

Power Words

(more about Power Words)

behavior     The way something, often a person or other organism, acts towards others, or conducts itself.

breed     (noun) Animals within the same species that are so genetically similar that they produce reliable and characteristic traits. German shepherds and dachshunds, for instance, are examples of dog breeds. (verb) To produce offspring through reproduction.

canine     Members of the biological family of canids. These are carnivores and omnivores. The family includes dogs, wolves, foxes, jackals and coyotes. 

colleague     Someone who works with another; a co-worker or team member.

evolution     (v. to evolve) A process by which species undergo changes over time, usually through genetic variation and natural selection. These changes usually result in a new type of organism better suited for its environment than the earlier type. The newer type is not necessarily more “advanced,” just better adapted to the particular conditions in which it developed. 

journal     (in science) A publication in which scientists share their research findings with experts (and sometimes even the public). Some journals publish papers from all fields of science, technology, engineering and math, while others are specific to a single subject. The best journals are peer-reviewed: They send all submitted articles to outside experts to be read and critiqued. The goal, here, is to prevent the publication of mistakes, fraud or sloppy work.

link     A connection between two people or things.

magnetic resonance imaging (MRI)     An imaging technique to visualize soft, internal organs, like the brain, muscles, heart and cancerous tumors. MRI uses strong magnetic fields to record the activity of individual atoms.

neuroscience     The field of science that deals with the structure or function of the brain and other parts of the nervous system. Researchers in this field are known as neuroscientists.

taste     One of the basic properties the body uses to sense its environment, especially foods, using receptors (taste buds) on the tongue (and some other organs).

veterinary     Having to do with animal medicine or health care.


Journal: E.H. Hecht et al. Significant neuroanatomical variation among domestic dog breeds. Journal of Neuroscience. Published online September 2, 2019. doi: 10.1523/jneurosci.0303-19.2019.