From anxious Weimaraners to aggressive Chihuahuas: What science can tell us about dog breeds

A large dataset shows some dog stereotypes are based in reality, and others might be unfair characterizations

Detail of a chart featuring three dog portraits

Lee Lotor and Jen Christiansen

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Dogs can have wildly different personalities, which often vary by breed and size. Although individual temperament matters most, larger trends can help predict which pooch will be meek and mild and which is most likely to bite the postal worker.

The Dog Aging Project, a long-term study on canine aging, has collected data on dog behavior from more than 50,000 owners, distilling the results into scores for traits such as trainability, excitability and aggression. Owners of mixed-breed dogs reported higher average scores for fear and aggression than owners of single-breed dogs, for instance. And compared with larger dogs, smaller dogs tended to score higher for fear, aggression and excitability and lower for trainability. Understanding these patterns is key to improving the compatibility of people and their pets. “Dogs are entirely dependent on their owner,” says veterinarian Audrey Ruple of the Virginia-Maryland College of Veterinary Medicine, a collaborator on the Dog Aging Project. A mismatch can be “devastating,” but a good match can ensure dogs receive the care and affection they need.

First in a series of charts representing data from 42,941 dogs: 19,354 individuals from 56 AKC-recognized pure dog breeds with at least 100 dogs per breed; and 23,587 mixed-breed dogs. Each dot represents the mean index score for a breed, color coded by size class. This set of charts addresses different types of aggression.

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Second in a series of dog behavior charts. This set addresses fear and anxiety.
Third in a series of dog behavior charts. This set addresses energy and excitability plus trainability.

Miriam Quick, Lee Lotor and Jen Christiansen; Source: Dog Aging Project (DAP) https://data.dogagingproject.org/Index (data)

SMALL DOG SYNDROME

Dog breeds classified as toy or small have higher owner-rated scores on aggression and fear, as well as lower trainability scores. Large and giant dog breeds, in contrast, are on average the most trainable and the least aggressive and anxious. “I suspect it has to do with the way small dogs are treated as compared with large dogs,” Ruple suggests. Good behavior in a big dog is often judged as more of a necessity, whereas people may let little dogs off the hook.

OLD DOGS, NEW TRICKS

Dogs rated as more trainable tend to learn new skills more readily. They often obey “sit” or “stay” commands immediately, and they aren’t as easily distracted by interesting sights, sounds or smells. Some breeds are known for being easily taught, and mixed-breed dogs tend to get rated as less trainable than purebreds. That pattern, however, might reflect the early life experiences of mixed-breed dogs, who often are adopted from shelters or rescues and have experienced trauma, Ruple says. A purebred dog raised by a reputable breeder, however, will be primed to be comfortable around people and eager to learn.

Humberto Basilio is a Mexican science journalist covering policy, health, misconduct, archaeology and the environment. He is also a former news intern at Scientific American. His work has been published in the New York Times, National Geographic, Science, Nature, and more.

More by Humberto Basilio

Miriam Quick is a data journalist who investigates scientific, environmental, economic and cultural issues. Her analyses and storytelling have been featured by major international media outlets, including the BBC, the New York Times, Scientific American and Sentient Media. Her book I Am a Book. I Am a Portal to the Universe (Particular, 2020), co-authored with Stefanie Posavec, won the Royal Society Young People’s Book Prize 2021.

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Jen Christiansen is acting chief of design and senior graphics editor at Scientific American, where she art directs and produces illustrated explanatory diagrams and data visualizations. She is also author of the book Building Science Graphics: An Illustrated Guide to Communicating Science through Diagrams and Visualizations (CRC Press). In 1996 she began her publishing career in New York City at Scientific American. Subsequently she moved to Washington, D.C., to join the staff of National Geographic (first as an assistant art director–researcher hybrid and then as a designer), spent four years as a freelance science communicator and returned to Scientific American in 2007. Christiansen presents and writes on topics ranging from reconciling her love for art and science to her quest to learn more about the pulsar chart on the cover of Joy Division’s album Unknown Pleasures. She holds a graduate certificate in science communication from the University of California, Santa Cruz, and a B.A. in geology and studio art from Smith College. Follow Christiansen on Bluesky @jenchristiansen.com

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Lee Lotor is an independent artist, based in the western U.S., who creates digital art inspired by native North American ecosystems and wildlife. Lotor strives to increase awareness for conservation through unique and creative artwork that highlights the interconnectedness of the natural world.

More by Lee Lotor
Scientific American Magazine Vol 334 Issue 2This article was published with the title “Battle of the Breeds” in Scientific American Magazine Vol. 334 No. 2 (), p. 86
doi:10.1038/scientificamerican022026-5404j3Z8ItUDky079bJexF

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