Wag the dog

The tale of the wagging tail

Tony LaRoche

Dogs wag their tails. It’s the classic way we tell if Fido is happy. But does that behavior separate your mutt from a wolf or a coyote?

Kate Fish, a University of Rhode Island junior majoring in anthropology and biology, is testing that theory as she investigates a new method to morphologically distinguish domestic dogs from wild canids, the family of dogs that includes domesticated dogs along with wolves, coyotes, foxes and jackals.

“As it stands now, the literature is focused on cranial remains of these animals and using cranial and dental morphology to determine what makes a domestic dog different from wild canids,” says the Clifton Park, NY, resident. “I’m trying to find a distinguishing feature to use for the postcranial skeleton.”

Fish is one of 14 undergraduates to earn summer fellowships from the URI College of Arts and Sciences. In its second year, the fellowship awarded about $25,000 in grants supporting about 2,300 hours of research in disciplines from computer science to chemistry, anthropology to English, and film studies to criminology. (See below for a list of this summer’s recipients.)

This is Fish’s second summer fellowship for the project, and it has enabled her to spend summer break at the American Museum of Natural History in New York City, examining the skeletons of domestic and wild canids, comparing the bones that play a part in tail posture and tail wagging.

The story of modern dogs is a hot topic, says URI Anthropology Professor Holly Dunsworth, Fish’s faculty mentor. While there is some scientific debate on the origins of modern dogs, it’s commonly agreed that they were domesticated about 40,000 years ago.

“Dogs are a major factor in human evolution,” says Dunsworth. “We co-created each other, in a way. It’s not just that we domesticated them. They’re the earliest domesticated animal. And they were involved in their own domestication. It wouldn’t have happened without them being open to working with us.”

To determine whether a canid skeleton was a domesticated dog, researchers have turned to genetic data, along with the examination of the canid’s skull and teeth. But Fish’s study on postcranial identification would add a new tool for researchers at archaeological sites who come across a canid skeleton that is missing its skull, or it could supplement cranial analysis.

“According to the published literature,” says Dunsworth, “Kate’s the first person to investigate a link to tail behavior.”

Fish became interested in bones in her early teens after watching the TV show “Bones,” a crime drama about a forensic anthropologist. It started her thinking about the complexity of the human skeleton. 

“When I’m working in a room full of skeletons,” she says, “I feel like I am right where I am supposed to be.”

That fascination with bones forged a bond with Dunsworth and sparked Fish’s research in canid skeletons.

Fish was working as a research assistant for Dunsworth a couple of years ago when crews cleaning the attic in Ranger Hall on the Kingston campus uncovered a cache of animal skeletons. 

Fish’s job was to clean the skeletons, identify them and prepare them for proper storage. But many of the skeletons were missing their skulls.

“The head is the easiest way to identify an animal,” says Dunsworth. “If you have the head of a dog, you know you have a dog. If you have the head of a wolf, you know you have a wolf, or a pig, or whatever.”

Among the postcranial skeletons was a canid. Lacking its head, Dunsworth and Fish could not determine if the skeleton was from a domesticated canid. That got them thinking. How else could you determine if it was domesticated? What distinguishes a wolf or coyote from Fifi?

“I started thinking about tail wagging as a habitual behavior in domestic dogs,” says Fish. 

“While wolves do wag their tails, it is not a habitual behavior as it is for domestic dogs, who are constantly communicating this way in their lives with humans. This habitual behavior throughout a dog’s life could influence the development of the skeleton just as habitual tennis playing from a young age will influence the morphology of the racquet-wielding arm.”

To test the theory, Fish identified the muscles involved in tail posture and wagging and where those muscles attached to the skeleton (the pelvis, sacrum and caudal vertebrae). She designed measurements to compare differences in those areas in domesticated and wild canids.

This summer, Fish measured the bones of 87 skeletons from seven canid species, following up similar work last summer at the Harvard Museum of Comparative Zoology. She’s looked at skeletons, large and small – multiple dog breeds and wild canids from wolves to foxes – to make allowances for size. 

She’s also examined skeletons for signs of osteoarthritis, following an assumption that domestic dogs could be prone to arthritis from habitual tail wagging.

At the same time, she is doing preliminary analysis using Excel to run statistics and create graphs to visualize differences. This fall, she will take a high-level statistics course to learn how to analyze the data using a coding language.

“I still have a lot of data to analyze,” says Fish, “but with what I have done so far, I am seeing marginal differences in the bone anatomy that could verify my belief about tail wagging. I am still working on the significance of these differences.”

If her theory plays out, Fish plans to write a research paper and submit it for publication, and eventually her research could lead to behavioral research to further support the theory.

Growing up, Fish didn’t have a dog. She wanted one so badly, she says, she again lobbied her parents after her sister went off to college. But she’s had to make do with friends who have dogs.

“Now that I’m studying them,” she says, “I find myself watching how their tails move and thinking about their evolutionary history.”