Given the illegal nature of organized dogfighting—a felony in all fifty states—you might think dogfighters would never risk bringing one of their dogs to a veterinarian. But you’d be wrong. A winning animal can be worth thousands of dollars, making it just too valuable to lose to its injuries.

Experts estimate tens of thousands of people are involved in dogfighting across all regions of the United States. Contract matches between dogs, and the illegal gambling alongside them, pay large stakes. And there are even dogfighting studbooks, with winners of three or more fights commanding hefty fees for breeding or pups. “It’s a very lucrative business,” said Nida Intarapanich, V16, who conducted groundbreaking research about dogfighting and animal abuse with associate professor Elizabeth Rozanski and clinical associate professor Emily McCobb, V00, VG02, while a student at Cummings School. “And participants are very good at covering their tracks,” she said, noting that dogfighters often give a fake history of a “yard accident” to explain animals’ injuries, should they be noticed.

In December 2017, Intarapanich and her fellow researchers from Tufts and the ASPCA published a study in the Journal of the American Veterinary Medical Association that provides veterinarians the first guidelines aimed at distinguishing wounds caused by organized dogfights from those caused by everyday clashes between pets. “Our study not only serves to inform veterinarians about the clandestine world of organized dogfighting but also provides evidence-based research to assist veterinarians in recognizing dogs that may be victims of this criminal activity,” said veterinarian Rachel Touroo, senior director of ASPCA Veterinary Forensic Sciences and coauthor of the JAVMA article.

For the retrospective study, the researchers characterized injuries found in 196 dogs involved in spontaneous fights—often with another dog in the same household or a dog belonging to a friend or neighbor—resulting in a visit to the veterinary emergency room. They then compared these patterns against the injuries documented in 62 dogs seized during criminal investigations of organized dogfighting.

The researchers found that dogs involved in organized dogfighting tended to have multiple wounds clustered in the same locations: the front legs, the head and muzzle, and around the neck and chest. The findings align with jargon in underground dogfighting literature. “It has become popular among breeders in the dogfighting business to select for animals that target specific parts of other dogs’ bodies during fights,” Intarapanich explained. “There are essentially newsletters where you’ll find classifieds advertising ‘head dogs,’ ‘chest dogs,’ or ‘leg dogs’ for sale or stud.”

The study found that dogs injured during spontaneous fights generally had fewer wounds and that the wounds were not concentrated in the same regions of the body. This is likely because “spontaneous fights between dogs are highly ritualized,” Intarapanich said, with participants aiming to compel submission rather than cause injury. Signs of submission, such as turning away or rolling over, generally end these fights. Dogs used in organized fighting, on the other hand, are bred and trained to ignore these cues and continue to attack. “Dogs involved in spontaneous fights also tend to inhibit their bites in a fight,” Intarapanich said. “It is rare to find puncture wounds that are the full depth of a canine tooth.” In contrast, dogs involved in organized fights can bite so hard that their teeth can get stuck in the other dog—leading to tooth injuries from forced removal via a “bite stick.”

In their study, the researchers also characterized injuries found in smaller dogs that were involved in spontaneous fights with a larger dog. These occurrences, often referred to as “big dog-little dog” (BDLD) fights by veterinarians, had not been previously described in veterinary literature either, despite being relatively common. As veterinarians in clinical practice were more likely to be familiar with the injuries caused by BDLD fights, this group of dogs was included in the study to demonstrate the validity of the methods used, by describing a pattern of injury for these fights that was consistent with what veterinarians typically observe. “Generally, the big dog sees the little dog as prey, so it grabs the little dog and shakes it,” Intarapanich said. “The injuries often seen with this kind of attack include external wounds around the midsection of the smaller dog as well as internal and retinal injuries similar to what we see with shaken baby syndrome in humans.”

In addition to helping veterinarians recognize situations that may warrant reporting a suspected dogfighter to the authorities, the study provides a new tool to help aid law enforcement in prosecution. “Illegal dogfighting is still pervasive throughout the U.S.,” said Touroo of the ASPCA, and the interstate movement of dogs for fighting purposes is a felony. In addition to being animal abuse, dog fighting is considered a serious criminal activity because of its association with illegal gambling, organized crime, illegal firearms, drug dealing, and other forms of violence.

“Unless law enforcement officers interrupt an organized dog fight or get it on video, they generally must rely on circumstantial evidence—for example, finding veterinary paraphernalia that a breeder maybe shouldn’t have—to prosecute this crime,” Intarapanich said. “With this study, we are hoping to provide research to help demolish the common excuse of a ‘yard accident’ for injuries on fighting dogs.”

Genevieve Rajewski, the editor of Cummings Veterinary Medicine, can be reached at genevieve.rajewski@tufts.edu.