Dogs have long been go-to subjects for researchers studying certain human diseases. Many of the techniques used in medicine today were first developed in canines: The success of bone marrow transplants, for instance, which provide new stem cells for patients suffering from blood cancers like leukemia and lymphoma, were initially borne out of preclinical trials on dogs.

According to a 2007 article in the journal Veterinary and Comparative Oncology, dogs replaced mice in bone marrow transplantation research because of their “random-bred nature, large body size, longer life span, wide genetic diversity, and well-mixed gene pool.” Dogs are the only other mammal to have that particular mix of features.

The genetic differences between many animals and humans are quite small, which is why aging researchers and companies often use mice in laboratory trials. Yet mice live for about two years, so aging-related diseases often need to be induced for research purposes. Dogs, on the other hand, develop age-related diseases over time without any coaxing. They also absorb drugs in a way that’s virtually identical to humans.

“Dogs have a lot of potential to inform human health that’s simply not available to many other species that we work with,” says Kate Creevy, a veterinarian and the chief veterinary officer on the Dog Aging Project. “They get a number of diseases spontaneously that are identical to diseases in people. You can learn how to deal with that disease in a dog, and then export that therapy to people.”

A good example of this type of translational therapy happens at Colorado State University’s Flint Animal Cancer Center. There, veterinarians sometimes work arm-in-arm with oncologists treating human patients. According to Rodney Page, DVM, a veterinarian and director of the Flint Animal Cancer Center, the sorts of cancers that dogs get — skin cancer, breast cancer, lymphoma — mimic the cancers that humans develop.

“Dogs’ cancers are sometimes as complicated under the microscope as human cancers are,” Page says. “What we’re beginning to find is that we can investigate questions in companion animals that are not only good for them, but also affect people.”

“I suspect that if we demonstrate a benefit in dogs, somebody will do research in people.”

The Golden Retriever Lifetime Study, run by the Morris Animal Foundation, has enrolled some 2,900 pet golden retrievers in every state of the continental U.S. The youngest dogs in the study are three, while the oldest are seven. There’s no sort of intervention in this study; owners don’t give their dogs any special medication or change up their daily routines. Instead, the foundation is capturing as much data as it possibly can. Owners fill out detailed, 200-question surveys every year to catalog things about the dogs’ home environments, food, behavior, and genetics, the last supplied in the form of biological data — blood, stool samples, and the like — contributed by the dogs’ family vets.

By the end of the study, the foundation will have nearly 5 million data points. Already, an in-house epidemiologist at the foundation is planning to publish three papers on the causes of death in younger golden retrievers, unusual cancers that arise in younger retrievers, and salient behavioral characteristics in young retrievers.

“The aging stuff is going to take a while because we don’t have enough old dogs yet,” says Kelly Diehl, DVM, the foundation’s acting vice president for scientific programs. “But there are things we could learn from dogs that could extend our lifespan and also the quality of life.”

In the Dog Aging Project so far, researchers have seen improvement in cardiac function with no evidence of side effects after 10 weeks, which was the first phase of the overall study. Cardiac function will be monitored in a second phase, along with activity and energy levels via GPS trackers embedded in dogs’ collars. Phase three, which Kaeberlein says could begin as early as late 2018, will feature a 10,000-dog longitudinal study, similar in nature to the golden retriever study being conducted by the Morris Animal Foundation. Of that group, 600 dogs will partake in a blind, placebo-controlled clinical trial. In mice, rapamycin sometimes leads to a 25 percent increase in lifespan, defined in this case as healthier functioning even with age. Kaeberlein and Creevy are looking for the same effect in dogs.

“It’s fairly obvious to anybody who looks at it that if this drug has a benefit in dogs, it is reasonable to imagine that it has a similar benefit in people,” Creevy says. “I suspect that if we demonstrate a benefit in dogs, somebody will do research in people.”