With aisle after aisle of colorful squeakers, balls, ropes, and stuffies, it’s hard to figure out exactly which toys will make your dog go gaga.

But researchers at the University of Bristol’s Veterinary School seem to have figured out the formula for the perfect dog toy.

The study, which is published in the distinguished animal behavior journal Animal Cognition, reveals the science behind why some toys become Fido’s favorites while others collect dust in the toy box.

The answer may lie in the habits of the domestic dog’s closest ancestor — the wolf.

“Because we think that dogs perceive toys in the same way that wolves perceive prey, they prefer toys that either taste like food or can be torn apart,” study co-author and University of Bristol Veterinary School researcher John Bradshaw told Discovery News, “however the latter can cause health problems if the dog accidentally swallows some of the pieces.”

Researchers presented dogs with a different toy for 30-second intervals until the dog stopped interacting with that toy, indicating that the dog’s interest had waned. The team used a wide variety of toys in different colors, odors, and materials, and made sure that each successive toy was a unique one that presented a contrast from the toy that came before.

The research team used Labrador Retrievers in their study, not only because of their status as one of the world’s most popular dog breeds, but because of their playful reputation. “We had to be sure that the dogs we studied would play with the toys for a few minutes at least,” Bradshaw explained, “otherwise we couldn’t have measured what would get them playing again once they’d lost interest in the original toy.”

While there was no single characteristic that made one toy preferable over another, the study revealed that as a dog gets used to the stimulus qualities of the toy — its smells, texture, and sounds — the dog is likely to grow bored with that toy.

Most of the new toys presented by researchers seemed to incite intense but temporary interest in the Labs, the researchers say, perhaps because it is instinct for canines to investigate unfamiliar items.

Co-author Anne Pullen of the University of Bristol research team explains that the perfect toys should be “soft, easily manipulable toys that can be chewed easily and/or make a noise.”

“Dogs quickly lose interest in toys with hard, unyielding surfaces, and those that don’t make a noise when manipulated,” Pullen added.

Because dogs can quickly become habituated when it comes to toys, the best thing an owner can do to spark interest in their pooch is to get involved and play, too.

“For an animal as social as a dog, toys only become really excited when they are part of a game with a person,” Bradshaw explained. “Few toys will sustain a dog’s interest for long if the owner is not around to offer encouragement.”

The researchers all agreed that dogs make such wonderful companions because they never lose the desire to play, even as adults. Many other animals only engage in play when they are young and grow out of the behavior as they age — but not the domestic dog.