What To Expect When You Adopt A Shelter Pet, According To Scientists

No dog is paw-fect – but new research says that’s to be expected.

Holly Large - Editorial Assistant

Holly Large

Holly Large - Editorial Assistant

Holly Large

Editorial Assistant

Holly is a graduate medical biochemist with an enthusiasm for making science interesting, fun and accessible.

Editorial Assistant

Dog behind fencing in an adoption shelter, close up on its nose

A very boopable snoot.

Image credit: Paradiso/

If you’re looking to adopt a new furry friend, a new study has revealed what can be expected in the first six months of owning a dog from a shelter.

Around 2 million dogs are adopted from shelters in the US each year. However, owners can sometimes be faced with unexpected changes in their new companions after the so-called “honeymoon period”. 


This phenomenon is where the full picture of a dog’s behavior is not apparent until they are comfortable in their homes. Although any changes that occur can be positive, there can also be negative behaviors, and around 15 percent of adopted dogs end up being returned to shelters.

Keeping track

Researchers from Ohio State University have produced a comprehensive study of the changes in adopted dogs’ behavior over the first six months, in the hopes that it could give potential owners a better idea of what to expect.

“The shelter system touches many lives, both humans and pets,” said Kyle Bohland, lead author of the study, in a statement

“And so it’s important for us to be able to counsel owners on what may or may not change in the future so they can be better prepared to handle those consequences and then, hopefully, keep dogs in homes.”


The research team surveyed the owners of 99 dogs adopted from five Ohio shelters between October 1, 2020 and June 1, 2021, requesting information at 7, 30, 90, and 180 days after adoption. To assess behavior in a standardized way, they used a research tool called the Canine Behavioral Assessment & Research Questionnaire (C-BARQ).

Participants were asked to answer 42 questions on a 0-4 scale, rating behaviors such as excitability; aggression directed toward strangers, owners, and either familiar or unfamiliar dogs; and separation-related behavior. They were also asked to rate their overall satisfaction with the dog’s behavior and record any changes in their household that could affect canine behavior.

Going through a ruff patch

By the end of the sixth month, it was found that there was a significant decrease in separation-related and attachment and attention-seeking behaviors – good news for those who may need to leave the house, sans dog, on a regular basis.

However, the findings also demonstrated significant increases in stranger-directed aggression, chasing behavior, and training difficulty at all time points, and there was a high prevalence of all types of aggression at various points throughout the six months.


“The biggest thing that stuck out to me was that we’ve got a lot of aggression among dogs in our community,” said Bohland. 

“That definitely concerns me from a public health standpoint and from a human mental health standpoint, because we’ve got a lot of dogs that are struggling – and that has human implications.” 

Taking into consideration factors such as a dog’s size, age, and medical history, statistical analysis revealed that some could be linked to the changes seen in behavior. 

In the case of aggression, for example, the results suggested that dogs who had received anti-anxiety medication during their time at shelters were more likely to exhibit aggressive behaviors toward strangers. This is thought to have less to do with receiving medication and more that the dogs had been difficult to handle from the start.

Staying paw-sitive

The researchers believe the changes seen can be explained. In the paper, they suggest that the increase in stranger-directed aggression may be due to dogs becoming more protective over their new environment, and a decrease in separation anxiety reflective of feeling more secure and confident.

The vast majority of owners also still believed their dogs to be pretty much 10/10 good bois – after six months, 93.7 percent rated their dog’s overall behavior as excellent or good and 100 percent believed their dogs had adjusted to their new homes extremely or moderately well.

“[D]espite [aggression], people were pretty darn happy with their dogs,” explained Bohland. 

“This combination of findings is a reminder that just about everybody has, on some level, dealt with unpredictable behavior problems, illnesses and the quirks of animal aging – and we still love our dogs. Overall, this really speaks to the bond people have with their pets.”


The study authors hope that their findings will be used by vets and shelters to provide potential owners with more accurate information on what behavior changes to expect and, in turn, give them more realistic expectations about adopting a canine companion.

“The bottom line is we don’t want to see dogs coming back to shelters,” Bohland said. 

“A lot of what we study comes from clients having questions. So my hope is that in the long term, this can help shelter employees and veterinarians target interventions that will help keep more dogs in their homes.”

The study is published in PLOS ONE.


  • tag
  • animals,

  • dogs,

  • animal behavior,

  • Pets,

  • adoption,

  • animal shelter,

  • animal adoption