Science shows that interacting with animals may have big health benefits. Pets can help lower blood pressure and cholesterol, increase the amount of exercise people get and decrease stress. Now, a new study finds that animals also may significantly increase positive social behaviors in children who have an autism spectrum disorder.

"The presence of animals appears to encourage social interaction among children with autism," study author Marguerite O'Haire, a PhD candidate at The University of Queensland in Australia, told The Huffington Post. "Including an animal in children's playtime or home activities may be an effective way to encourage socialization with other children as well as adults."

Ninety-nine children ages 5 to 13 from four primary schools in Brisbane, Australia -- some who were autistic and some who were not -- were monitored as they either played with toys or interacted with two guinea pigs, their classroom pets. When they were with the guinea pigs, the children with autism were more likely to talk and look at their peers than when they were with the toys, which included dolls, art supplies and Beyblade tops. They were also more open to their fellow students approaching them and were less likely to cry or whine.

"Children with autism engaged in 55 percent more social behaviors when they were with the animals, compared to toys," said O'Haire, who added that the amount they smiled more than doubled.

"These are big improvements for children who struggle to interact socially and often suffer from heightened anxiety and stress," O'Haire said. "The ability of an animal to bring out a smile or get a child talking was a huge finding." Children with autism, which affects one in 88 children in the U.S., often struggle with social interaction and behavior.

The guinea pigs in the study were not trained therapy animals and were chosen simply because they make good classroom pets. Animal therapy differs from animal exposure in that it has clear goals and is led by trained practitioners, typically psychiatrists or psychologists. The current study, published in the journal PLOS ONE on Wednesday, looked at whether merely interacting with an animal could change children's behavior.

"It's a really young area," said Dr. Melissa Nishawala, an assistant professor with the Child Study Center at the New York University Langone Medical Centert, referring to animal-assisted therapy. It has been around for several decades, but the past five years have seen a "real uptick" in research looking at the possible health benefits tied to human animal interaction, she said.

"Anecdotally, we can say many kid with autism are interested in animals. They seem to have a real affinity for them; they often enjoy their company and they may be described by their parents as much calmer, more engaged and happier in general when they're around an animal," Nishawala said. What it is about the interaction that's beneficial is not yet clear.

The National Institutes of Health has expressed an interest in funding studies that examine human-animal interaction, putting out a call for investigations that focus specifically on child health and development in 2010. The advocacy group Autism Speaks has awarded several grants to investigators studying equine therapy, or the use of horses to help improve children's social behaviors and their motor skills, while other studies have looked at dogs. Earlier this month, a small review published online in The Journal of Alternative and Complementary Medicine concluded that the results of six studies looking at what happens when children with autism interact with dogs are "encouraging," but that more research is needed.

"I think it's a little preliminary," said Lauren Elder, assistant director of dissemination science with Autism Speaks. The new study "focused on children who were included in typical education classes. Most were likely quite high functioning, so it's not necessarily representative of the entire spectrum," she said. Further, the study focused on the social behaviors when children were in the presence of the animal. It is not clear whether there could be a longer term effect on the their social development.

Experts say that parents who have thought about getting a pet or who have noticed that their child seems to enjoy being in the presence of animals might want to consider it. But getting a child with autism a pet will not magically improve their symptoms, and pets are not for everyone.

"I think it's something for families to think about, how it might fit into their child's life," said Nishawala.