Running a petting zoo isn't about making money for John Phillips, co-owner of the Potomac-based petting zoo called Squeals on Wheels — it's about making people happy.

The petting zoo — which travels to many locations in Montgomery, Fairfax and Arlington counties, as well as Washington, D.C. — is a run by John and is wife, Jill.

The couple, who have each spent more than 20 years in the Army, said they are making up for years of not having any pets.

"When we first got married, Jill said she wanted a cow," John said.  "I said, 'We can't have a cow. We're in the military.'"

The Phillips had five children and two dogs when they moved to Potomac in 1997, but it didn't take long to expand the number of animals in the family.

Jill said she first bought alpacas to help trim the grass in their yard. Soon after that, the family purchased miniature horses for their children at Christmas and inherited seven miniature goats as a gift. The collection of pets kept growing up and now includes cats, farm animals and exotic reptiles.

John said their strangest pet so far is a frilly dragon — a reptile with a large flair around its neck and a wide-open mouth that is known for running on its hind legs across the floor of the jungle. John said their frilly dragon, which lives on crickets and grub worms, has mellowed out and doesn't flair up that much anymore.

When expenses for feed and medical bills began to add up in 2006, the family decided to make a profit from the collection of animals and start a petting zoo.

Jill said the inspiration for the name Squeals on Wheels came from their pet pig Benny, who would squeal with delight whenever the car pulled up in the driveway.

Squeals on Wheels visits many children's birthday parties; however, they also visit schools and nursing homes.

A lack of transportation didn't stop Squeal on Wheels from visiting assisted living facility, Arden Courts of Potomac last October. The day Squeals on Wheels was scheduled to visit, the vans were all being used, so Jill packed rabbits, ducks, chickens, a miniature horse, a miniature goat, and an alpaca into her Toyota Solara convertible and made her way to the facility.

Arden Courts senior program service coordinator Heather Mullican said she remembered the sight of the car full of critters and the impression it made on the residents of Arden Courts.

"It was rather comical. The little horse made a huge hit," Mullican said. "The residents loved them."

Squeals on Wheels also does free shows for charitable causes in the area, such as the Cabin John Volunteer Fire Department's Open House in October. John and Jill's daughter, Marlena is a volunteer EMT at Cabin John Volunteer Fire Department.

"The petting zoo was great for the kids because the fire truck lost their interest after half an hour," said Cabin John volunteer firefighter Jason Goldberg.

The Phillips said their future plans for Squeals on Wheels include expanding their reptile collection for school visits and adding horse-drawn cart rides.

The Phillips said their busiest seasons are autumn and spring, but they also do indoor parties in garages during the winter. John said to schedule a weekend event, it is necessary to call about two months in advance.

"In September and October, everybody calls up and I have to turn so many people away," he said.

The Phillips said you wouldn't expect to find a place like theirs in Potomac, but they enjoy their unusual two-acre farm.

"We have good neighbors," John said.