COLUMBIA, SC — A grandfatherly man wearing a baseball cap and glasses shuffles into the kangaroo exhibit at Riverbanks Zoo and Garden, slowed only slightly by aching, 92-year-old knees.

He plops down what looks like a long-handled dust pan and uses a small rake to push a pile of marsupial poop into it. Then he moves on to the next pile and does the same thing.

Jack Bonturi has been volunteering to do what appears to be thankless labor for 30 years. To him, it’s not drudgery. He makes it fun.

“I get paid by the pound,” Bonturi jokes. Of course, like all zoo volunteers, he isn’t paid anything.

“Don’t reveal any of my secrets,” he tells a reporter jotting down his comments.

His secret, however, is obvious to anyone who watches Bonturi in his four-day-a-week volunteer “job.” He likes to work and thrives on routine. It helps that he gets to be around animals and that he’s providing a service that allows the paid animal keepers to spend more time tending to the animals’ other needs.

“He loves helping people,” says Grace Scurry, Bonturi’s daughter.

Bonturi, whose formal education ended at sixth grade during the tough Depression years, got his first paying job at age 14. He’s been working ever since, first with his father for a shoe company in Pennsylvania, later in his native New York City. He spent a little time in South Carolina after visiting the state with a friend whose family lived in Columbia.

After serving in the Air Force during World War II, Bonturi came south to stay. At 34, he was content with his bachelor’s life. Then an appendix problem landed him in the old Columbia Hospital, where he met a pretty nurse named Lily Matthews.

She later told him the first day he was in the hospital she told the other nurses that she had met the man she was going to marry. Three months later, they were hitched.

Bonturi turned his experience in the screen-print industry into his own company, Central Advertising, at the corner of Jackson Boulevard and Devine Street. He and Lily raised three children. He sold the business and retired in 1982.

“I spent about a week or two at home, and that didn’t cut it,” Bonturi says. “When you retire if you don’t find something to do, it’s terrible. You go from the armchair to the refrigerator to the television so many times.”

He and Lily had a zoo membership and received the Riverbanks Society newsletter, which had a notice asking for volunteers.

He signed up in 1982, and he’s never stopped.

“I arrive in the parking lot at 7:30 in the morning, read the newspaper for 30 minutes, then go to my job at 8,” Bonturi says. “Notice I said ‘job.’ That’s what I consider it. I’m not just a volunteer.”

He typically works until 11 a.m., and he insists on putting in some effort.

“If you pick up the shovel and try to help him, he says, ‘Are you trying to take my job,’” says Sue Pfaff, Riverbanks’ assistant mammal curator. “If anything, we have to slow him down. I think the zoo is his medicine.”

Bonturi not only inspires those around him, he satisfies their sweet tooth. The other hobby he picked up in retirement was baking cheesecakes, and he apparently excels at it.

“We’re always telling him he needs to open his own cheesecake shop,” Pfaff says. “He does all this stuff for us, and then he brings us cheesecakes. It’s not right. Shouldn’t we be bringing cheesecakes for him?”

Bonturi has been a presence at the zoo longer than most of the keepers.

Riverbanks president and CEO Satch Krantz, who has been at the zoo since 1973, is one of the few on the staff with a longer tenure.

“Jack is very special to Riverbanks,” Krantz said. “He represents the best of the 125 active volunteers who contribute each and every day to the success of the zoo and garden.”

At first, the zoo asked volunteers only to observe animals and let the keepers know what they saw. Even during that period, Bonturi went beyond the normal duties. He helped raise three siamangs whose mother wouldn’t feed them. He helped the keepers cut fish and insert medicine in them for the sea lions.

He was one of the first volunteers allowed to do manual labor, and years later he has scooped poop and washed out structures in nearly every corner of the zoo.

“I’m an expert on poop,” he says. “I have five cats at home.”

At the zoo, the elephants are among his favorites. A constant teaser himself, he laughs when the golden lion tamarins sneak up and steal his glasses while he hoses down their home.

He used to work three mornings a week. He slowed a little for awhile to spend extra time with Lily as her health deteriorated. After her death in 2011, he asked to work more, going to four days a week. He’s a regular now on Mondays, Wednesdays, Fridays and Saturdays. He shows up on most holidays, helping out when the keeper staff might be short-handed.

“If he didn’t have the zoo, I don’t know what he would have done,” says his daughter. “He wants to keep moving. He feels like if he stops, he’s going to fall apart.”

Truth is, age is beginning to take its toll. His knees are telling him to cut back. His heart says otherwise.

“He doesn’t want to stop, and I don’t want him to stop,” Scurry says.

Bonturi suspects his friends at the zoo might be secretly helping him cut back on the manual labor. He once spent most of his time with the elephants, hippos and giraffes. Those are big-bucket creatures, as opposed to the small buckets needed to pick up after the creatures on his current route – kangaroos, lemurs and babirusas.

The babirusas, “that’s where it’s real work, because they’re pigs,” he says.

The zoo has given him several awards, including volunteer of the year. He wears a “Star Volunteer” pin on his cap. When he first got it, he pointed it out to the gorilla keepers and told them, “every time you’re in my presence and see this badge, you’re supposed to bow down,” he says. “But they’ve never done it.”

Even though he jokes every day about quitting or getting fired, he plans to keep showing up as long as his knees will let him.

“I volunteered to take Satch’s place,” Bonturi says, “but he’s holding on too long.”