NEWPORT — When marine mammalogist Jen DeGroot decided to teach Lea, a sea lion, to make flipper art, she was merely looking for ways to keep the Oregon Coast Aquarium resident from getting bored.

She never imagined Lea would develop her own following. But that’s exactly what happened when fellow workers at the aquarium learned of the work and began requesting their own custom prints. Before long, DeGroot and her colleagues were having trouble keeping up with the demand.

“We thought, ‘This is a popular thing. We can make money for the animals,’” said DeGroot.

Now Lea and a second sea lion named Max are earning wide recognition as featured artists in “Fur in My Paint,” a book by Tifane Grayce on animals and their art.

DeGroot came up with the idea to teach Lea to make flipper prints about two years ago.

“I worked at an aquarium where we had penguins doing foot prints,” says DeGroot. “They walked on the canvas.” And she’d worked with sea lions at other aquariums where they were trained to paint with a brush.

But she’d never known a sea lion or any marine mammal to create flipper art.

“I decided to try it with Lea,” says DeGroot.

And Lea, a 20-year-old in residence since the nonprofit opened in 1996, proved an able student.

“To this day, I think we are the only people who have trained a sea lion to do a flipper print,” says DeGroot. “Each sea lion flipper has distinctive markings just like a human finger print and it’s really neat to see the detail in the print. It is pretty unique.”

And pretty unusual, according to author Grayce.

“All of the paintings I received from sea lions and seals were produced by blowing air onto the paint or painting with a paintbrush,” says Grayce. “In fact, most of the animals that have hands-on contact for prints — usually paw prints — require the animal to be under anesthesia during their routine check ups. The trainers then take the opportunities for prints. To condition Lea to become accustomed to her flipper being held for an extended period of time probably took a fair share of fish and encouragement.”

DeGroot also taught Lea, as well as 19-year-old Max, to paint with a brush. She puts a brush in a plastic holder, slips that in the sea lion’s mouth and offers a couple of colors of non toxic paint on a palette. The rest is up to the critters.

The art is a hit in the gift shop, where a slide show lets visitors see Lea and Max at work. All proceeds from sales of the art go back to the aquarium.

“A lot of people collect these from all the places they travel,” says Candy Torney, manager of the aquarium gift shop. “People are really impressed and after seeing this, they want to go back out and see the sea lions. It touches people who might not normally be animal appreciators.”

And that’s the best part for DeGroot and her colleagues.

“The animal paints, that’s cool; that’s exciting,” says DeGroot. “What we hope is that in people seeing the animal paint, it will encourage them to want to learn more about their natural history and the environment.”