People at the University of Colorado Boulder thought Leslie Leinwand had lost her mind when she decided to start studying snakes nearly 20 years ago.

It was a research paper that sparked her interest in pythons’ biology and what studying them could mean for developing new treatments for human heart disease. Leinwand is a professor and the chief scientific officer of the BioFrontiers Institute at CU Boulder.

“I read that and literally that same day I went down to the lab and I said, “OK, we’re going to start working on pythons.’” Leinwand said. “And people thought I had lost my mind, honestly.”

Leinwand now leads one of the few labs worldwide that studies pythons to improve human health. She and her team are discovering new biology and generating data nobody’s ever seen.

“Not a lot of people work on pythons,” Leinwand said. “Usually we work on mice and rats and flies and other organisms that are more standard. The reason that we began to be interested in pythons had to do with their extraordinary biology.”

Pythons eat infrequently and can go as long as a year or two in the wild without any food. When they do eat, they eat a large meal that could be bigger than they are, like swallowing an antelope or alligator whole. To digest the meal, the snake’s organs grow in mass and build new tissue quickly. Some organs can double in size in a matter of days.

Pythons excel at healthy heart growth during the digestive process. Leinwand’s research has shown that after a meal, the python’s heart gets much bigger, the heart rate doubles and the bloodstream turns milky white with circulating fats that nourish rather than harm their heart tissue.

“We discovered that the hearts of pythons, even when they’re fasting or fed, are much less stiff than a mammalian heart,” she said. “We’d like to understand how the snake heart becomes less stiff after it eats a meal because we think that might lead potentially to treatments for fibrotic hearts.”

Cardiac fibrosis is a condition where the heart tissue stiffens. Generally, Leinwand said, stiff hearts are sick hearts.

Post-doctoral researcher Thomas Martin said a stiff heart can’t pump or fill with blood very well, but the python has a unique ability to make its heart less stiff.

“That to me is probably the most exciting aspect … we know this is a problem in human disease and we know the python has figured out how to modify its stiffness,” he said.

Leinwand hopes the research may someday help people who have late-stage heart disease.

“If we could develop a way to activate what we call the pathways that the snake uses to make their heart beneficial, we hope we could translate that to people who really can’t get the benefits of exercise,” she said.

Leinwand seeks to understand how a python can essentially remodel its heart, and how pythons can tolerate long-term fasting while not losing any muscle mass.

Graduate student Skip Maas helps with snake care, research methods and data analysis. He said the snakes are pretty sedentary creatures and don’t move a lot.

“During that time after not eating and not moving for six months they lose next to no muscle or protein mass at all, which is incredible,” he said. “We’re looking into why that is and how they do that.”

The lab studies about 35 snakes, a mix of ball pythons and Burmese pythons. Burmese pythons are one of the largest species of snakes in the world and can be 20 feet or longer. But, the lab doesn’t work with Burmese pythons larger than six or seven feet. Ball pythons are common house pets that can be up to five or six feet long. In captivity and with proper care, both species can live for decades.

Leinwand said starting a colony of Pythons was not trivial. She sought permission from the university to work on and study snakes, and then contacted a snake breeder in Oklahoma asking to buy 15 baby pythons.

“When they arrived, they were in a pillowcase in a Styrofoam box with holes poked in the sides and I opened this box and I saw this thing of pythons all twirling around each other and I said to myself, ‘Oh, what have I done?’” she said, laughing. “And actually it’s been a really fun project to do because everything you learn is something new.”

Maas said he has a lot of fun working with the snakes, and that they’re “really cute.”

“I feel like a lot of people get pretty scared and worried about snakes but by and large they are just such cool organisms,” he said.

Martin has been in the lab for three years and works with the pythons while mentoring students. He said the potential for discovering new python biology is what excites him the most.

“They’re a model that hasn’t been studied so well and as a result, you can find things no one else has found before,” he said.