British vets have performed the first ever heart ultrasound on a python.
The team of researchers from Cardiff Metropolitan University are measuring heart patterns in various animals as part of a study to improve understanding of the human heart.
The test was successfully carried out on Bali, the biggest snake in Europe, at Chester Zoo.
Measuring 6.6m (21ft 7in) long, Bali is a reticulated python - the longest breed in the world.
Eight handlers were required to move the snake for her health check - she weighs 90kg (198lb) and can become aggressive.
Chester Zoo's Gerardo Garcia told Sky News: "Reticulated pythons are not venomous, but they have about 100 teeth which they use to capture prey.
"They kill their prey by wrapping around them, causing asphyxiation."
Snake handler Steve Unwin added: "The team here are very experienced handling snakes and knowing what to do.
"So we're making sure everything is calm, cool and we're putting her in a position of least stress as possible."
Throughout the tests the snake's head was covered by a tube to prevent it from attacking and to keep it calm.
Eric Stohr, from Cardiff Metropolitan University, told Sky News about the heart scan.
"We have seen the heart," he said. "We're not entirely sure whether we've seen exactly what we wanted to see.
"But we're trying to look at the images now and maybe see how the heart is moving, how the blood is flowing through the heart."
The team of cardio experts have attempted similar tests on giraffes and sharks.
They say snake hearts are of particular interest because they have three chambers, unlike human hearts which have four.