Only 1% of Turtles Get Cancer

A new study from researchers at the University of Nottingham provides the strongest evidence to date that cancer is extremely rare in turtles.

While previous research had hinted that cancer might be uncommon in turtles, the new analysis, published in BioScience, shows that only ~1% of turtles are affected, far less than in mammals or birds.

Cancer is rare in turtles, despite their size and age

Turtles can live for more than a century. Some even grow to immense sizes – Galapagos and Aldabra giant tortoises can weigh hundreds of kilograms and live well beyond 150 years.

In humans and other animals, longevity and large body size are typically linked to higher cancer risk – more cells and time usually mean more opportunities for mutations. However, turtles, it turns out, are an exception.

In the most comprehensive analysis yet, researchers have shown that cancer is strikingly rare in turtles. Drawing on decades of veterinary records and necropsy data from zoos around the world – including Chester Zoo in the UK – the team found that fewer than 1% of individuals had developed cancer, providing the strongest evidence yet that turtles are uniquely resistant to the disease.

“Turtles, especially iconic species like Galapagos and Aldabra giant tortoises, are famous for living long lives and growing to tremendous sizes,” said Dr. Ylenia Chiari, associate professor in the Faculty of Medicine & Health Science, University of Nottingham, and senior author of the study. “You’d expect that to mean more cancer, but our study, which combines decades of zoo records with previous research, shows how incredibly rare cancer is in these animals.”

Unlocking the secrets of cancer resistance and longevity

What gives turtles this apparent superpower?

The team believes the answer lies in a combination of biological factors – strong anti-cancer genes, mechanisms that protect DNA from damage and a slow metabolism that reduces stress on cells. Together, these traits may offer a natural blueprint for disease resistance and healthy aging.

“Turtles are an untapped model for understanding how to prevent or delay cancer,” said Chiari.

“Our work highlights the potential of these species to inform human medicine, and it shows the vital role zoos play in advancing science through collaboration,” she added.

Dr. Scott Glaberman, associate professor in the Centre for Environmental Research and Justice, University of Birmingham (UK), and first author of the study, added: “Biodiversity has so much to teach us about how the world works. While fascinating in their own right, extreme species like giant tortoises may have already solved many of the problems humans face, including those related to aging and cancer. That makes biodiversity doubly worthy of protection.”

Zoos play a crucial role in conservation and medical discovery

The findings would not have been possible without the contribution of detailed veterinary records collected over many years by conservation-focused zoos. Chester Zoo has been instrumental in both the care of long-lived tortoises and in the sharing of health data.

“This research underscores the immense value of zoo-based science,” said co-author Dr. Helena Turner, research officer at Chester Zoo. “We’ve long been committed to the long-term care and monitoring of our animals, and it’s fantastic to see those efforts support scientific advances that may ultimately benefit both wildlife and humans.”

Many of the zoos involved in the study are also working to conserve threatened species through breeding programs, education and habitat restoration. According to the IUCN Red List, several turtle species are endangered or critically endangered due to habitat loss, climate change and the illegal pet trade.

As researchers continue to uncover how turtles resist cancer, the hope is that protecting these ancient animals might one day lead to protecting human health, too.

Reference: Glaberman S, Bulls SE, Platner L, et al. Do turtles get cancer? Biosciences. 2025. doi: 10.1093/biosci/biaf100

This article is a rework of a press release issued by the University of Nottingham. Material has been edited for length and content.