Turtles Rarely Get Cancer Despite Living 150+ Years

Giant tortoises can weigh hundreds of kilograms and live over 150 years—conditions that should make cancer inevitable.

Yet new research reveals these ancient reptiles develop cancer at remarkably low rates, with only 1% of individuals affected compared to much higher rates in mammals and birds. The findings could unlock secrets for preventing cancer in humans.

The study, published in BioScience, analyzed medical records and necropsies from hundreds of zoo turtles across the US, UK, and Europe. Led by Dr. Ylenia Chiari from the University of Nottingham, the research provides the strongest evidence yet that cancer resistance is a defining characteristic of turtle biology.

Defying the Cancer-Size Paradox

Large, long-lived animals typically face higher cancer risk because more cells create more opportunities for dangerous mutations. This relationship holds true across most species—except turtles appear to have solved this biological puzzle.

Chester Zoo’s radiated tortoise Burt, born in 1945, exemplifies this phenomenon. Now approaching 80 years old with potential to reach 100, Burt represents countless turtle generations that have evolved extraordinary cancer resistance mechanisms.

The research team examined not just cancer incidence but also behavior. When tumors did occur in turtles, they almost never metastasized or spread to other organs—a stark contrast to cancer progression in mammals.

Clues from Ancient Survivors

Scientists suspect turtle cancer resistance stems from multiple biological advantages:

• Robust cellular repair systems that prevent DNA damage accumulation
• Slower metabolism reducing oxidative stress on cells
• Unique genetic variants that actively suppress tumor formation
• Enhanced immune surveillance detecting abnormal cells early

These mechanisms likely evolved over millions of years, as turtles survived mass extinctions that eliminated countless other species. Their biological solutions to aging and cancer represent a natural laboratory for understanding disease resistance.

Zoo Science Enables Discovery

“Turtles, especially iconic species like Galapagos and Aldabra giant tortoises, are famous for living long lives and growing to tremendous sizes,” explains Dr. Chiari. “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.”

The research was only possible through decades of meticulous record-keeping by zoos worldwide. Chester Zoo’s Dr. Helena Turner emphasizes this collaborative approach: “This research underscores the immense value of zoo-based science. At Chester Zoo, we’ve long been committed to detailed health monitoring and the long-term care of our animals.”

Co-author Dr. Scott Glaberman from the University of Birmingham adds broader context: “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.”

Conservation and Medical Connections

The timing of this discovery carries urgency. Many turtle species face extinction from climate change, habitat loss, and illegal trafficking. Several species studied are classified as Endangered or Critically Endangered, making their conservation both an environmental and potential medical imperative.

Understanding turtle cancer resistance could inform human medicine, particularly for age-related diseases. If scientists can identify the specific genes and pathways protecting turtles, these insights might translate into new prevention strategies or treatments.

The study highlights how species conservation and medical research intersect. Protecting biodiversity preserves not just ecological heritage but also biological solutions developed over evolutionary time scales—solutions that might prove crucial for human health challenges.

As researchers continue investigating turtle longevity secrets, these ancient reptiles may hold keys to extending healthy human lifespans while reducing cancer risk, proving that sometimes the oldest creatures offer the most modern solutions.