Tuatara tops for long life and graceful aging in new international study

New Zealand’s tuatara has emerged as one of the longest living reptiles in a new international study of cold-blooded critters.

“Tuatara can live for an impressive 137 years—a feat humans can only aspire to,” said Nicky Nelson, a co-author of the study and professor of conservation biology at Te Herenga Waka—Victoria University of Wellington.

The research, published in the journal Science, compared the aging rates of 77 cold-blooded, four-legged reptiles and amphibians.

Compared with the 137-year life span of tuatara, the study found turtles live for about 39 years, crocodiles for 21, salamanders for 10, and frogs for eight years.

“Once tuatara are of adult size, they are very slow to age. However, not every individual gets the chance to survive to a ripe old age—especially those exposed to threats from rats and other introduced predators,” Professor Nelson said.

Data on the tuatara come from a 60-year study of a population of the reptiles on North Brother Island, a small rocky island in Cook Strait.

Professor Nelson said gathering the data involved a huge effort by researchers, including nights spent searching for the tuatara and catching them by hand.

Findings of the international study may help researchers understand the aging rates of New Zealand’s other reptiles, she said.

“We have a large number of these animals, including 126 species of lizard, and we still have a lot to learn about them.”

Results suggest the rate at which reptiles age increases with mean environmental temperature, an important finding given current global warming.

Long life was also associated with physical or chemical traits, such as having a shell or producing venom. The study authors found these “protective traits” enabled animals to age more slowly and live longer.

Professor Nelson said the research highlighted the importance of long-term studies, particularly for species such as tuatara that live for more than 100 years.

“We’ve studied the population on North Brother Island for decades. Several generations of researchers have contributed to the work and it’s given us one of the longest datasets used in this international comparison.”