A slow pace of life, including reduced reproductive rates and a plant-rich diet, can increase the lifespans of lizards and snakes

Less sex and eating more greens has been found to lead to a longer – if not necessarily more enjoyable – life in reptiles.

Researchers discovered that a slow pace of life, including reduced reproductive rates and a plant-rich diet, can increase the lifespans of lizards and snakes.

An international team, including scientists from the University of Lincoln, the US, Malaysia, Ecuador and the Middle East examined studies on more than 1,000 species of reptiles, including 672 lizards and 336 snakes, chosen to represent the approximately 10,000 known reptiles on the planet.

After examining ”life history parameters”, such as body size, earliest age at first reproduction, body temperature, diet, litter size and frequency and geographic distribution, they found that among other factors, early sexual maturation and a greater frequency of laying eggs or giving birth were associated with shortened longevity.

Professor Shai Meiri, from Tel Aviv University, who led the study, said: ”There were aspects of this study that we were able to anticipate. Reproduction, for example, comes at the price of great stress to the mother.

”She experiences physiological stress, is unable to forage efficiently, and is more vulnerable to her surroundings. This reflects evolutionary logic.

”To relate this to humans, imagine the physical stress the body of an Olympic gymnast experiences – and the first thing that disappears is her period. In reptiles, it also increases the probability of being preyed upon.”

Reptiles that were sexually mature early on were also less likely to make it to old age. Prof Meiri said: ”Live fast and die young, they say – but live slow, live long.”

The scientists also discovered that herbivorous lizards, with a plant-rich diet, lived longer than smaller carnivores that ate mostly insects.

A protein-rich diet seemed to lead to faster growth, earlier and more intense reproduction and a shortened lifespan. Herbivores were thought to consume nutritionally poorer food, so reached maturity later and therefore lived longer.

Hunting was also found likely to be riskier than gathering fruits and leaves, at least for animals.

Prof Meiri said: ”If you’re an animal, hunting your food can be dangerous. You risk injury or even death. This is why you cannot simply transfer this logic to humans.

”Going to buy a head of lettuce at the supermarket is just as risky as going to the meat department. As a reptile, if you eat plants, you may need to be frugal, take life more slowly, and save your calories for digestion. You are forced to have a slower life, a more phlegmatic existence.”

The research also suggested that reptiles living in colder regions live longer, due to hibernation, which offers safety from predators, and slower movement due to a seasonal drop in metabolic rate.

Prof Meiri said: ”Our main predictors of longevity were herbivorous diets, colder climates, larger body sizes, and infrequent and later reproduction.

”I stress that you cannot simply transfer the results of a study on lizards to humans – but this is the first study of its kind on reptiles, which does open up an avenue for further research on other factors that lead to longevity of these and other species.”

The research was published in the journal Global Ecology And Biogeography.