Less mating, more greens equals a longer life in reptiles

A slow pace of life, including reduced reproductive rates and a plant-rich diet, can increase the lifespan of reptiles, a new study has found.
Researchers at the Tel Aviv University collected literature on 1,014 species of reptiles (including 672 lizards and 336 snakes), a representative sample of the approximately 10,000 known reptiles on the planet.
They examined their life history parameters: body size, earliest age at first reproduction, body temperature, reproductive modes, litter or clutch size and frequency, geographic distribution, and diet.
The researchers found that, among other factors, early sexual maturation and a higher frequency of laying eggs or giving birth were associated with shortened longevity.

"There were aspects of this study that we were able to anticipate," said Professor Shai Meiri, of the Department of Zoology at TAU's Faculty of Life Sciences.
"Reproduction, for example, comes at the price of great stress to the mother. She experience physiological stress, is unable to forage efficiently, and is more vulnerable to her surroundings," said Meiri.

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, researchers said.
"We found that reptiles that were sexually mature early on were less likely to make it to old age. Live fast and die young, they say - but live slow, live long," Meiri said.

The team also discovered that herbivores - lizards with a plant-rich diet - lived longer than similar-sized carnivores that ate mostly insects.
Ingestion of a protein-rich diet seemed to lead to faster growth, earlier and more intense reproduction, and a shortened lifespan.
Herbivorous reptiles were thought to consume nutritionally poorer food, so they reached maturity later - and therefore lived longer.
Hunting may also be riskier than gathering fruits and leaves - at least for animals, the researchers concluded.
The study also found a correlation that suggested reptiles in geographically colder regions lived longer - probably due to two factors: hibernation, which offers respite from predators, and slower movement due to a seasonal drop in metabolic rate.

"Our main predictors of longevity were herbivorous diets, colder climates, larger body sizes, and infrequent and later reproduction," said Meiri.
The study was published in the journal Global Ecology and Biogeography.