An international study analyzed the reasons for the longevity of cold-blooded animals and refuted the idea that they live on average longer than cold-blooded animals. warm-blooded.
It is generally assumed that cold-blooded animals age more slowly than cold-blooded animals. warm-blooded. However, an analysis of the aging and longevity of dozens of amphibian and reptile species found that this is not always the case.
The researchers discovered that some of the species studied age more slowly and live longer than birds and mammals, while the opposite occurs with others.
The long investigation of an international team of 114 biologists who studied 107 wild populations, covering 77 species different, has found new reasons for the longevity of cold-blooded animals, details a statement signed by several universities in the US and Australia.
The scientists found that in every group of amphibians and reptiles sampled (which included frogs, salamanders, lizards, crocodiles, and turtles) there is at least one species with “negligible senescence,” a term coined in the 1990s to describe organisms that do not show signs of aging.
In this case, this means that in said species mortality does not increase and fertility does not decrease with age.
The popular ‘thermoregulatory mode hypothesis’ suggests that ectotherms (cold-blooded animals), because they require external heat to regulate their body temperature and therefore often have slower metabolisms, they age more slowly than endotherms (animals that use internally generated heat), which have faster metabolisms.
However, contrary to traditional belief, the authors found no evidence that cold-blooded animals, on average, age more slowly and live longer than warm-blooded animals.
“We found no evidence to support the idea that a lower metabolic rate means that ectotherms age more slowly,” said one of the study’s authors, Associate Professor David Miller , wildlife population ecology expert at Pennsylvania State University.
“That relationship is only true for tortoises, suggesting that tortoises are unique among ectotherms “, he added.
The team also determined that the rate of aging in cold-blooded animals depends on environmental temperature: reptiles age faster at high temperatures, while amphibians age more slowly.
Another finding of the study was the existence of a link between the physical or chemical characteristics that protect some species, such as hard shells, spines or the poison of some frogs, with slower aging and greater longevity.
The authors pointed out that the factors that most influence the rate of aging and the useful life at room temperature, the presence of protection devices, the age at which reproduction and fertility begins.
The study was published in the review Science.