Redefining life expectancy and maximum lifespan for wildlife management

October 14th, 2020

A freshwater crocodile lying on a large rock.

The maximum recorded age of an individual Freshwater crocodile is 60 years. Our modelling suggests that in the wild most Freshwater crocodiles only live to 53 years of age. This information can be used to better manage wild populations. Credit: Heather Paul, CC BY-ND 2.0.

FSP early career researcher, Ben Mayne, has developed a statistical method to estimate the life expectancy and maximum lifespan of wild animal populations.

“Predicting lifespan for wild animals is difficult, especially for long lived species that may outlive a generation of researchers,” says Ben.

“Scientists commonly use an animal’s oldest recorded age as the species maximum lifespan. But animals in captivity are known to live longer than in the wild. Using life expectancy and maximum lifespan values based on animals in captivity may not be applicable to managing wild populations,” he says.

In this study the researchers used the ages of multiple individual animals in a population and applied a statistical modelling method to define a population specific life expectancy and maximum lifespan. Their approach has similarities to what is used in human populations, and if applied should provide a more effective way to evaluate the robustness of wild animal populations to environmental change and to harvest.

You can read more on this method in their recently published paper in Austral Ecology.