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Crocodile parenting skills could make them resilient to climate change

Crocs bury their nests in rotting vegetation or earth, which insulates them against temperature fluctuations.

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Crocodile (Australia Zoo/PA)

Crocodile (Australia Zoo/PA)

Crocodile (Australia Zoo/PA)

Crocodiles could be more resilient to climate change than other species due to their parenting skills, according to scientists.

The reptiles are one of the oldest surviving lineages on Earth, having been around for 230 million years and survived two extinctions.

Previous studies have suggested the crocodile diet, aquatic nature and behaviours could help them cope with harsh environmental conditions.

A new study published in the Biological Journal of the Linnean Society has found their unique reproductive biology and parenting decisions may also play a part in their survival.

Crocodiles, similar to turtles, have no sex chromosomes and the gender of hatchlings is determined by the temperature at which they are incubated.

The species have a threshold temperature at which the ratio of males to females is roughly equal.

A higher temperature means more male crocodiles are produced, though in turtles this results in more females.

Climate change is causing some turtle populations to become over 80% female, which could have devastating consequences, the scientists said.

But the study, which analysed data from 20 species of crocodile from across the world, found that geographical location does not affect threshold incubation temperatures.

Turtles always return to the same beach to nest and lay eggs, regardless of local environmental conditions, and leave their young to hatch alone and fend for themselves.

However, crocodiles select their nesting sites carefully and bury their nests in rotting vegetation or earth to ensure a constant temperature.

Whilst their parenting skills and other adaptations brace them for climate change, they aren’t immuneRebecca Lakin

Rebecca Lakin, a PhD student at the Milner Centre for Evolution, said: “Crocodylians are keystone species in their ecosystems.

“They are the last surviving archosaurs, a group that once inhabited every continent and has persisted for at least 230 million years.

“They show a remarkable resilience to cataclysmic climate change and habitat loss, however half of all living crocodile species are threatened with extinction and the rate of vertebrate species loss will soon equal or even exceed that of the mass extinction that killed the dinosaurs.

“Whilst their parenting skills and other adaptations brace them for climate change, they aren’t immune.

“They are still vulnerable to other human-induced threats such as pollution, the damming of rivers, nest flooding and poaching for meat or skin.

“Climate change could encourage these great survivors to relocate to other areas that are close to densely human populated areas, putting them at even greater threat.”

PA