How global warming is changing reptiles sex and reproduction

Barcelona: As global temperatures soar, scientists are discovering that the climate crisis is not only transforming habitats — it’s reshaping life itself, right down to the way animals reproduce.

Two new studies reveal that extreme temperatures not only reshape global climates but also directly alter how species reproduce, raising critical questions about the future of biodiversity under climate change.

Researchers from the Autonomous University of Barcelona in Spain examined two reptile species and found strikingly different responses to high heat. In one case, climate stress strengthened the species’ ability to adapt, while in the other, it triggered extraordinary biological changes, including “sex reversal.”

Published in PLOS Genetics, the first study focused on Guibe’s ground gecko (Paroedura guibeae), a lizard native to Madagascar. Under extremely hot conditions, the gecko exhibited higher rates of genetic recombination — the reshuffling of DNA that enhances genetic diversity. Scientists also observed DNA fragmentation and chromosomal changes, showing that temperature can influence not just gene activity but also how genetic information is passed through generations.

“This study helps us understand that global warming not only affects the climate, but also influences the adaptation mechanisms of animals to survive,” said co-author Laura Gonzalez Rodelas of the Autonomous University of Barcelona.

The second study, published in GigaScience, examined the central bearded dragon (Pogona vitticeps) from Australia. Known for its ability to undergo temperature-induced sex reversal, this species can transform genetic males (ZZ) into functional females if eggs are incubated at high temperatures.

Researchers say that sequencing the dragon’s genome provides crucial insight into the genes controlling sex determination and highlights how environmental stress can redefine core biological traits.

“This new genome will be a fundamental resource in facilitating and accelerating research on the reproductive particularities of this species,” said study co-author Laia Marin Gual.

Together, the two studies highlight a growing concern: climate change is not only driving species to migrate or face extinction due to habitat loss — it is also reaching deep into the biology of reproduction itself.

With heatwaves intensifying and greenhouse gas emissions continuing to rise, scientists warn that we may see more cases of temperature-driven reproductive disruption across the animal kingdom. Understanding how species respond — whether by adapting or faltering — is crucial for predicting the future of global biodiversity.

“These reproductive shifts show just how deeply climate change is intertwined with the fate of species,” said Gonzalez Rodelas. “It’s not just about where animals can live — it’s about whether they can continue to exist at all.”