New research from Queen Mary University of London shows that amphibians can shift their diets to handle rising heat. However, this coping method has its limitations.
The study is published in the journal  Scientifics Reports and it was carried out by an international team. The scientists found that tadpoles change what they eat as temperatures climb. They eat more plants and eat more food overall. This helps them deal with the heat, at least for a while. But the researchers noticed something important. As temperatures kept rising, this dietary trick worked less and less well.
This is the first time scientists have shown, through direct experiments, that a vertebrate’s ability to use food to cope with climate change has real physical limits.
The project brought together researchers from the University of Lisbon, Queen Mary University of London’s Centre for Ecology, Evolution and Environmental Changes, and the Faculty of Sciences at the University of Lisbon. Together, they studied how heat affects the growth of the Iberian spined toad. This toad is common across Portugal.
Amphibians are cold-blooded. Like fish and reptiles, they depend on the temperature around them to control their bodies. So when the environment heats up, it can badly affect how they grow, develop, and survive.
To test whether diet could help, the team collected tadpoles from the Sintra Mountains. They raised these tadpoles under different temperatures and feeding setups. This allowed them to compare how each group responded.
The results were clear. Tadpoles changed their eating habits depending on the heat.
Dr Sara Bento from the University of Lisbon led the study. She explained that the study is the first research of its kind done in vertebrates. It shows tadpoles adjust their diet based on temperature. In cooler conditions, tadpoles eat more animal-based food. In warmer conditions, they switch to more plant material and eat more overall. But she noted that this strategy loses its power as temperatures continue to climb.
Heat also significantly accelerated development. Tadpoles kept at 20°C finished their larval stage in about 30 days. Tadpoles kept at 12°C took around 177 days to do the same. That is a significant difference in growth speed.
This faster growth had a downside, though. Tadpoles raised in warmer water ended up smaller. They were also in worse physical shape than tadpoles raised in cooler water. This suggests that growing up too fast may hurt these animals later in life.
The study revealed something else, too. Warmer temperatures changed the chemical makeup of the tadpoles’ bodies. This means climate change might affect more than just growth. It could also change how these animals process and store nutrients over time.
Dr Pavel Kratina is a Reader in Aquatic Ecology at Queen Mary University of London. He is also the study’s corresponding author. He said the effects of these findings go beyond amphibians alone. The results help explain how global warming might change what cold-blooded animals prefer to eat. It could also change how these animals interact with each other. Over time, these changes could reshape entire food webs.
He added that changes in body composition could also affect how nutritious these animals are as prey. Such changes might alter how freshwater ecosystems function as a whole. Even small shifts in body chemistry, he noted, could ripple outward through the wider food chain.
The researchers say their findings matter a lot for conservation efforts. This is especially true in Mediterranean regions. Temperatures there are expected to rise sharply in the coming decades, putting added pressure on local wildlife.
One possible solution is protecting cooler spots within wetlands and freshwater habitats. These cool zones could act as safe havens. They would provide amphibians and other aquatic animals a place to escape extreme heat as the climate keeps changing. Without such refuges, researchers warn, many vulnerable species could struggle to adapt in time.
