As the planet warms, cold-blooded animals will have trouble adjusting. According to a study by two biologists, cold-blooded animals, which cannot regulate their internal temperatures, will struggle with climate change.
The biologists, Alex R. Gunderson and Jonathon H. Stillman from the University of California, Berkeley and San Francisco State University, analyzed 230 cold-blooded species from 112 published studies on plasticity – or the ability of animals to modify their thermal tolerance when they experience new environmental temperatures. They found that cold-blooded animals have an particularly tough time adjusting and that on average most aren’t flexible to warming climate changes.
“Overall, we found that even though all of the animals have some plasticity, they all have relatively low levels of plasticity. As environmental temperatures rise due to global warming, the animals will get closer and closer to their thermal limits, and plasticity won’t do much to help them.”
Gunderson and Stillman discovered that the plasticity of animals differs based on their habitat. So cold-blooded species like lizards and insects have less plasticity than fish and crustaceans, and thus will have a more difficult time surviving in the changing climate. Gunderson explains:
“The difference between terrestrial and aquatic animals is that the aquatic ones have a higher capacity to adjust, but it is still relatively low. Ideally, if temperatures went up three degrees, the animals’ tolerance would go up three degrees as well. But that’s not what we see.”
The study’s analysis suggests that certain animals – such as lizards, insects and snakes – can’t depend on plasticity. Rather, they will have to rely on behavior modifications, like moving to greater altitudes or more shaded habitats. But unfortunately, not all animals live in regions where such behavioral adaptations are feasible and in those cases, the species will have to evolve higher tolerance for the heat in order to survive.