Animal brains are changing due to climate change

Climate change resulting from human activities is increasingly affecting the living environment on Earth. Rising temperatures, rapid changes in precipitation and seasonality, and ocean acidification are changing the habitat of many animal species. How do animals adapt to these new and often extreme conditions?

The nervous system of animals plays a central role in enabling and limiting their responses to climate change. As a biologist and neuroscientist, two of my main research interests are understanding how animals adapt to extreme temperatures and exploring the forces that shape the structure and function of animal nervous systems, especially the brain. The intersection of these interests led me to investigate the effects of climate on the nervous system and how animals respond to rapid environmental change.

All basic functions of the nervous system (perception, mental processing, and controlling behavior) are critical. They allow animals to navigate their environments in ways that enable them to survive and reproduce. Climate change is likely to affect these functions, often for the worse.

Changing the sensory environment

Changing temperatures alter the energy balance of ecosystems, from plants producing energy from sunlight to animals consuming plants and other animals, and in turn alter the sensory worlds experienced by animals. Climate change is likely to affect all senses, from sight and taste to smell and touch.

Animals such as mammals perceive temperature partly through special receptor proteins in their nervous systems that respond to heat and cold and distinguish between moderate and extreme temperatures. These receptor proteins help animals find suitable habitats and may play a critical role in how animals respond to temperature changes.

Climate change is disrupting the ecological cues that animals use to solve problems such as habitat selection, foraging, and mate selection. Some animals, such as mosquitoes that carry parasites and pathogens, rely on temperature changes to navigate their environments. Temperature changes alter where and when mosquitoes seek hosts, leading to changes in disease transmission.

How climate change affects the chemical signals animals use to communicate with each other or harm rivals may be particularly complex because chemical compounds are so sensitive to temperature.

Previously reliable sources of information, such as seasonal changes in daylight, may lose their usefulness when disconnected. This can result in the breakdown of the relationship between day length and plant flowering and fruiting, and the disruption of animal behaviors such as hibernation and migration when day length no longer predicts resource availability.

Changing the brain and cognition

An increase in temperature can disrupt the development and functioning of animals’ brains, potentially affecting their ability to adapt effectively to a new environment. Researchers have documented how extreme temperatures can alter individual neurons at the genetic and structural level, as well as how the brain is organized overall.

In the marine environment, researchers have found that climate-induced changes in water chemistry, such as ocean acidification, can affect the animals’ overall cognitive performance and sensory abilities, such as scent tracking in reef fish and sharks.

behavioral disorders

Animals can respond to adverse climate change by changing their location, from changing the microenvironment they use to changing their geographic range. The event may also shift to different times of day or new seasons. These behavioral responses can have serious consequences on the environmental stimuli to which animals are exposed.

For example, fish in warm seas moved to cooler, deeper waters with much different light intensities and color ranges than what their visual systems were used to. At most, because not all species change their behavior in the same way, species that move to a new habitat, time of day, or season will encounter new ones, including food plants and carnivores, competitors and predators, and pathogens. Behavioral changes caused by climate change are restructuring ecosystems worldwide with complex and unpredictable consequences.

Plasticity and evolution

Animal brains are extremely flexible and designed to suit individual environmental experiences. They can change significantly even in adulthood.

But studies comparing species have revealed strong environmental influences on brain evolution. The nervous system of animals evolves to suit the sensory environment of each species’ domain. These models suggest that new climate regimes will eventually shape nervous systems and force them to evolve.

When genetics strongly influence brain development, nervous systems that are well adapted to the local environment may lose their adaptive advantage as the climate changes. This could pave the way for new adaptive solutions. As the range and value of sensory stimuli and seasonal cues change, natural selection will favor those with new sensory or cognitive abilities.

While some parts of the nervous system are constrained by genetic adaptations, others are more flexible and sensitive to environmental conditions. A better understanding of how animals’ nervous systems adapt to rapidly changing environments will help predict how climate change will affect all species.