How does climate change affect animal brains and behavior?

Climate change is shaping environments at an accelerating rate. Many animal species are facing altered ecosystems as a result of rising temperatures, fast variations in seasonality and ocean acidification. How does climate change affect animal brains and behavior?

Changes in sensory surroundings

Sean O'Donnell, a professor at Drexel University, told The Conversation that changing temperatures shift the energy balance of ecosystems – from plants that produce energy from sunlight to the animals that consume plants and other animals – subsequently altering the sensory worlds that animals experience. It is likely that climate change will challenge all of their senses, from sight and taste to smell and touch.

According to a journal published by the British Ecological Society, researchers examined experimentally the effects of global warming on the efficacy of chemical signals of a mountain lizard. Results showed that the efficacy of scent marks is lower at high temperatures. Moreover, they showed that scent-marked substrates maintained under high temperatures were not selected by females. Their study suggests that climate warming could lead to negative changes in the efficacy of sexual signals, with potential consequences for the sexual selection and conservation of threatened lizard species.

Cognitive and brain changes

Sean O'Donnell told The Conversation that elevated temperatures could potentially cause disturbances to the growth and operation of animal brains, which could have an adverse impact on their capacity to successfully adjust to novel surroundings.

Joshua J. Amiel and his team of researchers from the University of Sydney conducted research about the effects of incubation temperature on the development of the cortical forebrain in a lizard. They found egg-laying animals expose their embryos to a range of temperature regimes, which can affect the hatchling's morphology and performance, as well as its cognitive function. Their research showed that global climate changes, wrought by anthropogenic activities, may directly modify brain structure in reptiles.

According to a journal published on Global Change Biology, researchers indicated that future CO2 levels impair the odor tracking behavior of the smooth dogfish (Mustelus canis). Also, shark feeding could be affected by changes in seawater chemistry, projected for the end of this century.

Disruptions in behavior

Pamela González-del-Pliego and other researchers from the University of Sheffield measured thermal sensitivity (critical thermal maximum – CTmax) of 14 species of Pristimantis frogs inhabiting young and old secondary in the Colombian Andes. 

They indicated that the effects of land use and climate change will continue to pose significant difficulties for the survival of tropical species. Indeed, indirect effects could increase species' vulnerability to climate change and cause population declines before temperatures in the microhabitats exceed their critical thermal maximum.

Shane K. Maloney from the University of the Witwatersrand Medical School and other researchers conducted a survey about the nychthemeral activity patterns of a population of female black wildebeest inhabiting a shadeless environment. They found the wildebeest fed mostly at night, with the proportion of feeding at night increasing when ambient conditions were hotter. Inactive periods were spent mostly lying during cooler weather but standing as days became hotter. These behavioral responses can have major implications for the environmental stimuli animals will be exposed to.