Critically, we found that immune performance in young individuals is more sensitive to high temperatures compared to other age groups. Coupled with evidence of rising temperatures in the region, our results offer insight into how climate change will affect the immune system of wild mammals.

Long-term research is also necessary to identify and quantify the effects of heat-compromised immune performance on individual fitness outcomes, as this could be a mechanism by which climate could increase extinction risk in diverse taxa. As temperatures continue to increase at faster rates, we expect species will continue to experience more diverse and severe physiological effects due to our changing—and increasingly challenging—climate.