In our South African climate heat stroke is a definite possibility when the temperature rises above 25 °C. The chinchilla will look like it’s having a seizure and will have fit like tremors. In summer we keep the temperature of our chinchilla room as close to 25 °C as possible. Again there are lots of suggested remedies like dunking the chinchilla in cold water. We do not agree with this as we believe the sudden change in temperature can cause shock. What have worked for friends of ours is to always have a couple of plastic cold drink bottles filled with water in the freezer. If a chinchilla overheats they put the bottle next to the chinchilla and so far this has always done the trick. We would rather recommend that you keep the temperature low enough in summer.