Heat Stress

Female Great-tailed Grackle, Quiscalus mexicanus coping with the 41°C day.

The behavior of various animal species changes as the season gets hotter. Birds pant, lift their wings away from their body, find shade, and appear more flush as vessels dilate to release heat. Many mammals also pant, lay flat in a cooler area, and expose the short-haired parts of their body. When the humidity is high, panting increases significantly. The evaporation of water from the lungs is not easily absorbed by the moist air.

The signs of heat stress in other animals are not unlike those of a person. An overheated animal may have heavy panting, glazed eyes, vomiting, unsteadiness, and a rapid pulse. When body temperature rises above 40°C (104°F) then it is considered heat stroke which can be life threatening. The mucus membranes become bright red, heart rate increases, vomiting and diarrhea may occur, and the lethargy and stupor may eventually become seizures and coma. For animals experiencing heat stress or early signs of heat stroke, it is important to use cool, not cold, water and a fan if possible. An animal with a late sign of heat stroke still needs cooling, but with the risk of damage to the liver, kidneys, and heart, a vet should be called.

Those who work with animals that live outside are trained to look for these symptoms, but it is also important for the pet owner to be aware. Always keep in mind that wild animals and many exhibit animals have acclimated to the climate as they have never lived indoors with air conditioning or heat. Prevention is best, providing the animal with adequate shade, water, and electrolytes if necessary. Those animals who haven't had time to acclimate to the heat should not remain outside for long.