The upper temperature thresholds of life.

Temperature affects many life processes, but its effect might be expected to differ among eukaryotic organisms inhabiting similar environments. We reviewed literature on temperature thresholds of humans, livestock, poultry, agricultural crops, and sparse examples of fisheries. We found that preferable and harmful temperatures are similar for humans, cattle, pigs, poultry, fish, and agricultural crops. Preferable temperatures range from 17°C to 24°C. Stress temperature thresholds are lower when humidity is higher. However, extended exposure to temperatures above 25°C with high humidity can cause heat stress in many organisms. Short exposures to temperatures above 35°C with high humidity, or above 40°C with low humidity, can be lethal. Increases in exposure, frequency, and duration of stressful and lethal temperatures increase the physiological stress and bodily damage suffered by humans, livestock, poultry, fish, and agricultural crops.