Animals in hot and humid climates develop some certain features which help them to avoid the hottest part of the day or season. Animals evolve to acquire these features and habits to adapt to their environment.
To keep cool, animals have created mechanisms to encourage air circulation around their bodies and to dissipate heat. As for example Camels have a thin layer of fur underneath their bellies to help lose heat, while a thicker layer across their humps shade them. Polar bears keep on swimming to keep them cool.