In the desert, when temperatures are high, rattlesnakes become more active at night. Rattlesnakes have no control system for their body temperature and cannot handle excessive heat, so they remain underground during the day hidden in burrows, under rocks or in the shade of shrubs. In the Spring and Autumn, when daytime temperatures are milder than summer months,Rattlesnakes are seen sunbathing (THEY DON'T USE SUN TAN LOTION) on rocks or hunting for food during daylight ours
Rattlesnakes have triangular-shaped heads, which are broader than their neck. Their trade-mark is a rattle on the end of their tail, which serves as a warning signal when they feel threatened. Rattlesnakes do not rattle their tail when hunting, and they do not always rattle their tail when taken by surprise. So don't depend on the warning rattle to alert you that a Rattlesnake is nearby.