The saguaro cactus blooms overnight and its flower is visited the next morning by a Gila woodpecker. As the heat of day rises, harvester ants work go about their work, wary of a mortal enemy in the park.

May sees drought conditions in the park, but the saguaro cactus is completely unaffected. A family of ground squirrels is laying low, but a long-nosed snake has caught their scent.

The heat of a scorched riverbed is too much for some animals, but the rare and venomous Gila monster is still active and hunting for prey. Meanwhile, the untiring hummingbird mother will feed her remaining chick until it finally fledges.

Despite the intense heat, a female hummingbird must adapt her diet and work non-stop to feed the young in her nest. The rattlesnakes are breeding, and the victorious male claims its hard-won mate.