Photos: The Creatures of the Desert Monsoon of the American Southwest

In July, waters from the sky return to this typically arid region. What seemed dead in June's sweltering heat gradually comes back to life. The dun shafts of ocotillo plants burst with green leaves, and agaves bloom. Billions of ants take to the air in nuptial flights to mate, eggs of trillions more insects hatch, and grubs under logs pupate into shimmering beetles. This arthropod feast brings out countless amphibians and reptiles, birds and mammals, and clouds of bats thick enough to block out the starlight.

It also draws humans: entomologists and bug lovers of all stripes and striation,herpers looking for snakes and frogs, birders, bat-watchers and botanists. Tens of thousands of people come here during the monsoon for these activities, according to the Arizona Office of Tourism. Some choose to hike and photograph, some to wrangle rattlesnakes and others to collect scorpions and spiders for private stashes or zoos. Many American zoos and insectariums are populated with descendants of this region. "Like moths to the blacklight, we are drawn here each year," says Jim Melli, an exhibition designer at the San Diego Natural History Museum. "Rain in the desert brings it to life in a beautiful and mysterious way."