Most Arizona residents have encountered the desert tarantula or Aphonpelma chalcodes, one of the most common spider species in the state. It's especially abundant in the Tucson area. Each summer, with the start of monsoon season in June, thousands of male tarantulas leave their burrows and venture out looking for females. The mating season lasts through October.
Desert tarantulas are quite large, brown, and hairy. Males are typically smaller and darker, while females are covered in tan hair that gave them the name: the Arizona Blond Tarantula. Hair helps spiders sense their prey or if a predator is near. Tarantulas prefer dry and well-drained open spaces. So the best area to look for them in Arizona is the Sonoran Desert lying in the southern third of the state. Casa Grande Ruins National Monument, south-east of Phoenix, or Organ Pipe Cactus National Monument, an International Biosphere Reserve on the border with Mexico, are some of the best locations to spot tarantulas. These spiders are most active right before sunset and during the night time.