Our recent encounters left me curious. Fortunately, research can be done online these days, and not up close and personal.
Our tarantulas would have been males, out looking for females. It's mating season. Many will not survive it. The Sonoran Desert location decrees that they were "Blonde Tarantulas" or Aphonopelma Chalcodes, and the darker coloration furthers decrees that these were males. Females are lighter in color, and tend to stay near their burrows. They also live about twice as long as the males, partly due to less wandering, partly due to making a tasty post-coital snack of their mate.