The sonoran mountain kingsnake, like several species of milksnake, uses mimicry to defend itself. It is colored in a similar pattern as the Sonoran Coral Snake which posseses neurotoxic venom that attacks the nervous system. This is why predators stay away from the kingsnake, just in case. But unlike the coral snake, the sonoran mountain kingsnake is non-venomous, and is actually quite gentle along with most other kingsnakes. For this reason, it is also a pet species of snake.
Like most snakes, the sonoran mountain kingsnake feeds on basicaly anything it can swallow whole. It most likely feeds on desert shrews, cliff chipmunks, rock squirrels, harris' antelope squirrels, round-tailed ground squirrels, deer mice, cactus mice, white-throated woodrats, gambel's quail, scaled quail, common ravens, cactus wrens, curve-billed thrashers, black-throated sparrows, western rattlesnakes, Arizona ridge-nosed rattlesnakes(Arizona's state reptile), western diamond-back rattlesnakes, and black-tailed rattlesnakes.
The sonoran mountain kingsnake has black, white, and red bands running down it's body, it uses these as a form of mimicry as shown in the MIMICRY paragraph. It is non-aggressive as also said above.