- The Southwestern Black-headed Snake (Tantilla Hobartsmithi), also commonly known as Smith's black-headed snake, is a harmless, tiny colubrid snake native to southern Arizona - While it produces a mild venom specialized for subduing small invertebrates, it lacks a dangerous delivery system and is completely non-hazardous to humans or pets - Because they spend the vast majority of their lives hidden beneath the soil, rocks, and plant debris, encountering one on the surface is a rare treat for local wildlife watchers - Extremely small and slender, usually averaging 8 inches and maxing out around 12 to 15 inches in length