While many different snake are black and yellow, the most commonly encountered black and yellow snakes are kingsnakes, garter snakes and ribbon snakes. Kingsnakes in the eastern United States display a black base color topped with yellow bands. Garter snakes are highly variable, but most are black, brown or gray with longitudinal yellow markings and ribbon snakes, a close relative of garter snakes, also feature yellow longitudinal stripes.
Kingsnakes, garter snakes and ribbon snakes are harmless species that represent no threat to humans. They actually provide a number of pest-control services for the humans who share their territory. Garter and ribbon snakes consume frogs, worms, minnows and insects. Kingsnakes primarily consume lizards and snakes, but they also eat rodents from time to time. Kingsnakes even hunt and kill venomous snakes, as they are immune to the venom of pit vipers that share their range.
Kingsnakes are the largest of the three species, sometimes reaching 4 feet in length. Garter and ribbon snakes are generally less than 4 feet long. While all three species retreat or hide at the sight of humans, they may engage in defensive displays if they feel cornered. All three species may flatten their heads, making them appear triangular, which often causes people to confuse them with venomous pit vipers. Additionally, kingsnakes may shake their tails, which can cause a sound similar to that produced by a rattlesnake.