Rattlesnake or Bullsnake? Look at the Tail, Not the Noise

The gopher snake — called a bullsnake across the plains — puts on the most convincing rattlesnake impression in North America. Threatened, it flattens its head into a triangle, hisses through a specialised windpipe flap in a loud rasping roar, coils, and buzzes its tail rapidly against dry grass.

It works. Gopher snakes are killed as rattlesnakes constantly.

Look at the tail

This is the whole answer.

A rattlesnake has a rattle: a series of loose keratin segments at the very tip of the tail, forming a blunt button-like structure that is visibly thicker than the tail ahead of it.

A gopher snake's tail tapers to a fine point, however furiously it is being vibrated.

The sound is not the test. The tail is the test. Ratsnakes, milk snakes, racers, corn snakes and gopher snakes all vibrate their tails in dry leaves, and in leaf litter the result is genuinely hard to distinguish from a rattle by ear.

One caveat worth knowing: a rattlesnake can lose its rattle to injury, and newborn rattlesnakes have only a single button that makes no sound. So a rattle proves rattlesnake, but the absence of one is slightly weaker evidence. Combine it with the next test.

Look at the head-to-neck transition

Rattlesnakes have a genuinely broad, blocky head that meets the neck at an abrupt step. The neck is dramatically narrower — the outline looks like an arrowhead on a stick.

Gopher snakes flatten the head when alarmed, but the underlying skull is narrow. Even flattened, the head is only slightly wider than the neck, and the transition is a gradual taper rather than a step.

Look also at the snout: gopher snakes have a pointed nose with a single enlarged scale at the tip, adapted for pushing through soil. Rattlesnake snouts are blunt and rounded.

Listen to the character of the sound

If the animal is out of sight, the sound itself carries information.

• A rattlesnake's rattle is a dry, high, continuous buzz, fairly steady in pitch — closer to a cicada or an electric razor.
• A gopher snake's hiss is lower, longer, and rasping, delivered in extended bursts with pauses to breathe. It sounds much more like an animal than a machine.

Quick reference

The pattern difference

Gopher snakes have squarish dark blotches on a cream, tan or yellowish ground — well separated, with clean edges, and becoming crossbands towards the tail.

Western diamondbacks have diamonds with fuzzy, indistinct borders. Prairie and western rattlesnakes have rounded oval blotches with pale edges.

The gopher snake's markings tend to look crisper and more geometric, and the ground colour is usually paler.

Why it is worth getting right

Gopher snakes and bullsnakes are among the most useful animals on a western property. A single adult eats a great many gophers, ground squirrels and rats each year, and they use the same burrow systems rattlesnakes do — meaning a resident bullsnake is competition for the animal you actually want to avoid.

Killing one to be on the safe side is precisely backwards.

And as always: the safe response to a coiled, buzzing snake of uncertain identity is the same either way. Step back, give it a wide berth, and let it leave. It will.