Coral Snake or Kingsnake? The Rhyme Works — With Two Caveats

Almost every reported coral snake is a scarlet kingsnake. The mimicry is genuinely good, which is the point of it — harmless snakes that resemble a dangerous one get left alone more often.

Two checks separate them, and one of them is easier than the famous rhyme.

The easier check: look at the snout

US coral snakes have a solid black snout, black from the tip back to just behind the eyes.

Scarlet kingsnakes, milk snakes and scarlet snakes have red or pale snouts.

This is a single feature, it is at the front of the animal where you are most likely to have a clear view, and it does not require you to work out which colour is adjacent to which. If the nose is black, take it seriously.

The rhyme, and where it fails

Red touches yellow, kills a fellow. Red touches black, friend of Jack.

On a coral snake, each red ring is bordered on both sides by narrow yellow rings. Red and yellow are adjacent.

On a scarlet kingsnake or milk snake, each red band is bordered by black. Red and yellow never touch.

The rhyme is accurate for all three coral snake species in the United States. It has two important limits:

It does not work outside the United States. Several Central and South American coral snakes have red bands bordered by black, and there are coral snakes with no red at all. Applying the rhyme in Mexico or further south can produce a confident and completely wrong answer.

It fails on abnormal individuals. Occasional aberrant coral snakes have irregular banding. It is a strong rule, not a law.

The third check: do the rings go all the way round?

Coral snake rings encircle the body completely, including the belly. Turn a shed skin over and the bands continue.

Milk snakes have saddles, not rings. The red-brown blotches sit on the back and stop at the sides, and the belly is a black-and-white chequerboard.

Scarlet snakes have a plain white belly with the red blotches stopping well short of it.

Note that you should be examining a photograph or a shed skin for this, not a live snake.

Quick reference

Notice what is missing from that table: head shape and pupil shape. Coral snakes have narrow heads and round pupils, exactly like the harmless mimics. The usual venomous-snake tests are worse than useless here.

Why coral snake bites are unusual

Coral snakes are small, secretive and largely fossorial — they spend most of their time under leaf litter, logs and boards. They do not strike from a coil the way a pit viper does; their fangs are short and fixed, and envenomation usually requires a sustained chewing grip.

The consequence is that nearly every coral snake bite happens to someone who picked the snake up. Frequently to check the colour bands.

That is worth sitting with. The rhyme is a good rule, and the correct way to use it is to decide how alarmed to be about a snake you are already leaving alone — not to decide whether to handle it.

If you are bitten

Coral snake venom is neurotoxic and its effects can be delayed by several hours before progressing rapidly to muscle weakness and difficulty breathing. There may be very little pain or swelling at the bite site early on, which makes the injury seem trivial when it is not.

Call emergency services immediately, tell them you suspect a coral snake, keep still, and go to hospital regardless of how minor it appears. Do not wait for symptoms.