Red to black venom lack. Red to yellow kill a fellow.

Indigo Expeditions Wildlife Research & Endangered Species Conservation in Guatemala

Red to black venom lack. Red to yellow kill a fellow.

Another species I was very excited to find is the variable coral snake (Micrurus diastema). As its common name suggests its colouration and pattern are highly variable. Due to this fact, I treat any snake with any hint of bands of red / orange, yellow / white, and black as a coral snake until I am sure what it is. Coral snakes are highly venomous and so getting the identification correct is critical.

The diagnostic rhyme “red to black venom lack, red to yellow kill a fellow” is not enough for me to be certain that what I am looking at is safe to handle freely. The ‘Venom Lack’ rhyme originated in the US where it holds true, however as soon as you pass south of the border the picture starts to get rather confusing.

This is well illustrated by the variable coral snake, which in most cases fits the rhyme, red bands touch yellow, however, in some individuals, yellow bands are absent so red touches black, and even other case bands are absent altogether except for a single black band around the neck – again red touches black. In other coral snakes, such as the elegant coral snake (Micrurus elegans), red always touches black.

And that’s just the coral snakes. In the tropical regions of the America’s we also encounter many species of harmless snakes that look like coral snakes, some of which like the false coral snake (Pliocercus elapoides) have banding patterns where red touches yellow. Because of this, there have been several times where I almost convinced myself that what I was looking at was a coral snake, when in fact it was a harmless look-a-like!

Finally, after many false starts, I caught the first coral snake here at Las Guacamayas last week. Its colouration was almost identical in shade and pattern as the milk snake (Lampropeltis abnorma) I had caught the week earlier. The only real difference between them is the order of the bands, the size of the eyes and the scalation (e.g. coral snakes have far fewer rows of dorsal scales than milk snakes).

I will still remain on the cautious side when I see a red/black/yellow snake, even if it is not obviously a coral snake!

Indigo Archives: First Published 1 December 2013


Published : 1st December 2013


Field Notes Archive

You may also like to read…

New caiman pool at La Aurora Zoo

New caiman pool at La Aurora Zoo

New caiman pool at La Aurora Zoo Indigo Expeditions met with Carlos Cozano, head of reptiles, to see the new caiman...

Indigo News