A lesson as to why you don't rely on one way to I.D a snake!
Updated: Jul 17
Snake scales and Identification
Features of scale arrangements and position is widely used by workers to distinguish one species from another. This could be scale 'x' is in contact with scale 'y', scale 'x' is divided, scale covers 'x' amount of the body and scale 'x' is adjacent to 'x' body part. This is usually quite reliable allowing a certain degree of confidence to an identification.
The case below we have three snakes - two are the same species while the third is different. The main point of difference used is the presence or absence of a loreal scale. This scale sits in front of the pre-ocular and first supraocular (these scales border the eye) and posterior (behind) the nasal scale (this scale contacts the nostril).
The two snakes on a natural background exhibit typical scalation features for their respective species while the animal on the green grid below appears to lack the loreal scale. The key feature to split a Rough scaled snake Tropidechis carinatus- a dangerously venomous elapid from a harmless Keelback Tropidonophis mairri is the absence of a loreal scale.
The snake on white had been brought in to a vet after being attacked by a cat. Being familiar with the snakes in the area the vet knew what species it was but decided to use this opportunity to show a vet student the difference. I received a text message asking to confirm what it was from a now very nervous vet. I did confirm his original identification was correct and the snake was an aberrant individual. As the snake had died we got the chance to go and get pics of the unusual specimen. In this case the Keelback had an unusual scale mutation which fused the loreal scale to the nasal scale. This condition to the untrained eye, made this snake to appear as if it was a very different species.
The take home message is simply this - get an expert to execute identifications as sometimes snakes don't fit the arbitrary boxes we place them in. It is great for member of the public to try but when there is an emergency it is best left to experienced professionals.
Please share this post widely as it goes to show no matter how much you know on a topic there is always something new to be learnt on the subject.