Reptile & Amphibian Forums

Can someone tell me the main physical differences, how to distinguish between nelsons and sinaloans? They look identical to me. Thanks in advance. Drew

It kinda depends on if you want to see a difference, there has been so much crossing of the two that very few sinaloans and nelsons are "pure". If they even are distinct subspecies to begin with, but the best indicator is the number of triads few rings = sinaloan, many rings = nelsons, intermediate number = who knows

There are also some fairly subtle differences in head shape, but I am not sure they acutally are different shapes anyway. Either way they are great snakes!

Best,
Vinny

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“There is a grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that whilst this planet has gone on cycling according to the fixed laws of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.” -C. Darwin, 1859

Natural Selection Reptiles

As Vinny said they have become so interbred that it is difficult to distinguish the two.

Traditionally the red banding on Sinaloans was roughly 3 times the width of the black/white/black band, as opposed to only twice as wide on a Nelsons. Aditionally it has become quite common for Nelsons to have some of the black crossing over the red to touch the next black band. That is pretty much unheard of in Sinaloans.

Look at Vinny’s site, he has some beautiful examples.

Does anyone remember several months back there was a link up here that went to a page that had scale diagrams of the heads of the Nelson & Sins that showed the scale count differences? I meant to save it but didn't. I thought it was one of Bob Applegate's pages but I could not find it on his current site.
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L. annulata
Naturalistic vivarium with BSS

My pages has these, were they the ones you meant?????

Nelsons

Sinaloan

Both pics and table data from Williams 1988.

Best,
Vinny
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“There is a grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that whilst this planet has gone on cycling according to the fixed laws of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.” -C. Darwin, 1859

Natural Selection Reptiles

Thanks Vinni,
Yes those are exactly what I was talking about. You should put a copy in the photo section or some other spot. It is a great reference.
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L. annulata
Naturalistic vivarium with BSS

I've run into Bob Applegate @ shows and had him tell me for all intents & purposes that they're basically the same snake w/ subtle differences. I guess he's talking about the ones offered in the pet trade here and in their natural ranges in Mexico.

reako45