Hybridization in cottonmouth snakes occasionally occurs naturally in the wild. No one really knows for sure why hybridization takes place in the animal kingdom, but there are a few educated guesses that proclaim if closely related species of reptiles like the cottonmouth snake and the copperhead are unable to locate a suitable mate of the same species but are able to locate a suitable mate of a closely related species hybridization can occur. Chances are breeding between the two occurs fairly frequently, but hybrid offspring being produced as a result of these breedings is a fairly rare occurrence.
Cottonmouth snakes have been known to interbreed with copperheads that overlap in there same territory. Also, there have been successful captive breeding projects that resulted these hybrid cottomouth /copperheads crosses being produced. The common name for these hybrid animals is nothing simpler than the “cottonhead.”
Male Cottonhead hybrid ~This image and animal is owned by Bart Borchert~
The animal pictured above is a male cottonhead hybrid owned by Bart Borchert of Sandhill Reptiles he was produced back in 2003 by Mardi Snipes and this animal is part of the original captive breeding program for the cottonmouth / copperhead hybrid also know as the cottonhead. Looking at the image you can easily see characteristics from both the cottonmouth and copperhead. The animal overall looks to have much of the bulk and head shape of the cottonmouth even the long tail appears to be much more cottonmouth like. Looking at the animal from a copperhead point of view and you see some very obvious characteristics of the copperhead lineage. For example the classic orange autumn colors along with the banded pattern, but those bands do look to be expanded a bit which is a little indicative of the cottonmouth. If you happen to stumble upon this animal in the wild chances are even the experienced reptile enthusiast would probably mistake this animal for a full blooded northern copperhead.
Seeing that the copperhead blood really seems to dominate the overall appearance of the hybrid cross I would imagine that hybridization may occur more often than expect and simply overlooked because the cross in’t so obvious.
A possibly issue with hybrid venomous snakes is how the cross breeding effect the animals venom and how to administer bite treatment for a hybridized animal. With the cottonhead we are pretty fortunate that they both are equipped with hemotoxic venom so bite treatment would still remain along the same lines as receiving a bite by either species without the cross involved.
I’m currently working to acquire a few images of these cottonmouth snake / copperhead snake hybrids as I personally know of two different breeders that are currently working with them in they’re breeding projects. I have seen images myself and most cottonheads appear to resemble copperheads more so than cottonmouths. The cottonhead does appear to be a little stockier and have a more cottonmouth like structured head and tail but the over color looks like a very dark phase copperhead.