Bob Mason's thoughts on my 3-stripe polymorphic concinnus

[ConcinusMan]

I wrote to Robert T. Mason of Mason Labs about the curiosity of my "dimporphic" (as I call them) T.s. concinnus, which produce both 3-stripe and regular single-stripe T.s. concinnus.

This is what I said:

I am revisiting an old curiosity which I looked into back in the early '90's. In Clark Co. Washington and even areas along the Willamette and Columbia river junction in Oregon I can find 3 stripe T.s. concinnus. Especially in the Salmon Creek, WA watershed I can find both types, the triple stripe version being less common. I've even produced litters from both types that were caught in the same population. There has in the past been doubt on my part that they are "pure" but there's no other sirtalis' anywhere near where I find them. Also, single stripe parents from that population still produce some 3 stripe babies and they do retain their lateral stripes into adulthood. Same goes for 3 stripe parents; the offspring are of both types. So, I came to the conclusion that this is just polymorphism, or more appropriately dimorphism.

Now I have people doubting me when I tell them that they are pure T.s. concinnus and that no crossing of subspecies has been done on my part and it's highly doubtful any crossing occurred in the wild.
Has any research been done on this particular subject? Any theories or thoughts you might have on why this seems to happen in this particular area would be welcome.


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Robert T. Mason, Professor of Zoology wrote back and said:

I don’t know of anyone who is studying this but it is certainly something that PNW herpetologists have been aware of for well over a century. My own opinion is that you are exactly right. This seems to be just a polymorphic trait that is interesting as to when and how it occurs, but one does not have to invoke crosses with other species to explain it. A comparable phenomenon is the extensive variation in color patterns in our local T. ordinoides.

It’s nice to hear that you have been breeding T.s.c.’s. That would probably constitute you as the local expert.

Best regards,

Bob Mason

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Honestly, I don't think it's as complicated as the polymorphism seen in northwesterns. It's just a simple gene that gets turned on of or off like a switch, I suppose. Some babies have it turned "on" others "off" but they all (snakes from the area where 3-stripes occur) carry it, and can pass it on. Being how it's not as common as the normal single stripe variety, it may even eventually prove to be recessive but that's just speculation at this point. All I know is, my 3 stripers are concinnus, just a little different, and still very attractive and desireable snakes to have around. Other than the extra stripes, they are every bit what I would expect from a concinnus as far as behavior and disposition goes.

They're just "special" is all.

I love them.