Monday, October 5, 2009

Snake Identification Help

Can someone ID this wild beast so I can label the photos correctly? It was in dry Black Oak savannah just above a wet swale in Gary, Indiana. Thanks. Super skinny - about 15 mm in diameter and close to 1 meter in length..

12 comments:

Scott said...

It kind of looks like a Ribbon Snake (Thamnophis sauritus) to me, but I'm not expert.

Scott said...

I keyed out the snake tonight (not sure that I've ever keyed out a snake before!) and would call this a Northern Ribbon Snake (Thamnophis sauritus ssp. septentrionalis). Like I said before, I'm not an expert on snakes, so if anyone disagrees, I would be interested in figuring out where I went wrong in the key.

Keith said...

Good to know. Thanks Scott!

nina at Nature Remains. said...

Check out the Chicago Garter snake. Geog. is right and they have those vertical black crossbars.
But, I'm no expert, either.

Scott said...

Nina's suggestion is a possibility; a portion of my ID was based on the description as "super skinny - about 15 mm in diameter and close to 1 meter in length." Wouldn't the Chicago Garter Snake (which is said to be a questionable subspecies of the Eastern Garter Snake) have a thicker body?

Kelly said...

Nina is correct about Chicago Garter Snake (Thamnophis sirtalis semifasciatus). The black crossbars on the anterior portion of the animal, plus the dark markings on the upper "lips" make it an easy call on that versus any ribbon snake. That's a neat range-restricted subspecies that I've never seen. Great find!
Cheers

Keith said...

I'm not arguing or skeptical because I know NOTHING about snakes, but wanted to share a few thoughts. The dimensions I provided were estimates but I believe they were very close. The Quercus velutina (Black Oak) leaf petiole that lies across the snake measures out on screen to 1/6 or 1/7 the diameter of the snake at that point. The Black Oak petioles in my yard are 1.2 mm in diameter consistently, but are already brown and dry and I believe they would have been 2 mm when living. If the Miller Woods Black Oak petioles are 2 mm, the diameter of the snake at that point would be close to 14 mm. Are dimensions/ proportions a part of the keys, and could someone share keys and a description of the subspecies? Thanks! Does the typical Garter Snake ever have such extreme length-to-width proportions? Just curious. Thanks very much to each of you for all the great commentsssss:>-<

Scott said...

Thanks for your help, Nina and Kelly. I should stick to plants!

I use Minton's Amphibians and Reptiles of Indiana as my guide. This book includes the Chicago Garter Snake with the Eastern Garter Snake. Using this key, the light lateral stripe on Thamnophis sirtalis should involve only the second and third scale rows or the stripe should be absent, while the light lateral stripe on Thamnophis sauritus (and others) should involve the fourth scale row at least anteriorly. It looks to me like the light stripe goes into the fourth row of scales, but I must be misinterpreting this character. Maybe the stripe is absent, if I'm looking at the wrong thing? This is the first time I've keyed a snake; any help on where I went wrong would be appreciated. Proportions come into play after separating Thamnophis sirtalis from the others (T. proximus, T. sauritus, T. butleri, and T. radix).

Keith said...

I shared the photos and comments with Alan Resetar, renowned herpetologist at the Field Museum in Chicago. With permission, here is his reply: "The snake is definitely a garter snake. The validity of the Chicago garter snake is in question. If one is in the Chicago gartersnake camp, it is definitely diagnostic of that subspecies. However it is safe to call it an eastern garter snake."

Scott said...

Interesting. Sorry I led you the wrong way from the beginning.

Keith said...

Baah! No apology necessary! As Einstein is reported to have said, “Anyone who has never made a mistake has never tried anything new.” By the way, where did you find snake keys?

Scott said...

There are keys to Indiana's amphibians and reptiles in Sherman Minton's Amphibians and Reptiles of Indiana.