Reptile & Amphibian Forums

hello, i live in Colorado about 30 miles south of Denver in Castle Rock. i was wondering if i could get some good photos of the western rattlesnake. young and baby pics would be especially helpful. i live with my brother and his family on property that backs up to Castlewood Canyon State park so there are a lot of snakes. i also have a 4 year old niece who loves to play in the back yard. we just want to make sure that we can identify all snakes correctly and especially the young ones since we were told that they tend to look simmilar. thanks for any help.

-TJ

Usually young viridis are a lighter color than adults but this specie of rattlesnake is quite variable, This pic is of an adult that we rescued from some hunters.
Link

The (sub)species you have there in Colorado are prairies (viridis) and midget fadeds (concolor). Where you are at, just SE of Denver, they would be prairies. Prairies are quite variable and I am not sure what ones around the Denver area look like but here are some baby prairie shots and there are also several adult prairie shots on my website. They can be quite variable but the thing to look for is the button at the end of the rattle on baby rattlesnakes that would help differentiate it from a hognose or gopher per se.

I don't think you are in the range but the desert massasauga (Sistrurus catenatus) is also in that area and is also venomous. They look quite a bit like prairie rattlesnakes but have a small rattle.

Crotalus viridis photo gallery

According to "Reptiles of the Northwest" Crotalus viridis is the Western rattlesnake. The Prairie rattlesnake is Crotalus viridis viridis. The prairie would be the one you would have in your neck of the woods.

Crotalus viridis has been split up with at least two species or with every subspecies elevated to species depending on your taxonomy.

In brief, Crotalus viridis viridis and Crotalus viridis nuntius are grouped together (and lumped) into Crotalus viridis - the prairie rattlesnake.

All the other Crotalus viridis subspecies are listed now under the species oreganus. This group would probably be the more fitting "western rattlesnake" or "Pacific rattlesnake" - but heck, let's not get into that pesky common name debate. So you have Crotalus oreganus oreganus, C. o. helleri, C. o. caliginis (usually lumped into helleri), C. o. cerberus (recognized by some as distinct species), C. o. abyssus, C. o. concolor, and C. o. lutosus as the subspecies of Crotalus oreganus.

Some authors like Douglas et al. suggest elevating all subspecies to full species. Anyway it doesn't really matter in regards to your question. What is present in eastern Colorado is commonly called the prairie rattlesnake (Crotalus viridis or Crotalus v. viridis, however you want to classify it). The photo in the link HofR posted looks like a northern Pacific rattlesnake (Crotalus oreganus oreganus or C. viridis oreganus).

Here are some articles on all the taxonomy stuff:

Pook, C.E., W. Wüster & R.S. Thorpe. 2000. Historical biogeography of the western rattlesnake (Serpentes: Viperidae: Crotalus viridis), inferred from mitochondrial DNA sequence information. Molecular Phylogenetics and Evolution, 15: 269-282.

Ashton, K.G. & A. de Queiroz. 2001. Molecular Systematics of the western rattlesnake, Crotalus viridis (Viperidae), with comments on the utility of the D-Loop in phylogenetic studies of snakes. Molecular Phylogenetics and Evolution 21(2): 176-189.

Douglas, M. E., M.R. Douglas, G.W. Schuett, L.W. Porras & A.T. Holycross. 2002. Phylogeography of the western rattlesnake (Crotalus viridis) complex, with emphasis on the Colorado Plateau. Pp. 11-50, in G. W. Schuett, M. Höggren, M. E. Douglas and H. W. Greene, (eds.), Biology of the Vipers. Eagle Mountain Publishing, Eagle Mountain, Utah, U.S.A.

Did you say that you have a website..I'd love to see it

Thank you. It's definitely quite difficult to keep up with all the new changes in taxonomy.

It's a work in progress but my website on rattlesnakes is at:
http://www.corallus.com/rattlesnakes/index.html

The pic is a Northern pacific. I thought the name was just viridis. That post was very informative. Thanks!