Reptile & Amphibian Forums

I have a feeling that this is old news, but here goes:

When I was a kid, many people (not scientists, just people I thought were "in the know" seemed to think that there was a difference between Timber Rattlesnakes and Canebrake Rattlesnakes.

As I got older, the "official" opinion seemed to be that there was no difference between the two; both were Crotalus horridus, a species that happened to have several color variations, hence the confusion.

Now I've heard that Timbers and Canebrakes are, actually and in fact, now considered separate species. Is this true?

Thanks.

If anyone's proposed separating Crotalus horridus into two species, I haven't heard of it.

Also, FWIW, the original sinking of Crotalus horridus atricaudatus was just part of a general movement towards ideological opposition to & misunderstanding of the purpose of the subspecies rank, as far as I can tell...

This is coloquial nomenclature that is applicable to various regions. Crotalus horridus is also called the velvet-tail and banded rattlesnake as well as canebrake in the deep south. ~Bill~
The Louisiana Gulf Coast Herpetological Society

i dunno about that-regardless of what we call them from fla. to texas to new hampshire-yellow rattlers,velvet rattlers,velvet tails,canebrakes,timbers,black rattlers-what you have is a species that has two-maybe three- niches/clades/whatever;north,south,and perhaps west,though this last group seems to have a less clearly defined dilineation from the former two than they do from each other.i don't know too much about the western populations(and have precious little first hand experience with the southerns as well)-but i sure can see plenty justification for at least separating the southern from the northern/montanes(i.e. timbers and canebrakes seperate subsp. again)....
more often than not,i am moreso a 'lumper' than a 'splitter'-but i mean really,one has to wonder how can these be considered less different from each other than,say, such 'valid' subspecies as your triangulum,getula,or what about the black racer,in which the northern and southerns can only be differentiated from each other if they are males(difference in just the hemipenes)?...this being the taxonomic 'order of the day',then i just don't see how they should be considered one and the same.not talking about appearences,but just totally different habits/niches/ecosystems they occur in.
that being said i remember beign told that,i believe thru mitochondrial dna testing,the timbers in south jersey-the pine barrens-were,genetically speaking,most closely related to those along the gulf coast area,i beleive louisiana-very surprising...i don't claim to be an expert on these amazing,facinating snakes,but man i find them to be one of the most intruiging species in our country.
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"with head raised regally,and gazing at me with lidless eyes,he seemed to question with flicks of his long forked tongue my right to trespass on his territory" Carl Kauffeld

Crotalus horridus was first identified by Linnaeus in 1758. Pisani et al, 1972 conducted multivariate anaylsis of variation in Ch and came to the conclusion that characteristics tended to be clinal and recommended against recognition of the two subspecies. Brown and Ernst (1986) Brimleyana 12:57-74 countered that morphology in the eastern part of the range supported recognition of costal plains and montane subspecies. Reviewed by Collins and Knight in 1980.
[This information was gleaned from "Scientific ans Standard English Names of Amphibians & Reptiles of North America North of Mexico" Committee on Standard English and Scietific Names, SSAR, chaired by Brian L. Crother] ~Bill~

right,no debating those facts....btw in my previous post i did get a couple facts wrong,the mtdna was concerning canebrakes from fla. compared to a northerly state which escapes me at the moment;and the south jersey ones were most closely related to the north jersey montane ones.....but my point in general was that if you're gonna sink atricaudatus into h. horridus,then how the hell can you justify all those other n.a. snake subsp.?....you can't,obviously.snake taxonomy is very inconsistent the way it stands currently.
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"with head raised regally,and gazing at me with lidless eyes,he seemed to question with flicks of his long forked tongue my right to trespass on his territory" Carl Kauffeld

That would be a good question for Dr. Brian Crother who's field is the DNA of subspecies aned is at SELU in Hammond LA. His email is bcrother@selu.edu. ~Bill~

Hi folks,

...you can't,obviously.snake taxonomy is very inconsistent the way it stands currently.

Well, I guess the problem in taxonomy is the use of different species concepts and the acceptance/denial of the subspecies rank in general.
Some of the (sub-)species were described long time ago, based on morphological characters only but, today DNA analysis is a more and more common procedure, sometimes able to distinguish even morphologically invariant specimens/populations via DNA properties. On the other hand not all (sub-)species have been examined using DNA analysis, so there still are plenty of "old fashioned descriptions" out there. Some will be proven valid, other will be sunk into synonymy.
There also might be distinction and differentation on the base of the venom of snakes, as already shown by Bryan Fry and WW.

Cheers,
Wulf
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http://www.herpers-digest.com - herp related eBooks search -

as far as i know,in north american snakes most of the taxonomy regarding subspecies has not actually been determined thru the use of mtDNA.....so yeah i would think big changes are gonna come,i've mentioned before (as have others) that the genus lampropeltis,to name one,is gonna really be shaken up/broadly restructured-thanks to recent mitochondrial dna testing....
surely that isolated population of horridus(i believe it's in georgia,with neurotoxic qualities to their venom) with the extremely virulent/stronger toxins is unique and very interesting;but is that really something that justifies specific or even subspecific status?and if so,why?to me it seems like a recent,localized and isolated adaptation-i.e. an anomoly-but i admit i want and need to learn more about it....surely there are more long-standing/established and widespread/far-reaching adaptations within the species that are apparently still not enough to warrant splitting the species....would love to hear some others' input to the topic-the timber rattlesnake and it's taxonomic status,etc.-because i would love to know more,they are such an intruiging and fascinating species....maybe from someone who has more 'academic credentials' than me..the only 'studies' i've been involved with is when i head out to observe/count/photograph them between the months of april and november,and that's more for my own personal enjoyment than for any research organization/institue.but i figure that counts too,right?lol.
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"with head raised regally,and gazing at me with lidless eyes,he seemed to question with flicks of his long forked tongue my right to trespass on his territory" Carl Kauffeld

The results of a rangewide genetics study (mtDNA)on Crotalus horridus were reported by Clark et al. (2003). 1) The genetic differences were slight and do not warrant subspecific classification for any segment of the population. 2) The genetic breakdown is at complete odds with the morphological breakdown. Based on morphology (larger size and distinctive color pattern the southern portion of the population was formerly recognized as a subspecies, Crotalus horridus atricaudatus, the Canebrake Rattlesnake. In contrast the DNA study showed two major lineages: 1) an eastern lineage from northeast Florida northward up the Atlantic Coastal Plain and eastern edge of the Appalachians to New Jersey and New England; and 2) a western lineage from the Gulf States northward through the Appalahians and the western parts of the range to Oklahoma and north to Minnesota and Wisconsin.
How do we account for this situation? Twenty thousand years ago giant glaciers advanced across the northern part of North America. Reptiles, including Crotalus horridus died out from the northern parts of their range. Crotalus horridus survived on the southeast Atlantic Coastal Plain and adjacent continental shelf (remember that sea levels were several hundred feet lower than today) and in the lower Mississippi region with isolated populations probably suriving as far north as the karst region of northern Alabama where they managed the severe winters by overwintering in the numerousl caves and sinkholes of the region.
When the glaciers retreated these surviving populations advanced northward. They adapted to the local climates and food sources. Today there are at least five ecotypes or geographic variants, each having its own set of color morphs. These are: 1) southern (canebrake), 2) western, 3)midwestern, 4) Appalachian/eastern, 5) New Jersey Pine Barrens. None of these variants has evolved sufficiently to be considered a subspecies. (Also bear in mind that some consist of more than one lineage.) In conclusion, there are certainly geographic variants within Crotalus horridus and there is nothing wrong with referring to the southern variant as a Canebrake Rattlesnake. But they are not subspecies.
I personally believe that we need two parallel systems of classification. 1)one for the taxonomists and biogeographers, based on genetics and 2) another for the field guides based on morphology (size and color pattern). Look at the ratsnakes (the former Elaphe obsoleta group), for example. The current genetic breakdown, whether right or wrong (and it may well be correct), just doesn't work for a field guide.

The situation in Crotalus horridus does seem to be quite parallel to that in Pantherophis obsoletus if they form eastern vs. western clades... the gist would seem to be that local differences in selective pressures outweigh lineal history in determining patterns of variation in observable characters. Rather than just a confounding factor in creating good nomenclature, this is a very interesting pattern in its own right. Convergent evolution is usually discussed in terms of distantly related taxa, but here there seems to be convergent or parallel evolution between different lineages within a species.

I find this to be an interesting example of taxonomic division.I'll try to keep it short as many of you know you need an extra lung and a ph D to get in depth.I have land in KY and TX and have experienced both horridus TYPES.My opinion is that they are morphologicly diff. but genetic. same.They have many diff.that make them unique.I hope classification and breakdowns take these into consideration.

In Virginia they're technically considered the same species, just two different "populations". The canebrakes are protected because.......in my assumption, their range exists in such a small part of the state. So, for instance if you did a population survey, Timbers come back at.....4700 or whatever, and canes come back at 23. Certainly cause for a freak out session. This is just my speculation. I could be way wrong though, I was wrong one other time....
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Tom

"The more people I meet, the more I like my snakes"