|
1-10 of 26 messages
|
Page 1 of 3
Next
|
|
Rattleless Crotalus questions
|
Reply
|
|
by CanadianSnakeMan on October 25, 2010
|
Mail this to a friend!
|
I have been hearing more and more about rattlesnakes being found in the wild without rattles. I wanted to know what other members think of this.
1. Are there more than one species of Crotalus that have been found without rattles in the wild?
2. When was this first noticed?
3. Are these snakes actually incapable of growing ratttles after being brought into captivity?
4. Have the findings been concentrated to certain areas or are they widespread?
I am interested in collecting some data about this phenomenon. It would be nice to know whether this is some kind of adaptation to humans constantly killing rattlesnakes or if there are other environmental factors involved that could be causing this.
Thanks!
Luke
|
| |
|
RE: Rattleless Crotalus questions
|
Reply
|
|
by CrotalusAdamanteus on October 25, 2010
|
Mail this to a friend!
|
|
I don't know too much about this, only little bits and pieces that I have read. I know of one population of the southern coast of California (if I'm not mistaken) that lack rattles. There are also at least 3 or 4 others but not sure of the species. There are a few reasons I think they are evolving without their rattle. One because their rattle equals certain death when they buzz up in front of stupid people and maybe because other populations lack large predators so they no longer need or use the rattle? I'm not completely positive and I know someone else can give you a better answer/explanation. Good luck, Neil.
|
| |
|
RE: Rattleless Crotalus questions
|
Reply
|
|
by CanadianSnakeMan on October 25, 2010
|
Mail this to a friend!
|
Thanks Neil.
I am aware of Crotalus catalinensis which has evolved to lose its rattle, but I'm referring to the reports (which it seems like you've also heard of) of snakes that normally have rattles being found without them.
You're right, I think it might have to do with the constant onslaught or human extermination. I'm also wondering if it might be caused by pesticides or industrial pollutants, or perhaps because there are no more herds of hooved animals like the Bison around, which is probably why they evolved rattles to begin with.
It would be interesting to at least confirm that this is in fact happening.
I found a couple of pictures in my 'internet research'!
http://2coolfishing.com/ttmbforum/showthread.php?t=269513
http://www.kingsnake.com/hudspeth/rattless.jpg
|
| |
|
RE: Rattleless Crotalus questions
|
Reply
|
|
by Cro on October 26, 2010
|
Mail this to a friend!
|
While the Santa Catalina Island Rattlesnake is a well known rattleless rattlesnake, it is quite a stretch to assume that rattlesnakes are evolving to have no rattles.
In the two links that were posted, we see one rattlesnake that has had the end of its tail cut off, and we see another rattlesnake that has broken off all of his rattles, which is fairly common.
If the rattlesnakes were indeed evolving to not have rattles, we would be seeing hundreds of photos using a simple Google search.
Most stories out there about rattleless rattlesnakes are due to harmless snakes being called rattlesnakes.
To most of the people out there, any snake they find is venomous, and if it is in a western state, it is automatically called a rattlesnake, if it is found near water, it is called a cottonmouth, and if it is found in the eastern states, it is called a copperhead.
Best Regards
John Z
|
| |
|
RE: Rattleless Crotalus questions
|
Reply
|
|
by CrotalusAdamanteus on October 26, 2010
|
Mail this to a friend!
|
|
Crotalus Catalinensis is the species I was referring to off the coast of Mexico, not California. I'm not sure as to what the other species are. I'm sure that other people here do. Good luck with your answer.
|
| |
|
RE: Rattleless Crotalus questions
|
Reply
|
|
by CanadianSnakeMan on October 26, 2010
|
Mail this to a friend!
|
John,
Thanks for the insight. I never knew that snakes were misidentified in such a way, but it doesn't come as much of a surprise. This could easily explain all the stuff I've been hearing.
Crotalids are a genus that I've always been interested in but have never kept myself. Please excuse my inexperience ;)
The only thing that leads me to question the first picture where the tail is aparrently cut off is that the end of the tail appears to have scales instead of scar tissue. Can anyone explain this?
|
| |
|
RE: Rattleless Crotalus questions
|
Reply
|
|
by MikeB on October 26, 2010
|
Mail this to a friend!
|
Why did most species of rattlesnakes evolve rattles? They are surely of no use -- even counterproductive -- in pray capture. The answer, I suspect, is that in most of their ranges they co-evolved with large herds of hoofed mammals (primcipally the bison) which were likely to step on them. What better way to part an oncoming herd than sound off with that rattle, which to the buffalo says "don't step here or youi may get a nasty bite." This would make sense of the sole non-rattle-equipped rattler is located on an island where herds never lived.
So the evolutionary advantage (a noisy rattle) has become an evolutionary disadvantage (no more herds, but people with guns and sticks who are likely to kill you if they hear you.) A mutation like that would not take a huge amount of time to spread through a population of it conveyed significant survival advantages. The buffalo herds have been gone for about 140 years, and people have flooded into the rattlesnake's range for about as long . . . how many generations is that? If you breed annually, as most snakes do, 140 generations . . . so not surprising that in some localities where the environmental pressures are strongest, more rattle-less mutatons would be breeding more succesfully, even by a tiny margin. It would not be surprising to see most species of rattlesnake lose the rattle completely within another 300-500 years.
|
| |
|
RE: Rattleless Crotalus questions
|
Reply
|
|
by Cro on October 26, 2010
|
Mail this to a friend!
|
Time will surely tell if evolution will change more of the rattlesnake clan to not grow rattles.
We do see new studies that suggest rattlesnakes that do not rattle when approached have a survival advantage over those that do, at least when approached by humans.
Apparently, there is enough survivability of the "quiet" rattlers, that some populations have selected for that to the extent that the majority of the population now behaves that way.
One has to remember though, that snakes around the world, both venomous and non-venomous, often vibrate their tails when they feel threatened. Those snakes did not evolve that tendency to mimic rattlesnakes. If anything, the tail vibration came long before, and was what eventually led to rattles being developed.
Tail vibration could serve many purposes. If the snake is in dry leaves or grass, it might produce sound. But, what if the snake is out in the open ? Then there is no sound created. Perhaps the tail vibration serves as a distraction from the important part of the snake, the head, so that a predator might be drawn to the wrong end of the snake ? A snake can easily lose several inches of tail and still survive. Or, perhaps the tail vibration even sets up waves in the ground surface that are sensed by other snakes near by, who are also warned ?
I guess the point I am trying to make, is be careful about making anthropomorphic guesses about what animal behavioral traits might actually be for. It is easy to make assumptions like rattles evolving to protect snakes from large grazing animals like bison, but, if that were the case, why do we not see rattles on snakes of the African and Australian plains, which also have huge numbers of large grazing animals ? After all, those old world snakes have had much more time to develop something like a rattle, than the modern rattlesnakes have.
Oh, and as far as the photo of the rattlesnake with the tail chopped off, the scales that formed could have easily happened instead of scar tissue, if there were a bit of skin still attached that healed over the wound.
Best Regards
John Z
|
| |
|
RE: Rattleless Crotalus questions
|
Reply
|
|
by agkistrodude on October 26, 2010
|
Mail this to a friend!
|
|
I believe there are also rattlesnakes that have lived for eons in areas where there never were herds of hoofed animals. Just one of natures mysteries that will never be answered, just theorized many times over. Heck, if they never had rattles, what would we call them? Take care, Marty
|
| |
|
RE: Rattleless Crotalus questions
|
Reply
|
|
by CrotalusAdamanteus on October 26, 2010
|
Mail this to a friend!
|
|
There is your question better answered. Everyone did a much better job than I could explaining the subject. As far as most people misidentifying snakes and assuming every snake they see is venomous, this happens all too often.
|
| |
|
Email Subscription
You are not subscribed to this topic.
Subscribe!
My Subscriptions
Subscriptions Help
Check our help page for help using
, or send questions, comments, or suggestions to the
Manager.
|
