Red band between two Yellow Bands - Poisonous Coral snake, usually with Black nose
Posted on 07/28/2014 11:46:06 PM PDT by nickcarraway
A new study by a UNC-Chapel Hill biology professor and a graduate student has raised questions about the nature of evolution and whether North Carolina's rarest venomous snake is now almost gone.
The study by David Pfennig, who specializes in evolution, and student Chris Akcali appears in the June edition of the online journal Biology Letters. Among other things, it asserts that the eastern coral snake is now either extinct or "functionally extinct" in the Sandhills region of the state, where many science books have long shown the snake to live.
This was the farthest north that heat-loving eastern coral snakes had been found. Like many species they were uncommon at the edge of their range.
But that's not the main point of the study. It actually focuses on a different serpent, the nonvenomous scarlet kingsnake, which has long been thought by many scientists to mimic the coral snake, taking advantage of similarities to persuade predators that it's dangerous, too.
Both feature bands of red, yellow and black, but in different order, leading to various versions of the rhyme "red on yellow, kill a fellow; red on black, friend of Jack's."
An earlier study that Pfennig performed with another student, William Harcombe, found that predators in areas without coral snakes were significantly more likely to attack decoys made of modeling clay in the proper ring pattern for scarlet kingsnakes.
That study required them to make more than 1,000 soft clay snakes, place them in areas with and without coral snakes, and meticulously tally the beak, claw and fang marks the decoys received from attackers. Predators of the snakes include bears, foxes, raccoons and various birds of prey.
In the new study, the researchers decided to test the evolutionary theory that if an animal was copying another that had vanished that the mimic would no longer continue to improve its disguise, because there would be no apparent benefit.
In falling short of proving it, they may have captured something interesting: a snapshot of a short period in which evolution was just coasting along.
The coral outlier
The coral snake is the biggest outlier in North Carolina's array of venomous serpents. It's a relative of the cobra and carries a particularly toxic venom that attacks the nervous system. It's slender, cylindrical and clad in bright colors.
The other venomous snakes in the state - the copperhead, water moccasin and a handful of rattlers - are all pit vipers, with a venom that attacks the blood and cardiovascular system. They generally have heavy bodies, arrowhead-shaped heads and favor earth tones.
The eastern coral snake is extraordinarily shy, living nearly its entire life out of sight in rodent burrows or under leaf litter or other cover. Its range is believed to include an arc across North Carolina's Sandhills and southeastern coastal plains.
But that doesn't seem to be true any longer, given that no one has positively identified a coral snake in the Sandhills since 1960.
Either it's extinct there or, for any practical purposes such as the effect on kingsnake coloration, it is so rare that it might as well be gone, Pfennig said.
For the study, Akcali located more than two dozen specimens of scarlet kingsnakes that had been collected since 1960. He chased these down in various museums, including the Smithsonian in Washington, and carefully made digital images of them.
The researchers measured the width of the various bands and found that even after the apparent extinction of the eastern coral snake in the Sandhills, scarlet kingsnakes continued to develop wider black bands and shrink their red and yellow ones, coming ever closer to the heavy proportion of black found on the coral snakes.
The shift, Pfenning said, was so clear that it was obvious to the naked eye.
The researchers also deployed more model snakes, retrieving the latest batch a month ago. The results show that predators are still wary of good mimics, Pfennig said.
That, and the evolving of the kingsnakes' bands, are sure to end eventually, Pfennig said. But for now both effects seem to be operating on momentum.
"We believe this is another example of how we can actually observe evolution over a short period, actually over a human's lifetime," he said.
Many questions
The study has created a stir among the state's small circle of snake researchers.
"I don't want to completely dismiss it, but there are a lot of people asking questions about it," said Jeffrey C. Beane, collections manager for herpetology at the N.C. State Museum of Natural Sciences.
Beane said he wondered whether the scarlet kingsnake was actually mimicking the coral snake, whether evolution can occur that quickly and whether coral snakes are truly gone from the Sandhills.
The one place in the state where everyone seems certain that eastern coral snakes still live is in and around Carolina Beach State Park, south of Wilmington. Four were found there last year, Beane said, including one he saw himself. Single specimens have been positively identified in Bladen County in 1984, western Pender County in 1995 and Robeson County in 2009.
Otherwise, there have been few or no confirmed records, he said.
Also, while no coral snake has been found in the Sandhills for more than 50 years, not even as roadkill, it was hard to say for sure that a species as rare and secretive has truly vanished.
"These are all debatable issues," he said.
Michael Dorcas, a professor of biology at Davidson College and author of "A Guide to the Snakes of North Carolina," agreed that it would be hard to say coral snakes were extinct in the Sandhills, but he isn't willing to disagree with it, either.
Snake experts have done a huge amount of field work there in recent decades without seeing any, Dorcas said.
"I've read the paper, and I don't have any problem with the way it's worded," he said. "It's pretty interesting stuff they've found."
I feel bad for the brown water snake. Everyone thinks it is a Water Moccasin. First tip I give someone on Cottonmouths is that for one they swim with their head out of the water. Of course the thicker body and triangle head. They still don’t believe me.
Or DeBLasio and Bloomberg
In Scouts we were taught “red and yellow kill a fellow, red and black won’t hurt Jack”.
In all my years in the woods have never come across either, but then again I look up for deer or hogs, not at the ground where walking.
They don’t want to believe you.
:-\
Photo #2 is a Copperhead.
#1 is a milk snake.
Red and yellow kill a fellow, red on black find of Jack...
friend of Jack
Not a coral snake.
I was wondering the same thing.
Do the predators have prey meetings on occasion, where they warn each other about various coloration patterns to avoid?
I can see harmful stinging insects and the like being mimicked but a deadly snake? It seems to me if a hapless predator tries to eat deadly prey, the predator will die, and this won’t be able to learn from his mistake. And thus won’t be around to avoid any mimics.
I must have dyslexia or something but I still can’t tell the difference.
I get it now. I can’t see photo #1, so i didn’t have context. Thanks.
The unescapable, implied premise is that animals share information, and even do so historically, e.g. “35 generations ago your great uncle Bob tried to eat a black, yellow, and red banded snake and it killed him. So stay away from those things.”
Since the coral snake is so very reclusive, I wonder if there is any documentation at all that predators avoid eating them. Frankly, it smells to me like another evolution pipe dream, where a biologist sees an oddity (like two very similar snakes) and instantly ascribes evolutionary meaning to it.
Scientists consistently state that life evolves to fit a purpose, but they have never identified anything that would guide that evolution to an end result. Although random mutation could explain the filling of empty and more promising niche habitats, it is also logically true that evolution isn't so much survival of the fittest, but rather survival of the fit enough, e.g. maybe giraffes just got taller because they have a genetic abnormality and they managed to deal with it well enough to survive.
Red band between two Yellow Bands - Poisonous Coral snake, usually with Black nose
No thanks, have plenty of those too.
I’m so sorry to hear about her encounter with the copperhead and hope all is well with her now.
Had to get the anti-venom shot. $25,000 for one shot at Duke University Hospital.
I didn't believe my neighbor when she said they have found copperheads on their patio and in their garage.
I thought she was probably misidentifying what she saw until I found a little one on the curb by my mailbox one night.
A friend of mine says he finds them in his yard every now and then, too.
So, now I usually have a short prayer before walking my dogs at night asking God to protect us and keep our path free and safe from serpents. The two legged kind, of course, but mostly the poisonous little copperheads.
While a larger copperhead might give you a dry strike, my understanding is that those little copperheads, not having learned control, bite you with all they have.
I have salt-and-pepper king snakes. They’ll kill and eat copperheads.
Copperheads tend to freeze rather than flee. As such they blend in and are often stepped on, at which their response is to bite.
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