Monday, January 31, 2011

Cottonmouth Myths II: Cottonmouth Breeding Balls

There is no such thing as a Cottonmouth breeding ball.

Cottonmouths, Agkistrodon piscivorus, are so feared and misunderstood that perhaps the most terrifying thing the average citizen can imagine is these snakes in the process of making even more Cottonmouths.  I would guess it is a combination of fear, rural folklore, and maybe just the fact that Cottonmouth biology is not often brought up in school, but there is a lot of inaccurate information about how these vipers reproduce.  One tale I have heard from time to time is that of the casual fisherman or boater coming across a giant, swirling, tumultuous mess of snakes: a Cottonmouth breeding ball.

A snake breeding ball occurs when there are many male snakes competing over a single (or a few) female snakes.  Wrestling each other for the first opportunity to mate, a breeding ball can be a spectacular sight.  Although there are a number of snake species that are known to engage in this interesting behavior, Cottonmouths aren’t one of them.

Successfully reproducing is one of (if not the most) important activities an animal can accomplish.  This is, after all, the way an individual is assured that their genes may pass on to the next generation.  What kind of species is not driven to reproduce at every opportunity? The extinct kind.

For females of many species, once they are pregnant they are unable to reproduce again for a relatively long time.  This means that when there is a ready, willing, and able female in the area, many males are likely to have their interest piqued.  And if necessary, these males are going to compete against each other strongly for the first opportunity to mate.

Male watersnakes (of the genus Nerodia, for example) may detect a female ready to breed by picking up on her pheromone trail.  If there are many males in the swamp, they may converge on the female at the same time.  There is a huge incentive for being the first male to breed, not only does the male secure a good chance his sperm will fertilize the female’s eggs, but male watersnakes of some species are known to deposit a plug in a female’s cloaca that temporarily prohibits other males from inserting their hemipenes (a male snake’s reproductive organs).  So, with this in mind, the males writhe all over each other (and the female) attempting to be the first to maneuver into position, resulting in a snake breeding ball.

            There are other ways for males to compete for females in the animal kingdom.  One method is by defending a territory from other males, securing the right to breed with nearby females.  Another technique is to impress a female with elaborate displays.  But for male Cottonmouths, the way they secure breeding rights to a female is one that may be familiar to anyone that has spent a lot of late nights in the local bar.  That is to say, when two male Cottonmouths have their eye on the same female, they will simply fight over her.

Cottonmouth combat is probably similar to that seen among other vipers, such as rattlesnakes, wherein the males engage in a ritual combat, raising the front third of their body in the air and becoming intertwined with each other as they attempt to wrestle each other to the ground.  Eventually, one will be determined as stronger, and the victor will proceed to court the female while the loser flees. 

            Unfortunately, we don’t know much else about the behavior surrounding Cottonmouth courtship.  But, it is likely that the winner of the combat has the best chance of mating with the female.

            So, how did the Cottonmouth breeding ball tale start?  I would venture a guess and say that this aquatic viper has simply been once again struck by a case of mistaken identity.  I don’t think it is a stretch to imagine a breeding ball of watersnakes being misidentified as Cottonmouths in the muddy twilight of an isolated swamp.  Watch your step.


This isn't the first time I've written about Cottonmouths.  For a discussion of Cottonmouths allegedly dropping into boats, click here.

I wrote about how these snakes are quick to show up when a lot of toads (= food) appear here.  I've also written about accompanying Cottonmouth researchers as they wade through swamps to catch snakes in the spring as the reptiles try to take advantage of the new warmth and at night in the summer as the venomous snakes swam around me.  Finally, I provide some tips on recognizing Cottonmouths from non-venomous watersnakes here.

First and third Cottonmouth pictures provided courtesy of Fingerprince Prints.

Much of what I write is based on my experience in the field, however I also rely on the research of others, citations of some relevant scientific articles are below.

Herrington, R.E. (1989). Reproductive biology of the brown water snake, Nerodia taxispilota, in central Georgia. Brimleyana, 15, 103-110

ALDRIDGE, R., BUFALINO, A., & REEVES, A. (2005). Pheromone Communication in the Watersnake, Nerodia sipedon: A Mechanistic Difference Between Semi-aquatic and Terrestrial Species The American Midland Naturalist, 154 (2), 412-422 DOI: 10.1674/0003-0031(2005)154[0412:PCITWN]2.0.CO;2

Shine, R. (1978). Sexual size dimorphism and male combat in snakes Oecologia, 33 (3), 269-277 DOI: 10.1007/BF00348113

Saturday, January 15, 2011

Cottonmouth Myths I: Snakes Dropping Into Boats

            Some animals just can’t get a break.  Cottonmouths, Agkistrodon piscivorus, (aka water moccasins) would like nothing more than spend their lives within their local swamp or river, either coiled up under a bunch of vegetation waiting for a hapless frog to paddle by, or perhaps patrolling the water’s edge at night looking for some other tasty morsel.  But, we all know that aquatic habitats, although preferred by many a swamp creature, are also popular areas for human recreation.  Every day, thousands of people fish, boat, swim or tube in wetlands that are prime snake habitat.

             Despite this shared affinity, there’s not much else that people and snakes have in common, with the possible exception that neither are often very happy to run into the other.  For many people, fear of getting bit by a snake is of tremendous concern.   Cottonmouths are potentially dangerous animals, but after working alongside (and with) these animals for the past few years, I’ve concluded that to get bitten by one you would either have to be very unlucky or…well, tend to make poor decisions.

            When I’m near a swampy area, I never wear open-toed shoes or sandals and I’m always cautious to watch my step.  But, the number one piece of advice I can offer to those who don’t want to get bitten by a Cottonmouth (or any other venomous snake, for that matter) is to never try to catch, kill, or otherwise bother these animals.   There’s a reason why the number one place for a person to get bit by a venomous snake is on their hands, and it is not because they have Cottonmouths in their pockets.

If you keep your distance from Cottonmouths, they have nothing to gain by attracting your attention.  They’d rather you don’t even notice them.  Even if you were to harass one of these animals, their first instinct is not to bite, but to flash their namesake white mouths to warn you.  Yet, some of the most pervasive myths about Cottonmouths concern their alleged aggression and tendency to approach, attack, or even chase people!

One of these legends states that one must beware of Cottonmouths in tree branches overhanging rivers, as these animals are likely to drop into your boat as you pass beneath them.  I’ve never quite understood why a Cottonmouth would do this or what Phase II of the attack might be, but some might have you believe that after a Cottonmouth drops into your boat, it would then proceed to kill everyone within reach.  That is, of course, unless the snake is killed first.

Here’s the lowdown.  There are snakes that hang out in the branches overhanging rivers and they do sometimes drop out of them.  But they’re not Cottonmouths and the last thing they want to do is land in your boat.

Although Cottonmouths can climb trees, they seldom do.  On the other hand, Brown Watersnakes, Nerodia taxispilota, frequently crawl out onto sunny tree branches to bask and raise their body temperature.  On the East Coast of the United States, both snakes have very similar and overlapping distributions (the Cottonmouth can be found farther west than the Brown Watersnake).  At first glance, these harmless water snakes might look a lot like a venomous Cottonmouth, but there are some considerable differences.  The Cottonmouth has pupils like a cat, a much chunkier body and a boxy head, but you may not remember these differences when your day of river relaxation is interrupted by a snake falling in your lap.

Why would a snake do that?

Watersnakes, as their name suggests, are most comfortable in the water and that’s where they frequently head when they’re scared.  A Brown Watersnake would be a fitting meal for most passing hawks, so when these serpents are alarmed, their first instinct is to drop into the water where these birds (or other predators) can’t nab them.  Now, a scared snake is a scared snake, and they’re probably not paying close attention to just who is doing the scaring; so, if you’re casually floating down the river and you startle a Brown Watersnake, it’s going to try to escape into the water.  And, if you got close enough to this snake before it noticed you, your boat may be between the snake and the safety of the water. Believe me, this snake does not want to fall in your boat; it wants to fall into the water so it can swim away.

This is a young Brown Watersnake

I’ve heard a few stories about “Cottonmouths” falling into boats and canoes, and these stories usually result in the panicked sailors capsizing or using a shotgun to kill the offending (and likely also panicking) snake.  Unfortunately, the latter option invariably leads to a big shotgun blast in the bottom of the boat.  Incidentally, if the snake were still alive, they could likely escape through this new renovation.  As I alluded earlier, this isn’t the only Cottonmouth legend (can I say myth?) floating around out there; we’ll tackle the rest later…

I plan to write future columns about Cottonmouth "breeding balls" and their alleged tendency to chase people.  I've already tackled the longstanding myth that baby snakes are more dangerous than adults.  Am I forgetting any Cottonmouth myths?  Have you witnessed something along these lines?


This isn't the first time I've written about Cottonmouths.  I wrote about how these snakes are quick to show up when a lot of toads (= food) appear here.  I've also written about accompanying Cottonmouth researchers as they wade through swamps to catch snakes in the spring as the reptiles try to take advantage of the new warmth and at night in the summer as the venomous snakes swam around me.  Finally, I provide some tips on recognizing Cottonmouths from non-venomous watersnakes here.

Cottonmouth pictures provided courtesy of Fingerprince Prints.

Much of what I write is based on my experience in the field, however I also rely on the research of others, citations of some relevant scientific articles are below.

M. S. Mills, C. J. Hudson, & H. J. Berna (1995). Spatial ecology and movements of the brown water snake (Nerodia taxispilota).   Herpetologica , 51, 412-423

Glaudas, X., & Winne, C. (2007). Do warning displays predict striking behavior in a viperid snake, the cottonmouth (Agkistrodon piscivorus)? Canadian Journal of Zoology, 85 (4), 574-578 DOI: 10.1139/Z07-025

Sunday, January 9, 2011

Orange You Glad That This Is A Perfectly Normal Alligator?

   The internet is abuzz with news of an orange alligator spotted in Venice, Florida.  News stories are popping up not just in Florida but everywhere from Los Angeles to the United Kingdom.  Nameless experts explain the beast is nearly an albino and extremely rare, other outlets breathlessly exclaimed we could be watching evolution in action.

  Fortunately, there were voices of reason at the Florida Fish and Wildlife Conservation Commission; they explained the animal's color was likely due to something in the water.  Maybe it was clay or mud.  When I was trapping turtles in New York years ago, I would occasionally visit ponds with water stained from naturally occurring sediment. As you might expect, the turtles I caught in these ponds were colored differently from those I caught elsewhere.  I remember one even appeared red.  It didn't occur to me at the time to call the newspaper (although I certainly don't fault the average interested citizen from doing so, an alligator that appears orange isn't something you see every day)!

 Alligators often swim with the top of their snout above water.  In the first picture you can clearly see this part of the animal's body isn't as "orange" as the rest.  The lower portion of the tail also appears more normally colored, perhaps this is because alligators often swim using their powerful tail muscles and this part of the body comes into more frequent contact with rocks, logs, and vegetation.  This would have wiped off the orange-causing culprit.

  The color became more pronounced because the alligator was basking to raise its body temperature and its skin dried.  In the second picture you may notice it doesn't look so strange where it is wet (the back half of the body).

 Evolution in action?  I don't think so.  Sounds more like a slow news day made more interesting by inserting sensational headlines.  The story may not be as outrageous as other tales you may find of alligators online but it does seem silly to make such a fuss about a tinted alligator.  There are enough fascinating biological attributes of alligators that are actually true to make for a good story without resorting to observations of odd colors.  Let's hope this alligator's newfound celebrity doesn't lead to anyone trying to feed it, or it is likely its 15 minutes of fame will be up very soon.