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Snakes Don’t Need Hearing Aids

We all have heard that snakes are in fact essentially ‘deaf’ as they have no external ear with which to channel the vibrations of sound into an inner ear. This being the case it would seem to be a ‘mistake’ for evolution to allow for the development of a noisemaking device on the terminal end of an animal which will never hear it in the first place right? I mean how would it know if it was making sound? Why make the sound in the first place if the animal it was attached to couldn’t tell if was doing them any good?

Well, snakes have an inner ear with a functioning cochlea. This means, according to the study done by J. Leo van Hemmen and Paul Friedel at the biophysics Department of the Technical University Munich and Bernstein Center for Computational Neuroscience in their work with their colleague Bruce Young of the Biophysics Department of Washburn University at Topeka, that snakes can ‘hear’ and locate prey using the vibrations on a sandy surface. When the snake lays its head on the ground it can pick up these vibrations and then locate the source of the ‘sound’.

As with all of nature there are no ‘mistakes’ only those things which we have yet to comprehend. To understand the rattle of the rattlesnake we can look at many reasons for it, such as a device for communication, but science has shown, at least so far anyway, that the keratin created rattlesnake tail is not used for intraspecies communique. So what reason could there possibly be for what essentially is a maraca on the tail. To our current understanding of the Crotalinae it would appear as though this rattle is used as a warning to other species that a potentially dangerous creature is near by.

For all of our studies of rattlesnakes it would appear that their primary defense would be crypsis. This essentially means that through evolution certain characteristics have been promoted and others not so that the snakes outline can be broken up and camouflaged in its surrounding area. Avoiding detection by predators. Crypsis doesn’t always work however, so what is a venomous snake supposed to do when faced with a six hundred to one ton beast? Well, you make noise right? According to at least one idea this could very well be the case.

Silent rattlesnakes?!

There is a species of rattlesnake the Catalina Island Rattlesnake Crotalus catalinensis which is the only known species of rattlesnake which has no rattle as do its 34 counterparts which make up the Crotalus genre. From what I have heard, there are two ‘theories’ on why this is. One says that because no bovines or large animals are present nor have there been in some time the rattles were not necessary so they evolved to not have rattles.

Another ‘theory’ I have heard is this is an adaptation for hunting birds. I looked for further reference to this theory but found nothing and to be honest I didn’t pursue it that far as this to me is one that doesn’t deserve much credence. I say this because as anyone who has ever worked with rattlesnakes knows the rattle is silent unless it is in action by the snake. When sitting still (as ambush predators do) there would be absolutely no reason for the tail to move and make noise so I am not clear as to why a rattlesnake without a rattle would serve for hunting birds, as the rattle is used as a warning and rarely makes noise when not being used as such and if it does I don’t think it loud enough to be evolved or phased out as hunting mechanism for birds. Who would be presumably skittish at sounds etc.

Here we come again to the original question

‘Are rattlesnakes adapting or ‘learning’ to go silent instead of buzzing at the feel of impending doom echoed through the booted heels striking upon the ground nearby?’

The Learning Reptile

Reptiles are too stupid to learn, or are they? What is intelligence after all? Intelligence as measured human primates usually starts with the human primate at the apex and then delineates from there. The humans are writing the text; we are naturally inclined to put ourselves at the top. Obviously, we are the most intelligent when we are writing the literature.

Can reptiles ‘learn’ novel behaviors? Yes, many species have shown the ability to acquire novel behaviors. Some monitor lizards have learned to access food that has been placed in a sort of puzzle. Most studies to my knowledge have been focused on monitor lizards or tortoises.

This doesn’t mean that snakes are not cognizant as many would believe. In my own piece on The Cognitive Reptile I referred to Laurence M. Klauber who spoke of his rattlesnake collection possibly being able to distinguish between himself and colleagues who entered his snake collection room. He claimed this due to the fact that when he entered alone the rattlesnakes did not sound off but when his colleagues entered the rattlesnakes would sound off. This has also been my personal experience with rattlesnakes that I have owned over the years. It has also been reported by numerous keepers of rattlesnakes that the rattlesnakes will not sound off at the approach of their caretaker but will sound off at strangers. This reported behavior alone would cause me to infer that snakes can and do learn on some level.

The Communicating Reptile

Dr. Rulon Clark of San Diego State University published a paper in 2007 Public information for solitary foragers: timber rattlesnakes use conspecific chemical cues to select ambush sites. This study states essentially that the timber rattlesnake Crotalus horridus uses chemical cues left behind not only by their own species but also by conspecifics as well and from this are able to ascertain which ambush sites would lead to better prey. In another paper Pursuit-deterrent communication between prey animals and timber rattlesnakes (Crotalus horridus): the response of snakes to harassment displays Dr. Clark discusses the predator prey communication system where when rattlesnakes are discovered by potential prey items they are harassed until the point of being driven away to another ambush site but this harassment is not always physical it can also be vibrational. Therefore there is actual communication happening between two conspecific animals wherein there is an actual informational exchange and understanding.

With the above information it is completely plausible that the rattlesnakes that are being hunted for roundups have learned, at the approach of footsteps not to sound off. Sounding off as it were exposing them to predation. If the hunters are indeed only taking the noise making rattlesnakes then that leaves a population of those that remain silent at the approach of footsteps. This creates an issue of safety not only for the unaware hunter of rattlesnakes but also the casual hiker or passerby whom may travel the same paths as the hunters. Potentially once again, humankind is creating their own perfect storm wherein more people can be injured due to ignorance and unwillingness to actually educate themselves regarding the natural world.

Round-Up

Round-up is the term to which persons who participate in the event call it when you go in search of wild rattlesnakes, capture them, and then bring them back to a predetermined locale. Once here they are usually thrown into the attention grabbing named “Pit of Death”. This is where there is a single individual walking about the hundred plus rattlesnakes that are being emptied into the arena and they are speaking into a microphone exhorting the educational ramblings of uneducated rumors and hearsay, rarely does any scientific matter get recited.

The typical behavior is to harass a rattlesnake or two into rattling to show off for the crowd so their is a real sense of impending danger to the person talking. The fun doesn’t stop there, oh no, there’s even more fun to be had. Some round-ups allow you to have your picture taken with a live rattlesnake! Have no fear, you’re completely safe.

You see the rattlesnake, prior to being slung around your neck has had its fangs removed with pliers and then just to be extra careful, the ever cautious round-up participant then places the rattlesnake into a chest of ice to calm it down. After it has calmed down enough, they then sew the mouth of the snake shut so when it is around your neck it cannot bite you. How kind is that, that the round-up participants are so concerned with your safety that they are willingly torturing and mutilating a live animal for your entertainment.

Round-up participants also claim that venom collected during round-ups is then sold to laboratories and used for research or in the production of antivenin. Numerous people will claim this as false and will raise questions such as wanting to see receipts of the venom sold etc. and from my personal sources which I will not reveal I have been told thusly. Large laboratories will in fact buy venom from round-ups. The reason that the person milking the snakes is not producing receipts is number one they legally don’t have to. Number two, the large laboratories that they are selling to don’t want to be associated with what really amounts to the wholesale slaughter of thousands of pounds of rattlesnakes ever year. Not to mention the fact that if the researchers found out they themselves may think twice of buying the venom from said laboratories.

Slaughter of rattlesnakes you ask? Oh yes, yes indeed. There is a special booth dedicated to the slaughter of rattlesnakes. At some round-ups, the kids can not only chop the head off their very own rattlesnake they can even put their hands in the blood and then put the bloody hand prints on  a wall of death! Sounds like a great day out with the family doesn’t it!

They even have contests to see who can bring in the most rattlesnakes, the heaviest rattlesnake, and the longest. Now then, think about this for a moment. Rattlesnakes or reptiles period generally do not grow very rapidly, for a rattlesnake to get to the large or longest prize winning size they would have to be an older snake. Taken one step further, rattlesnakes may have a home range from 160 acres for some Timber Rattlesnake Crotalus horridus horridus males to as little as 9 acres for gravid females.

Rattlesnakes of all species tend to have low productivity and even lower rate of mortality when it comes to their offspring. So if round-up participants are in fact hunting out the heaviest and longest snakes they are decimating a population even further by not allowing the population to recover. This is especially true when the round-ups are an annual event. The round-up participant is now going outside of the designated round up areas and gathering snakes which are sometimes hundreds of miles away from the round up locations. These rattlesnakes are then kept for days without food or water being provided. Did I mention that in most states the type of treatment that the rattlesnakes receive is actually a felony? This of course goes without mentioning that the local law enforcement is in attendance to keep an eye on the crowd. Now read this again carefully. Local law enforcement is on site and there are felonious activities being witnessed by said law enforcement and no arrests are being made. That just seems odd to me, to say the least.

It’s in the Numbers

Over the span of ten years almost 50,000 rattlesnakes have been tortured and died at the hands of the Sweetwater, Texas Rattlesnake Round-Up where they hold the worlds largest rattlesnake round-up and it has been reported on several occasions that the round-up participants are actually bringing the snakes from hundreds of miles away, as they are unable to find them in the local areas specified for round-up participants. Something which I found personally interesting, the years when there were spikes in numbers of rattlesnakes collected in Sweetwater, TX there were spikes also in rodent borne diseases such as lyme disease. I am no researcher but there does seem to be a correlation there of some type.

One thing is absolute fact. Rattlesnakes are a part of the ‘pest’ control system which evolved without mans intervention. We have seen numerous times how humankind and their interference will or has already upset entire biological systems which were operating under their own natural regulatory systems until humankind entered. When we take away part of the biological system that has been in place for millennia in the end humankind will pay the price in some form or fashion.

What Can I Do? 

For starters you already have completed your first task. You have read this article. Now then, I would immediately go to the RARR Needs You page and donate to get our teams out to the round-ups to document and build a case against these barbaric practices even happening in the first place. The next step would be to join the RARR Group on Facebook and start talking with the folks there on who to contact and how to make contact etc. Finally, make the calls, write the letters, and send the emails to those who need to hear your voice.

Silence is NOT Golden

I have shown that by collecting the amount of snakes that are currently collected there could indeed not only be an ecological impact on the current environment but there could also be an unintended dangerous counteraction which could potentially harm many humans as the rattlesnakes are potentially falling silent at the approach of humankind. Silence is not golden, these animals need the same amount of respect as do any other species on the planet. Do your part now and get involved.  

References:

Manrod JD, Hartdegen R, Burghardt GM. (2008) Rapid solving of a problem apparatus by juvenile black-throated monitor lizards (Varanus albigularius albigularius) Anim Cogn 11:267-273

http://www.dnr.state.oh.us/portals/9/pdf/pub375.pdf

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Berber Skink- Eumeces schneideri

I thought I would kick off with the Berber Skink, not only because I think they make awesome pets but they have quite a large natural range that has very similar climatic conditions. Berber Skinks are a medium to large skink growing to sizes of 30 cm total length. They have a range quite large from Tunisia and Algeria in North Africa right across to Tajikistan in Central Asia.

Rough Geographical range of Eumeces schneideri

The Koppen-Geiger Climate Classification uses average annual, monthly temperatures and precipitation to determine the climate of specific areas of the world and can be used to determine the type of land and climate in which and animals range may fall. Several different classifications exists and 90% of the Berber skinks natural habitat is classed as being within the BWh range. This is an area that exhibits hot, arid desert land that is too dry to sustain any vegetation apart from sparse shrubbery. Some of the range falls into the BSh classification which experiences a slight increase in annual precipitation. Summer temperatures between April and September range from between 20.5 centigrade to 30.0 centigrade and can drop to as low as 10 centigrade in winter, although there is no need to replicate this low temperature in the vivarium. A winter cooling to around 18 centigrade is fine. Wild Berber Skinks would experience a long hot summer with very little rainfall. Most of the rainfall across their range falling between November and March and most areas in the BWh range will experience less than 250mm of rain per year, some areas experiencing non at all.

Most of the Berber Skinks habitat is found on stoney, semi desert regions of hard compacted ground scattered with sandy deposits. Berber Skinks will be seen basking on larger rocks and boulders and this can be replicated in the vivarium. As a substrate a mixture of clean sand and orchid bark or eco-earth type substrates work great. Plants that would be found in these semi arid areas would be mostly xerophytic plants, those that have developed to require little moisture such as succulents and cacti species. Due to the digging capabilities of these skinks I would advise using artificial plants in the vivarium.

This is not in any ways a complete care guide to Eumeces schneideri, it is simply a quick look at the wild habitat and geographic distribution of the Berber Skink. Lots more information can be found about the captive care of these skinks and we would always recommend that several care guides and books are read before purchasing any animal.

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The statement I am referring to is ‘buy a smaller enclosure first as the reptile can become lost and not find its food.’ Really? I mean seriously folks, when was the last time you saw a reptile in the wild eating out of a food bowl? Is there a special store for snakes to obtain frozen thawed rodents that we have yet to find? This of course goes without saying that the vitamin and mineral shops in the reptile world must be making a killing by now. As my reviewer so carefully pointed out, I am not saying that you don’t have to feed vitamins and minerals. You absolutely must, you will see later in this piece that we cannot fully replicate the natural diet so we have to use supplements in order to ensure the reptile is getting the proper nutrition.

Nature 

All kidding aside, whether a reptile is captive bred or wild caught they have the instinct to  obtain nutrition as this is an over riding factor for survival. Let me clarify, some wild caught reptiles, will not adapt to the captive environment. There could be a multitude of factors at work to cause this. The biggest factor, in my observations is that of recreating the natural habitat. Reptiles are relatively a solitary animal insofar as they don’t share resources in the wild. Komodo Dragons Varanus komodoensis will ‘share’ in a kill and some species of reptile will stack on top of one another in the same basking area. However, there is a definitive hierarchy order to these behaviors. What I am specifically referring to is that after reptiles are born and move off from the parents they are for all intents and purposes on their own for the rest of their lives.

Reptiles, unlike birds and mammals are ill equipped to provide food for their offspring, the young must find it on their own. If they don’t find food, they die. This is the law of the land so to speak and a prime example of one of my old bosses statements “Even the stupid ones survive in captivity.” It is my view that even the stupid survive because as humans we will intervene as it were to make sure the animal survives.

I want to point out that all animals in the wild have a home range where they are able to discover the resources needed for survival. If they are unable to find these resources then they will inevitably perish. We can argue for days that this speaks to cognitive ability, whether learned or instinctual and that really is for another piece. This could also be viewed as survival of the fittest as the one who discovers the resources will obviously survive.

In my recent article 3 Reasons your Reptile Won’t Eat! I stated that security is one of the paramount concerns to snakes. This is because after feeding they will attempt to retreat to a warm basking area to digest their meal. This has been observed both in the wild and in the captive environment. Even what I refer to as active foraging snakes such as Racers and other species are known for their active foraging will seek out a warm basking area to digest a meal just as a sit and wait snake will move off from the ambush position to seek an area to bask in.

Nurture

Some argue that baby or juvenile snakes have exhibited issues in procuring food that is provided in the enclosure with them when they are housed in a ‘large enclosure’. Then when these same snakes are moved to a smaller enclosure they are able to obtain the offered prey and thrive. To my mind not knowing whether live or pre-killed is being fed; the predator vs. prey relationship should be looked into. I am looking at this from an analytical side, if this snake were in the wild and refused to eat it would perish.

The weak in the wild die and therefore are unable to pass on what may be considered bad genetics. If an animal cannot survive due its inability to obtain resources needed for survival should we interfere? Now then, breeders use their knowledge of genetics to breed for colors, patterns, etc. but is it possible we are breeding for weakness by interfering by making sure that these babies are feeding as we want them to and not allowing them to perish as they would naturally? I am sure some readers will be offended by that statement, the fact of the matter is in the wild babies rarely survive to adulthood and this is why animals have multiple offspring so that at least one and maybe more might survive. So breeders let me ask you this, is this a moral quandary or a financial one?

Observations in Nature & Nurture

In my observations in a naturalistic enclosure (not a sweater box or a rack system) that recreates the animals natural environment they tend to thrive better than those kept in other enclosure set ups. I have not done extensive studies on this, these are only my observations. Sure the reptiles will survive in sweater boxes and rack systems and they will reproduce too. Are they thriving though? Why do we have overweight reptiles? Because they don’t have to forage! They are locked away in an enclosure being lazy. Not to mention the fact that the diet we feed is nowhere near what they find in the wild. Yes a mouse is a mouse, most snakes in the wild are eating a variety of foods not just rodents, I have read reports of what we consider rodent eaters in captivity consuming bird and lizard prey in the wild as well as carrion when available.

My conclusions on reptile foraging in captivity is that it must be encouraged and that we as herpetoculturists allow the weak to die out as would happen in the wild. I do believe strongly that the genetics being passed on when we interfere by accommodating a weaker reptile who cannot ‘find’ its food in a large enclosure when all other parameters are being met should be let go. Yes there is the dilemma of when to give up just as there is with our own species, when do you pull the plug on life? Given the proper parameters for survival I can say that more often than not the reptile will find its resources such as food and water. If it doesn’t, then I think we are forcing an animal to live that would have under any normal circumstances passed away. Do we have the right to play God? I look forward to hearing your intelligently written comments.

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