Why we need reptiles…

I am a big advocate for conservation and the need to save the world’s threatened and endangered species. All species for that matter. When I talk to people about saving animals and living sustainably I am always confronted with one question. Why? Why should we save animals? Why do we need to save rainforests? Why do we care if one species goes extinct? And the “whys?” go on and on. When I explain these “whys” many people can understand to a degree and go “Oh that makes sense” but when we get to the subject of reptiles most have a hard time of it. They just don’t understand why a reptile could be important and especially why reptiles are important to themselves in particular. In this post I am going to try to explain to the best of my ability and knowledge why we need reptiles in this world. Feel free to comment with questions, concerns, and what reasons you may have for or against the conservation of reptiles.

Niche

In ecology, a niche is the role of an organism in the ecosystem within which it lives. We recognize two aspects of a niche. The first is an organism’s fundamental niche which is defined as the range of environmental conditions in which a particular species can survive. Essentially, the fundamental niche is every possible place a specific species could live. The second aspect of niche is the realized niche which is define as the area in which a species actually exists. The realized niche is caused by interactions with other organisms and other biotic constraints that do not allow a species to fill its entire fundamental niche. The realized niche is the role within an ecosystem for which that particular species is most suited to fill.

Just like every other organism on earth, reptiles play an important role in the ecosystems within which they exist. Some are predators, some are prey, and some are both. Some reptiles perform important ecosystems services and act as keystone species. Keystone species facilitate the existence of many other species in their respective ecosystems. Some examples are as follows:

American Alligators (Alligator mississippiensis):

Alligators create “gator holes” which in the hot months of summer tend to be the only areas left that have standing water. As you all know, water is essential for all organisms on earth. In the dry seasons water can become very scarce so these “gator holes” provide a refuge for many fish, turtles, and other aquatic organisms as well as a drinking hole for terrestrial life such as birds and mammals. Alligators facilitate the survival of organisms within such ecosystems.

Gopher tortoises (Gopherus polyphemus):

Gopher tortoises get their name from the deep burrows they dig much like that of a gopher. These burrows can be quite large reaching lengths of 5 meters long and 2 meters deep. These burrows provide the gopher with a refuge from wildfires, extreme heat, the winter cold, and predators. The awesome thing about gopher tortoises though, is they share these burrows with up to 350 (maybe even more) different species including burrowing owls, numerous rodents, rabbits, opossums, venomous and nonvenomous snakes, many amphibians, and pretty much anything else that needs a place to hide. The habitat that these tortoises provide is irreplaceable but sadly, like many reptilians, gopher tortoises are in decline and the ecosystem services that they provide will disappear with them if they cannot be saved.

These are only two species but two of the most well-known for providing ecosystem services.

Medicine

I will move of away from reptiles in their environment and bring things a little closer to home. One thing that I think we can all agree on is that medicine is very important. Advances in medicine have increased our quality of life as well as our life expectancy. Most medicine in part is derived from something that was found in nature. Reptiles interestingly enough provide some very useful medicine mainly through their venom. I would bet that most people have used medicine derived from reptile venom (primarily from snakes) and didn’t even know it.

The two broad classes of snake venoms are hemotoxic venom and neurotoxic venom. Hemotoxins primarily effect the blood and mechanisms associated with blood such as the ability of the blood to clot. Hemotoxins usually contain a necrotizing component as well which cause the death of tissues. Neurotoxins primarily effect the nervous system as their name suggests and many times can cause temporary or permanent paralysis.  As you can imagine hemotoxins are usually used to treat ailments pertaining to the blood. The first medicine derived from venom was made from a protein in the hemotoxin produced by a Brazilian pit viper and was used to treat hypertension (high blood pressure). If you have ever heard of an ACE inhibitor then you have heard of this protein. In the 1970’s scientists were able to produce a synthetic version of this protein that is now used in many different blood pressure medicines. Just in case you didn’t get it, this discovery was VERY important.

Other drugs created from venoms include eptifibatide and tirofiban both of which are used to treat minor heart attacks and chest pain. They do so by dissolving blood clots. Similarly, new drugs are being tested to help treat strokes by dissolving blood clots. Southern copperhead venom contains a protein called contortrostatin that has been shown to suppress cancer growth by binding to tumors disallowing them from spreading. Human trials are probably a ways off but there is much hope surrounding this discovery.

So far I have been talking about snake venoms but I don’t want to forget about lizards. Exenatide is a diabetes medications that was synthesized from Gila monster (Heloderma suspectum) saliva. This drug helps to sustain glucose levels and increase weight loss which is a common factor in controlling type 2 diabetes.

Many more medicines exist and are in the works and if you would like to learn more about them you can visit The World Toxin Bank. Also, check out the Facebook group The Venom Interviews where experts in the field discuss the latest news and research pertaining to venom.

Aesthetics

Now most people probably think I am crazy when I say that reptiles are in fact beautiful and contribute to what humans find so aesthetically pleasing about nature. When most people think of reptiles they think of slimy, scaly, ugly creatures but what most people don’t realize is that many reptiles are actually quite colorful, ornately patterned and adorned, and spectacular to look at. Some examples are as follows:

Red Milk Snake (Lampropeltus triangulum syspila)

Eastern Box Turtle (Terrapene carolina)

Banded Watersnake  (Nerodia fasciata)

Big Headed Anole  (Anolis capito)

Malaysian Blue Coral Snake (Calliophus bivirgatus)

Diamondback Terrapin (Malaclemys terrapin)

Panther chameleon (Furcifer pardalis)

West African Green Mamba (Dendroaspis viridis)

Burmese Starred Tortoise (Geochelone platynota)

Fan Throated Lizard (Sitana ponticeriana)

Green Bush Viper (Atheris squamigera)

Peninsular Rock Agama (Psammophilus dorsalis)

This is an extremely short list which could go on and on and please note that that if you click on the names it will take you to a google search as unfortunately I personally don’t have photos of many of these amazing reptiles. Feel free to comment and post other beautiful reptiles.

Economic Importance

It is very hard to place an economic value on reptiles outside of the pet trade mainly because the services they provide are behind the scenes and can only be calculated after reptiles have been extirpated from an area. However, reptiles can be very important when it comes to pest control. Many lizards help in controlling insects that can destroy crops and can be quite annoying to humans such as mosquitos.  Snakes may provide the biggest service by controlling rodent populations. It has been shown that after the disappearance of certain snake species from an area rodent populations explode. These elevated populations of rodents can have devastating effects on crops and not to mention the carry some very nasty diseases that can be passed to humans. Personally, I’d rather have one big rat snake hanging around my house than an entire community of mice. So there, reptiles help reduce and control other annoying animal species that people don’t seem to like much. Considering how often you run into mosquitos and other insects and rodents while reptiles are present just think of how awful it would be if reptiles disappeared. We’d be up to our elbows in mouse poop and our heads would be one big mosquito bite. I’ll take the reptiles.

This is a small attempt at explaining the need to save our reptilian species. I welcome and encourage any opinions (for or against) that people may have on this matter.

The Serpent: Part One

Snakes are some of the most interesting creatures on this planet. They happen to be my favorite type of animal, which is of course why I chose to explain them in detail first. From my overview we know that snakes are lizards which are something that many people probably have a hard time accepting after all these years of having them separated. Previously it was thought that snakes and lizards merely shared a common ancestor and while that is still true we now recognize that snakes are so similar to lizards that they are just another type of lizard.

So if we think of them that way then snakes don’t seem so scary, right? Well unfortunately, that’s not right. Snakes are some of the most reviled animals on this planet. People seem to be born with the fear of snakes and it is widely accepted that our primate cousins actually do have an innate fear of these animals which could explain why so many people are afraid of snakes. The problem is that snakes are subject to unwarranted persecution because of this fear. In a later post I will go into some of the common beliefs about snakes that seem to fuel people’s hatred towards the serpent. But first we will learn what exactly makes a snake a snake.

Eastern gartersnake (Thamnophis sirtalis) from the upper peninsula of Michigan.

Phylogeny

Snake classification has changed a great deal over the years. In the beginning snakes were classified purely on their external characteristics and because of their extremely different appearance they were placed in a class all their own. Linnaeus put them into a group called Serpentes in 1758 which included only three genera and 200 species. People would later add more species and divide them into more distinct groups based on differences in external form but it was not until the mid-1800 when skull features were used in classification. After this, others began examine internal structures of snakes to search for relationships. Garth Underwood’s paper A Contribution to the Classification of Snakes in 1967 paved the way for what would become the modern approach to snake classification.

More recently evidence shows that the first snakes diverged into the groups, scolecophidians and alethinophidians which include the blind snakes and all other snakes respectively. The phylogeny of the scolecophidians is well resolved but the same cannot be said for the alethinophidians and debate is still ongoing about where exactly each group should be placed. Even within all this debate it was well accepted that snakes were sister taxa to lizards meaning that they shared a common ancestor but have evolved into separate groups. Most people still think of snakes in this way today however, new evidence using mitochondrial DNA among other factors actually place snakes within lizards. The general consensus now is that all snakes are in fact lizards but not all lizards are snakes.

Eyelash pit viper (Bothriechis schlegelii) from Costa Rica

Morphology

Now that we know a little bit about where snakes come from in terms of their evolutionary history let’s talk about what makes a snake a snake. All snakes are limbless, meaning that they have completely lost their legs. Essentially, they are an elongated tube facilitated by the increase in the number of vertebrae and ribs. Most snakes range between 120 and 240 vertebrae but some can have over 500. Because snakes have so many vertebrae and are so long their bodies are extremely flexible and able to twist and turn in any direction

Snakes bodies are covered in scales like all other reptiles and they shed their scales in one piece as they grow by crawling out of it. Before they are ready to shed, fluid builds up underneath their skin making the eyes a milky color. Right before they shed the fluid goes away and they crawl out of their skin by rubbing up against objects in their environment. There is even a scale cover their eye called the spectacle that is shed with the rest of their skin. The scales on the snakes’ body provide them with protection and help to prevent water loss. The adaption of scales was one of the factors that allowed reptiles to move away from water early in their evolution.

False fer-de-lance (Xenodon rhabdocephalus) from Costa Rica

Distribution

Snakes exist on every continent except Antarctica. They do not range to the very far north either. Snakes are absent in most of Canada only existing in the southern portions. Northern Russia also seems to be devoid of snakes. This is because like all reptiles snakes rely on the external temperature to heat their bodies and have not adapted the capabilities to live in such cold environments. In later posts I will talk about some reptiles that have some extraordinary adaptations for living in the cold.

Venomous snakes have exists on every continent as well and are nearly as wide ranging as non-venomous snakes. Sea snakes live in the ocean around the mid latitudes and are found in all marine waters except for the Atlantic and the Arctic oceans.

Behavior

The way that snakes eat is probably one of the most intriguing things about them. Lacking any limbs to aid in feeding they have developed some very interesting strategies to consume food. All snakes swallow their prey whole because they cannot rip or tear their prey apart. Many snakes use constriction to subdue their prey. They do this by striking prey and grabbing them with their mouth and then coiling their body around the animal. Every time the prey exhales the snake tightens its grip until the animal suffocates. Other snakes use venom to subdue their prey. The venom is injected via specialized fangs and usually kills the prey very quickly. After the prey dies the snake tracks it down and consumes it. Some snakes will even consume their prey while it is still alive, such as snakes that eat very small prey or prey that cannot actively try to escape.

Snakes also have numerous defense behaviors. The hognose snake (Heterodon platirhinos) is probably one of the best known snakes for its array of defense behaviors. These snakes will puff themselves up and spread the skin around their heads to make themselves look bigger. If that does not work they will often roll onto their backs and play dead. To further add to the effect they will emit a very foul odor that smells somewhat like a rotting animal. Interestingly enough, you can actually flip these snakes back over only to have them consequently roll over onto their backs again. Seems hognoses haven’t quite figured out that dead snakes don’t usually do this. These snakes will also feign striking but rarely ever bite.

Other snakes show similar behaviors to deter predators. Most will emit a foul smelling musk from their cloaca if perturbed. A very well-known defense behavior is when a cobra flattens out the skin around its head into a hood to make itself seem bigger. They often will raise the front third of their body off the ground as well to add to the effect. Rattlesnakes are best known because of the rattle that they carry at the tip of their tails. When shaken the rattle makes a loud buzzing noise to alert predators to stay away. Many snakes mimic this tactic by vibrating their tails against dry leaves which achieves a similar sound.

Timber Rattlesnake (Crotalus horridus) from Indiana.

Locomotion

As I mentioned above a snake’s many vertebrae allow them to move every which way.  This flexibility in movement has allowed for a few different types of locomotion. One of the most common forms of locomotion is called lateral undulation, or a wavelike, motion which can be performed on land, in water, and even within trees and bushes. This is the typical movement associated with snakes but others do exist in certain species. Some snakes such as the sidewinder take undulation to a whole new level by turning sideways and drastically exaggerating the undulating motion. This type of movement is called sidewinding and helps snakes to move on sand as well as keep only a portion of their body on sand because it is so hot. Another type of locomotion called concertina involves pulling the body up into bends and then straightening out in an accordion like pattern. Rectilinear locomotion is used by larger snakes such as pit vipers, boas, and pythons. These snakes tend to move in a straight line by inching their belly scales along. They do this by lifting up parts of their belly scales and moving them forward in a wavelike pattern and then setting them down and pushing against the ground. The last type of movement is called side pushing. This type of movement is usually used by snakes that are startled and cannot get enough traction against the surface they are on. They use large undulations of the body to hopefully find an object to push against that will help them move forward. Most snakes use a combination of these types of locomotion for any particular situation.

Check back later for common snake myths and the truth behind them!

The Timber Rattler

Pictured is a timber rattlesnake (Crotalus horridus). Timber rattlesnakes are one of the most widespread rattlesnakes ranging throughout most of the eastern United States.Photo Credit: Seth LaGrange