Snakes are probably the most unique vertebrates in the world. They are tetrapods by decent but has lost limbs during their evolution. Without the help of arms and legs, they are still able to hunt and eat all other vertebrates! Infact, not only do snakes eat other vertebrates, they swallow them whole!

There are around 2,900 different species of snakes, which are divided into several families. Snake taxonmy changes all the time as we learn more about snakes. Currently, some of the families of snakes are Boidae (boas), pythonidae (pythons), crotalidae (pit vipers), viperidae (vipers), natricidae (water snakes) elaphidae (cobras, kraits, etc), Hydrophiidae (Sea Snakes) and Leptotyphlopidaes (Slender Blind snakes). In years past, many snake families were listed as subfamiles under the family of Colubridae, but recent research suggest that many subfamilies should be lifted to family status.

Snakes are found on all continents except Antarctica. They swim in the world's warmest seas, crawl in termite mounts, sidewind in some of the hottest deserts and glide from tree to tree in Asia's tropical forests. The Lesser Antillean Threadsnake (Leptotyphlops bilineatus) is the world's smallest snake, while the Green Anaconda (Eunectes murinus)are considered world's largest snake and the Reticulated Python (Python reticulatus) is considered the world's longest snake. They come in many different colors, from hot pink to lime green, some feel really smooth while others feel like a file but they all have the same general body shape.

Unlike their close relatives, lizards, all snakes are carnivores. They eat things from terimites (threadsnakes & blind snakes) to 8 foot long Caimans (anacondas). They all do this without the use of limbs. When devouring prey, their bodies are used to hold and kill the prey, while still maintaining body functions like breathing and if the species is arboreal (tree dwelling), then body is also used to anchor their bodies in a tree. Diets of snakes include items such as spiders, crayfish, lizards, mammals (from white-tailed deer to shrews), birds, eggs (of all egg laying vertebrates), insects, amphibians (salamanders, frogs & toads), and fish. Some species are specializers, they only eat certain types of animals. For example, Eastern Hog-nosed Snakes only eat toads. Other snakes, such as coachwhips and garter snakes, will eat a variety of prey items.

One of the most interesting attributes of snakes is the venom that a small number of them possess. Of the 2,900 different species of snakes, only around 300-500 (10-17%) of them have venom that could harm humans. In the U.S., that number is even smaller; there are only 21 venomous snakes (15% of all U.S. snakes) that are dangerous to people. Several snake species, such as Black-headed Snakes, have venom that is open specific to arthropods and are considered harmless to humans.

Traditionally snake venoms are classified as neurotoxic or hemotoxic; but as science makes advances in venom research, herpetologists are finding out that many venoms have alittle bit of both. Venom first evolved as a food acquiring device. The venom of Western Diamond-backed Rattlesnakes will kill their prey items and then act to start digestion inside the prey. On the defense side, venom is used only as a last resort. Warming colorations (coral snakes), tail rattling (rattlesnakes, tail vibrating in copperheads & cottonmouths), open mouth threats (cottonmouths) and hissing (some rattlesnakes). Snakes actually will try to conserve their venom because it's costly to produce and can take up to two weeks to completely fill their venom glands.

Venomous snakes are dangerous, but one should learn to respect and appreciate them because they play an important role in the ecosystem. Of all the things that are dangerous to man, venomous snakes are at the very end of the list. Every year, there are roughly around 7,000 reported venomous snake bites in the U.S. , only around 15 or so results in a fatality. When you look at the big picture, venomous snakes are pretty tame compared to the number of human deaths caused by of smoking, alcohol & drug abuse, public shootings, and automobile accidents.

As the relationship between man and snake move in to the 21st century, we are at the crossroads. Less and less children are able to find snakes in the wild, but they still express interest and excitement when they meet them in the classroom. Thankfully, also gone are the days of boyscouts getting merits for killing watersnakes. But as we modernize, the connection between children and nature has been severed to the pointed where we must save "our children from nature-deficit disorder" (Louv 2005).

We are now at at stage where humanity and its byproducts encroaches on the last remaining areas were snakes live. As cities such as Houston, Texas gets bigger and bigger; their urban spawls are constantly consuming snake habitat. In Houston's Memorial Park, "wilderness" is surrounded by a sea of concrete. However, in that park rare inner city snakes such as Southern Copperheads & Texas Coral Snakes coexists with joggers, hikers, soccer players, dog walkers & mountain bikers in Houston's inner loop's only remaining large piece of native landscape. Sadly, this is one of the "happy" stories for snakes in cities; in most cities they have been pushed out.

Even in rural areas, snakes faces human impact. Besides habitat loss, busy roads have become a problem in some places. When there is a busy road on the path of a snake's migration or immigration route, roadkills can affect the snake population. For example, on a 15 mile stretch of Cow Creek road (30 minutes south of Houston), between 10 to 20 (up to different 10 genera) snakes are killed each night during the warmer months. Some argue that wildlife roadkill outside of the city is a byproduct of the urban life. As more people chose to find home outside of the city, and accept longer commutes; it brings their tires closer to wildlife. A normal 9-5 work day, 1 hour stuck in traffic, 30 minute commute to work/home and maybe quick trip to the grocery store after work; creates high road traffic on country roads during peak wildlife movement (1 hour before and after dawn/dusk). This creates a danger zone not only for reptiles, but all wildlife. Animals from Edith's Checkerspot to Ocelots are affected by road mortality. Large animals such as racoons, deer, elk and bear are often noticed by drivers, but many feel that small animals such as birds, rodents, reptiles & amphibians make up the bulk of the roadkill biomass (Forman, et al. 2003).

Believe or not, there is an upshot to all of this. Since the 1970's, there has been more and more research being done on snakes. There are field guides of snakes for several states (such as Snakes of Texas, Snakes of Florida, Snakes of California) and a textbook sized one called on Snakes of the United States & Canada. Most states have wildlife laws to protect threatened and endangered snakes. Dr. Harry W. Greene's dream of "a day when park rangers will proudly guide visitors to a Timber Rattlesnake den, when nature tourists will travel to Arizona or Costa Rica with hopes of seeing several species of pitvipers on one trip" will soon be realized (Greene 1997).

References