The Ancient Dread

Reptiles evoke a strong reaction in people.  Fear, disgust, horror are all quite common responses to these cold-blooded creatures.  I am not in that group but when I come upon a snake by surprise, it can make me jump.  Think of the stories.  The serpent in the garden.  Dragons and maidens.  Man-eating crocs.  There are good reasons for these stories.  Snakes are a perfect embodiment of the other.  Cold blood, no legs, forked tongue, and some can kill with a bite.  The largest reptiles, the crocodilians, can eat us.  As David Quammen wrote in his book on top predators, The Monster of God, “It is one thing to be dead; it is another thing to be meat”.   The otherness, the fear of death or even the fear of consumption tint much of humankind’s view of reptiles. 

People have an innate, genetically based, fear of snakes.  Young children do not initially fear snakes but are very good at detecting them.  With a little training, that high degree of perception can turn to fear.  This leeriness had survival value for our ancestors and it is still with us today. 

A large Western Diamondback Rattlesnake (Crotalus atrox)
in Bentsen-Rio Grande Valley State Park, Texas

The largest venomous snakes in North America are the Diamondback Rattlesnakes. There are Eastern and Western species and these big snakes (Crotalus adamantus and Crotalus atrox) and they are the most dangerous venomous snakes in the United States.  Their great threat is because they can deliver a large dose of venom through their hollow fangs.  Diamondbacks are pit vipers, so named because of two pits that lay between their eyes and nostrils.   These pits are the snakes’ infrared detectors used to find their warm-blooded prey.  Pit vipers have broad heads and menacing eyes with vertical pupils. Diamondbacks usually consume small to moderate sized mammals, ranging from mice to rabbits. When a Diamondback Rattlesnake bites, the prey animal staggers off to die.  The snake tracks the stricken animal by its heat signature and smell, using its tongue.  When the unfortunate mammal is incapacitated, the snake eats it.  Diamondback venom works by interfering with blood clotting proteins, destroying red blood cells and damaging tissue.  Mortality for people bitten by the Eastern Diamondback is 10-30%.  Eastern Diamondbacks are listed as a species of least concern but the last Eastern Diamondback in Louisiana was seen in 1995.  The species may also be extinct in North Carolina.  Western Diamondbacks are more common but are also under pressure including rattlesnake roundups.  

A small Copperhead (Agkistrodon contortrix), showing its vertical
pupil split, Rowan County, North Carolina

In our part of the world, the most common pit viper is the Copperhead (Agkistrodon contortrix).  

Copperheads are handsome snakes with a brown background with a pattern of darker brown, irregularly-shaped stripes.  The head of this species is reddish-brown and gives the snake the name Copperhead.  Copperheads hunt small animals including mammals, other snakes and frogs.  Interestingly they have a real taste for cicadas, large insects that emerge each summer and fill the air with their songs.  Copperhead bites are painful but rarely fatal to people.  This is good because Copperheads have taken to living among people in rural and suburban settings.

A Common Snapping Turtle (Chelydra serpintina)
lumbering on land. Loxahatchee National Wildlife Refuge, Florida

Turtles generally do not elicit the repulsion or fear inspired by some other reptiles but Snapping Turtles are a special case.  The Common Snapping Turtle (Chelydra serpentina) is found in the eastern two thirds of the United States and southern Canada inhabiting freshwater lakes, ponds and streams.  Adult Common Snapping Turtles can reach a length of 18 inches and weigh over 35 pounds. Common Snapping Turtles have a large head with a beak, a long neck, a long saw-toothed tail and keels on the shell. It looks dangerous.  These turtles spend most of their time in water, but will come on land to move between bodies of water or to lay eggs.  Common Snapping Turtles are the top predator in their environment and consume fish, amphibians, small mammals and even plants.  Common Snapping Turtles usually do not bite people but have a fearsome reputation and will respond aggressively if picked up.    

The head of a Common Snapping Turtle.  Note the strongly hooked beak
and spines on the top of the head.

The tail of a Common Snapping Turtle with spines.

Alligators and crocodiles are the largest of the living reptiles and they are the most feared.  The American Alligator (Alligator mississippiensis) is native to the Southeastern United States.  American Alligators are black with wide heads and laterally compressed tails.  The males can reach 15 feet in length and weigh up to 1000 pounds.  American Alligators cruise the water with just their nostrils and eyes showing and that is a chilling sight.  These large reptiles were hunted to near extinction in the 20^th Century but their numbers and range have increased with protection. They eat anything they can catch including fish, crustaceans, snakes, turtles and mammals.  While human fatalities due to American Alligators are rare, they do have a taste for dogs.  

An American Alligator (Alligator mississippiensis) swimming
in a South Florida waterway.  Loxahatchee National Wildlife Refuge.

The silhouette of an American Alligator with its nostrils,
 eyes and spiny back above the surface of the water.
 Payne's Prairie State Park, Florida.

American Crocodiles (Crocodylus acutus) are even larger than American Alligators.  Large males can reach 20 feet and weigh up to 2000 pounds.  American Crocodiles are found in northern South American, Central America, Caribbean Islands and extreme South Florida.  American Crocodiles are lighter in color than American Alligators and have a pointed snout with teeth protruding from the lips.  Populations of American Crocodiles have increased in South Florida and they are now classified as threatened rather than endangered.  There are some documented cases of attacks on people by American Crocodiles and a few fatalities.  

American Crocodile (Crocodylus acutus) basking on the banks of the
Rio Tarcoles, Costa Rica.

An American Crocodile in the Rio Tarcoles, Costa Rica.  Crocodile's teeth
are visible when the jaw is closed.  

There is no question that some reptiles are dangerous.  When someone is bitten by a snake or attacked by an alligator there is a tremendous amount of public interest.  Around 20 people died of alligator attacks in the United States since the year 2000.  About five people per year die from snakebites.  Despite these relatively low numbers of fatalities, reptiles have an exaggerated place in our collective sense of danger.  I say, resist your ancient dread, be cautious, and enjoy the reptiles.