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Snakes - Strange Facts About Fascinating Reptiles
The Nature of Snakes
Snakes are fascinating animals. Their elongated, legless body is covered in scales and is well adapted for the animal's lifestyle. Snakes slither over or under the ground, swim in the ocean or fresh water, climb trees or glide through the air, depending on the species. All snakes have the same basic body structure and functions, but some have specialized features which are often strange or surprising.
Snakes are carnivores and hunters. Some are venomous and inject their prey with venom as they bite them. The venom travels through a channel in the teeth or down a groove on the outside of the teeth. Unfortunately, venomous snakes may bite humans when they feel threatened. The venom of some snakes is deadly. Luckily, venomous snakes comprise only a small proportion of the total snake population.
Snakes have bad to good eyesight. The so-called blind snakes spend much of their time burrowing underground. Their eyes are covered with opaque scales. Blind snakes can distinguish light from dark but can't see an image. Other snakes do see images, and some have good vision. Snakes don't have eyelids, however.
All snakes flick their forked tongues in and out of their mouths repeatedly as they explore their surroundings. The tongue picks up molecules from the air and inserts them into a structure called the Jacobson's organ in the roof of the mouth. This enables the snake to detect chemicals in its environment.
Snakes have nostrils, which send air to the lung (or lungs) and to an organ of smell. They don't have a visible, external ear flap, but they do have an inner ear which detects vibrations that are transmitted through the body.
Snakes belonging to the pit viper group have an additional sense organ. There is a pit on each side of their head between the eye and the nostril. The pits can detect infrared radiation, or heat. This helps the snake to detect the presence of warm-blooded prey nearby.
The Smallest Snake
The smallest snake in the world is the Barbados threadsnake, or Leptotyphlops carlae. It has an average length of four inches and is no wider that a strand of spaghetti. The snake has a shiny surface and is one of the blind snakes. Some people might mistake this animal for an earthworm, but it has the body structure of a snake.
The Barbados threadsnake was discovered in 2008 by Dr. Blair Hedges from Pennsylvania State University. He and his wife found specimens living under rocks in a forest. The snake is thought to feed on termites and their eggs.
The Longest Snake
The longest snake in the world is the reticulated python, or Python reticulatus. This snake may reach a length of thirty feet or more, but most individuals are shorter. The snake is nonvenomous and is a constrictor. It coils around its prey, preventing the prey from breathing and suffocating it. The "reticulated" part of its name comes from the beautiful net-like pattern on its skin.
The Heaviest and Thickest Snake
The heaviest and thickest snake in the world is the green anaconda, or Eunectes murinus, which may reach 550 pounds in weight,12 inches in diameter and 29 feet in length. Females are larger than males. The green anaconda lives in South America and spends most of its time in the slow-moving water bodies of the tropical rain forest, such as swamps and sluggish steams. The snake isn't venomous and kills its prey (mammals, birds and other reptiles, including caimans) by constriction.
The Green Anaconda
Snake Venom Facts
There are four types of snake venom.
- Neurotoxic venom affects the nervous system. It interferes with the conduction of nerve impulses and can stop the breathing process and the heartbeat.
- Hemotoxic venom stops blood from coagulating and increases bleeding.
- Myotoxic venom stops muscles from working properly.
- Cytotoxic venom destroys cells and tissues in the body.
A Spitting Cobra in Action
Which Snake is the Most Venomous?
It's difficult to name the most venomous snake in the world. Some snakes have a venom that is less powerful than the venom of other snakes but is more dangerous because it's injected in larger quantities, for example. Many snake venoms haven't been tested for toxicity. Another problem is that test procedures to determine venom toxicity vary in different labs.
An unpleasant laboratory test is used to determine the toxicity of a substance. It's called the LD50 test and measures the dose of chemical that is lethal to 50% of a group of laboratory mice. The lower the LD50 number, the more dangerous the chemical.
The usefulness of the LD50 test is limited. The toxicity of a venom depends on how it enters the body of a mouse. Injecting venom into muscle usually gives a different LD50 number from injecting it into a vein or under the skin. Not all labs perform their LD50 tests in the same way, which leads to confusion when interpreting the results. In addition, a given venom may not have the same effects in humans as it does in mice. Nevertheless, a winner in the most venomous snake contest has been announced, based on the LD50 test result.
The Inland Taipan or Fierce Snake
The Inland Taipan
The honor of the most venomous snake in the world based on LD50 values is often awarded to the inland taipan, or fierce snake, of Australia (Oxyuranus microlepidotus). The snake is a shy and reclusive animal, but it may bite if provoked. However, bites are rare, and all known bites have been treated successfully with antivenom (a medication that destroys snake venom in the body). Other snakes that produce venom with a higher LD50 value are actually more dangerous than the inland taipan because they live in areas with a larger human population or because they are more aggressive.
How to Distinguish Coral Snakes (Venomous) From King Snakes (Nonvenomous) in North America
Three Dangerous Snakes
Three snakes - the black mamba, the Egyptian cobra and the boomslang - would definitely be included on a list of the most dangerous snakes in the world. They are frightening animals, but they only attack humans when they want to protect themselves. Unfortunately, sometimes snakes hide when a human approaches, so the person may not realize the danger. The snake may then attack because it feels threatened.
Antivenoms are available for some snake venoms. Some venoms act so quickly that there may not be time to get the antivenom, however. This is especially true when someone is in a remote area when they experience a snake bite.
The Black Mamba
The black mamba (Dendroaspis polylepis) is the most venomous snake in Africa and is also the fastest snake in the world. Black mambas are usually green, grey or brown in color, but the inside of their mouth is blue-black. The snakes open their mouth to display its color when they're threatened. Black mambas are usually about eight feet long, although they may be as long as 14 feet. They can move as fast as 12.5 miles an hour.
Black mambas are generally shy but are very aggressive when they feel threatened. They lift their head and up to a third of their body off the ground during their threat posture. They also expand their neck flap, making them look larger, and hiss. Black mambas bite multiple times from many directions if their threat posture doesn't work, injecting a large amount of powerful venom into their victim. The venom contains a neurotoxin that blocks nerve conduction as well as a cardiotoxin that interferes with the heartbeat. Without antivenom, death occurs in about twenty minutes. Unfortunately, due to loss of the black mamba's habitat to humans, encounters between people and snakes are becoming more common.
Collecting Venom From a Black Mamba to Make Antivenom
An Egyptian Cobra in Captivity
The Egyptian Cobra
Like other cobras, the Egyptian cobra (Naja haje) has long ribs in its neck. The ribs enable the snake to expand the sides of its neck when it's alarmed, forming a "hood". The hood makes the snake look larger and more intimidating.
The snake's venom can kill a person in as little as ten minutes. Those ten minutes are very painful, since the venom contains neurotoxins that affect nerves and cytotoxins that destroy tissue. The neurotoxins stop nerve impulses from going to the muscles, including those of the heart and respiratory system. Death is due to respiratory failure. Symptoms of the venom attack include pain and severe tissue swelling. The affected person may also experience a headache, nausea, vomiting, abdominal pain, diarrhea and convulsions.
The Egyptian cobra is often said to be the "asp" that Cleopatra reportedly used to kill herself. Some researchers think that this is unlikely, however. Dying from the poison would be a horrible experience.
The venom of the boomslang (Dispholidus typus) is very toxic. It's a hemotoxin and causes internal bleeding and blood loss from the openings of a person's body. The person may notice blood in their saliva, urine and stool, as well as a bleeding nose. As the damage progresses, the skin may take on a bruised and bluish appearance due to blood buildup from the internal bleeding.
One good point about boomslang venom is that it's slow to act, giving someone time to find and administer antivenom. On the other hand, the gap between bite and noticeable symptoms may be a disadvantage, because the affected person may think that the attack has caused no problems and may not look for antivenom.
The boomslang lives in Africa south of the Sahara and has a variable appearance. Males are often light green and may have black markings as well. Females are often brown. Boomslangs are arboreal snakes, but they do travel along the ground at times.
The snake wasn't considered to be venomous until 1957. In that year Karl P. Schmidt was a well known herpetologist working at Lincoln Park Zoo in Chicago. He received a bag containing a boomslang and took the snake out to examine it. The snake bit him on his thumb, but Schmidt was unconcerned and didn't seek medical treatment until it was too late to help. By the afternoon of the next day Schmidt was dead. This sad event changed people's opinion about the safety of the boomslang snake.
A Boomslang in Kruger Park
Sea snakes are marine animals and are good swimmers. The sides of their bodies are often flattened, somewhat like a fish's body, and they have a paddle-shaped tail. These features help the snakes to move through the water and make them look a bit like eels. They aren't fish, however, and must surface to breathe.
Many sea snakes have very potent venom. Although some are aggressive, many are quite friendly towards humans. One sea snake that is definitely not friendly, however, is the beaked sea snake. Most deaths from sea snake bites are caused by this animal, which is described as having a "nasty" temperament. The snake lives around Asia and Australia. DNA tests indicate that there are two different species of beaked sea snake.
The Sea Krait
Flying snakes live in Southeast Asia. They actually glide instead of fly, but their movement is still amazing. They can even change direction while they're airborne!
A snake performs the following sequence of events in order to "fly".
- First, it climbs a tree and slithers to the end of a branch.
- Then it dangles its body from the branch in a J shape while gripping the branch with the back part of its body.
- The snake then uses the lower part of its body to launch itself into the air.
- As soon as it's airborne the snake forms an S shape with its body.
- The snake rotates its ribs forward to flatten the top part of its body and give its undersurface a concave shape. In this way it turns its whole body into a wing.
- The snake undulates its body in the air, which helps it to steer.
Being able to glide from tree to tree is very useful when a flying snake wants to escape from predators.
The Paradise Tree Snake Gliding in the Tree Canopy
The Interesting World of Snakes
There are many other snakes that have fascinating abilities and behavior. It's very interesting to observe them, although it's essential to keep far away from venomous species.
Snake videos are entertaining to watch - and safer, too, when the snake is venomous - and books about snakes are an excellent addition to a home library. Observing snakes in real life is the most enjoyable way to study them, though!
© 2013 Linda Crampton