Venomous & Non Venomous Snakes

There may be as many as a half million bites and 20,000 deaths per year from snakebite worldwide (Kasturiratne et al. 2008). That figure is about half of the number of deaths attributed to venomous snakes worldwide when this book was originally published in 1965. In all probability, the death estimates are low, given that in many undeveloped regions of the world snakebite deaths often go unrecorded.

Personnel of the U.S. Navy and Marine Corps may find themselves stationed or visiting in many parts of the world, particularly the countries bordering the oceans. In some of these countries, snakebite is a significant public health hazard.

VENOMOUS SNAKES

First if there is any doubt that the animal is a snake and a venomous one , or if the family of the snake is unknown then key to the families of snakes should be consulted.

If practicable every medical unit that enters an area where snakebite is a hazard should build up an identified collection of local venomous and nonvenomous snakes. Small individuals or just the heads of large snakes should be sufficient. Such collections are often essential for rapid identification of dangerous species.

If the specimen cannot be  identified readily, it may be:

1. An aberrant individual or one from an atypical population.
2. An uncommon species listed in the regional table but not described in detail.
3. An unknown species or one not previously known from that geographic region;       

A harmless species incorrectly identified as venomous In examining an unidentified snake look first at the head. In all pil vipers (family Crotalidae) there is a deep hollow between the eye and nostril and slightly below a line connecting The two (see Figure 2), The impression is one of an extra nostril, (A large pit viper, Bothrops atrox, is known in Mexico as cuatro narices or fout nostrils.) These pits are actually sensitive heat receptors. They absolutely identify a snake as a pil viper, since they are not seen in any other type of snake. However, some pythons and boas do have pits on the upper lip. The pits may be difficult to recognize for they camouflaged by the head markings so that they are not visible except by close inspection; this offers another reason for bringing the intact snake in for identification. are often camouflaged by the head markings so that they are not visible except by close inspection. This offers another reason for bringing the intact snake in for identification.

DISTINGUISHING FEATURES IN IDENTIFICATION

VENOM APPARATUS

Fangs and venom glands are the only anatomic features that set venomous snakes apart from nonvenomous ones. Caution is demanded in examining the mouth of a freshly killed anake; the biting reflex may porsist in a sovered head for as long as 45 minutes.

HEAD SHIELDS

The size and arrangement of shields on the top and sides of the head are most helpful in snake identification. In the great majority of snakes

 the top of the head is covered by large symmetrical shields, typically 9 in number More or less division of these shields into small scales is seen in many kinds of vipers, many boas and pythons, and in a few other kinds of snakes. Reduction of the mumber through fusion of shields is seen mostly in small burrowing snakes.

EYE CHARACTERISTICS

The shape of the pupil of the eye should be noted in live or freshly  killed snakes. Most snakes have round pupils, some have vertically elliptical pupils, and a few have horizontally elliptical pupils. Vertically elliptical pupils are characteristic of most vipers but some nonvenomous snakes also have this type. Most venomous elapids have round pupils

NON VENOMOUS SNAKES

A recent Gallup poll survey found that more than half of the population (51%) is afraid of snakes (aphidinphobia). The reason for this fear may include many factors. Two possible explanations include

a) everyone can recognize a snake, and

b) they have dured to fear them. People often fear what they don't know.

INTRODUCTION TO REPTILES

The word reptile comes from the word reptar, which means to many or slither. The term describes animals that move slowly with their body near the ground. The study of reptiles is known as herpetology, which also includes amphibians such as frogs and newts. There are over 6500 different kinds of reptiles. Reptiles have four major characteristics as:

All reptiles:

• have a backbone
• produce eggs
• have scales or scutes
• are ectothermic (cold-blooded)

Most reptiles have four legs, except for snakes and some lizards. The physical features of non- venomous, native (indigenous) snakes in North America will be considered. The snakes worldwide live near the tropies.

CHARACTERISTICS

By definition, a snake is a limblers, elongated reptile that is closely related to lizards. All snakes are carnivorous animals, and many species produce venom, which helps to kill their prey. Being reptiles, they are cold-blooded, lay eggs, and have scales. All snakes are of the suborder Serpentes (from serpent) and distinguished from legless lizards by their lack of eyelids and external ears. They breathe air with lungs and have skin made up of specialized dry scales or bony plates/scutes (or both). And, they lay leathery eggs on dry land.There are approximately 3,500 species of snakes worldwide, of which only about 600 are venomous. About 50 species of snakes are found in the United States. Alaska and Hawaii are the only states that do not have snakes.Snakes are easily divided into two groups: venomous and non-venomous. Of that number, 21 snake species in the US are renomons, meaning they produce a neurotoxin that affects the bitten victim's nervous system. So, less than half of the snakes in the US are dangerous to humans. Here, we will consider the non-venomous snakes. Nevertheless, in order to do so, we must be able to identify what snakes are venomous and which are not.Two-headed snakes do not survive long in the wild. These were adopted and now in captivity.

The most significant problem with identifying snakes with generalized characteristics is they do not always follow the rule for all types of snakes! It is sort of like buying a used car: Buyer beware! Do not carelessly handle just any snake you find in the wild because you have identified it to be a plain and harmless water snake, when in fact, you discover the hard way that it just might be a juvenile water moccasin. The rule of thumb with snakes is: Err on the side of cantion.

CONCLUSION

Each year over 7,000 Americans are bitten by venomous snakes. Fortunately, the chances of dying from being bitten by a venomous snake are none(one in 50 million). The University of Florida Wildlife Johnson Lab assures us that ‘you are nine times more likely too die from being struck by lightning than to die of venomous snake bite .’

However, some essential and general characteristics can be used to identify many snakes.

• long,slender bodies
• rounded heads
• round pupils
• usually swim with body submerged.

REFERENCES

1. R.L KOTPAL(Invertebrates and vertebrates)
2. Dr. V.K AGARWAL 9S. Chand series)
3. Phisiology: Principles of anatomy and phisiology by Tortora
4. Molecular biology of the gene by Watson