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By Anders Nielsen, Ph.d.
Each year, 8,000 bites from venomous snake species are reported in the USA. On average, only five of these bites lead to death (Gold et al., 2002)1. The total number of snake bites is close to 45,000 (Litovitz et al., 1997)2, which means that around 18 percent of all bites in the U.S. are from venomous species.
According to statistics, the copperhead snake is responsible for most venomous snake bites.
Worldwide, India is the country most affected by venomous snake bites, with around 35,000 to 50,000 yearly fatalities due to snake bites, and Pakistan comes second with approximately 8,200 fatalities (Alirol et al., 2010)3.
Snakes can consume prey significantly wider than their own diameter. The phenomenon that allows them to do so is commonly referred to as jaw-walking.
Snakes’ jaws attach only loosely to their skulls, and unconnected, they can work independently. That is, the two sides can collaborate on pulling the animal inward.
By alternating the two actions, keeping a grip and pulling, swallowing large animals is possible; having elastic skin is a prerequisite.
The biggest concern from snake bites, including the non-venomous ones, is infections at the site of the bite. That is also the case with any pets that might have been bitten without you knowing it. You just observe that one of its limbs seem sore. If you take a pet to the veterinarian because of a bite, they will probably only treat it with antibiotics and painkillers. There are only a few venomous snakes that will actually be able to kill an animal as large as a dog: such as the timber rattlesnakes or the diamondback rattlesnakes;not copperhead snakes.
As the camera crew repeatedly annoys the cobra, the cobra begins to growl. The cobra was found in a paddy field in India. The cobra snake is large, and the camera men are taking an enormous risk trying to relocate it. The main risk is when they put into the bag. The cobra must be released without giving it the chance to bite.
The different species of snakes have their fangs curving in three dissimilar but typical patterns. Ducts inside the fangs connect the fangs to the venom glands, the red areas on the photos, where the production of venom takes place.
Skull from an elapid snake.
Skull from a viperid snake.
Skull from a rear-fanged snake.
Injuries caused by venomous snakes are rare. When compared to the number of people killed by lightning, which in 1959-1994 was 0.42 people per million (Curran et al., 1994)4, snake envenomations suddenly seem insignificant.
Sutherland (1992)5 studied Australian snake bite fatalities over a ten-year period. Only 18 snake bites had a deadly outcome in that period. The author acknowledged that all fatalities may not be included in the available set of data.
Puff adders, as one reader noted, are the snakes responsible for most fatalities in Africa. Add the cape cobra to that list too. This site also describes the boomslang (a very Afrikaans word), the gaboon viper, and the black mamba.
In South and Central America, bites from venomous snakes are more common than in the U.S. In Costa Rica, the annual number of hospital admissions due to snake envenomations is 22.4 per 100,000 inhabitants (Rojas et al., 1997)6.
Swallowing animals would be difficult without teeth. Snakes’ teeth are curved, and they help to pull the animal farther into the mouth. The image shows a jaw from a diamondback rattlesnake, and it is taken from an exhibition at the American Museum of Natural History. Larger snakes have longer teeth as they often have to penetrate feathers to kill prey their own size. The diamondback rattlesnake on the photo from the museum has rather short teeth.
This story is a good illustration on why you have to be careful even when just taking a photo of a venomous snake. This guy took photo of a diamondback rattlesnake and tries to pin its head with a stick that is too short. It lashes out and bites him. To begin with, the pain is nothing, but soon the venom is about to paralyze him. Twenty minutes later he is barely able to get out of his kayak. He manages to get into his car, and eventually he reaches a hospital where he gets 26 doses of antivenom.
Snakes serve an important role as predators in ecosystems, and healthy ecosystems are often abundant in a variety of predators, such as snakes, that maintain populations of rodents and other animals at acceptable levels. Just think of farmers and the problems they have with rodents. Snakes are actually responsible for keeping crop yields high and for preventing the spreading of diseases.
Jackie Bibby beat his old world record by holding 13 rattlesnakes in his mouth at the same time without being bitten. Mr. Bibby already has the world record in sleeping with most rattlesnakes at the same time in a sleeping back (109) and being in a bathtub with most rattlesnakes at the same time (195). Congratulations.
In the Thrane district of India (West Bengal) a sharp increase in fatalities from snake bites has been reported. However, the true number of deaths is much larger than official numbers imply as many people are not even registered as snake bite victims. Also, many people don't even make it to the hospital before they die.
Recently, a group of scientists from North Carolina (NCSU) found that female copperheads and cottonmouth snakes are capable of reproducing asexually. That is, no male is needed for fertilizing an egg. From a litter of copperhead they found one parthenogenic snake from a litter of 22 copperheads. From a litter of 37 cottonmouth snakes they also found that one was parthenogenic. Although parthenogenesis has been seen before in snakes held in captivity, the finding is important to our understanding of vertebrate evolution. Read more about the study at www.venomoussnakes.net
1 Gold, BS et al. ("Bites of Venomous Snakes". New England Journal of Medicine Vol. 347, No. 5 pp. 347-356 (2002)
2 Litovitz TL et al. ("Annual report of the American Association of Poison Control Centers Toxic Exposure Surveillance System" Am J. Emerg Medicine 15, pp. 447-501 (1997)
3 Alirol et al."Snake Bite in South Asia: A Review", PLOS NEGLECTED TROPICAL DISEASES, Vol. 4(1) pp. 1-7 (2010)
4 Curran EB. et al. "Lightning injuries and Damage Reports in the United States from 1959-1994" (1997), NOAA Technical Memo-randum
5 Sutherland SK "Fatalities from Snake Bite in Australia, 1981-1991", MED. JOURNAL OF AUSTRALIA 157 Vol. 11-12. pp. 740-746 (1992)
6 Rojas G et al. "Snakebite mortality in Costa Rica", Toxicon, Vol. 35 pp. 1639-43 (1997)
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