Many snake species, from all over the world, are currently listed as threatened or endangered. Many of these snakes are on the brink of extinction. Currently, there are several hundred snake species listed on the International Union for Conservation of Nature's (IUCN) Red List of Threatened Species. Furthermore, According to David Badger (Voyageur Press 2002), forty years ago herpetologist Archie Carr warned that "snakes are probably disappearing at a more rapidly rising rate than any other group of vertebrates.''
A variety of human-created issues have caused snakes to disappear. Below is an outline of the threats that snakes face.
One of the biggest issues affecting snakes is the loss of their natural habitat (i.e their homes). Many areas that were once suitable for snakes to live have now been destroyed. Habitats of all kinds are being lost at an alarming rate. Wetlands are drained, forests are cut down, and waterfronts are developed. Snakes are literally losing their homes and they are losing them rapidly.
Remaining natural habitats are often degraded and fragmented. Fragmentation occurs when healthy areas of habitat are isolated from one another. Snake populations are affected since gene flow between populations is prevented. Habitat fragmentation is also harmful because it often eliminates crucial requirements of the area which are critical to the survival of snake populations. Such areas include spaces that can be utilized for thermoregulation, prey capture, mating, and hibernation. Without such habitat requirements, populations will dwindle. Habitat complexity is extremely important as it offers shelter to snakes from both predators and human persecution. Another important feature within snake habitats is gestation sites. These are areas where gravid females congregate to easily access shelter and places to aid thermoregulation. Snakes will often use the same sites year after year, so the loss of such areas in the form of habitat destruction can negatively affect the entire population and its reproductive output.
Degradation occurs when the natural habitat has been altered and degraded to such a degree that it is unlikely that any remaining snake species would be able to survive. Contaminants and sewage runoff from developmental construction and human settlement further cause harm to snakes and their increasingly degraded habitats. Pesticides, oils, chemicals, and industrial pollution contaminate the habitats of snakes and their local prey. When the snakes consume contaminated prey, they may become poisoned and die. Habitat destruction and degradation can also affect the availability of prey items, causing unnatural declines in inappropriate food sources.
Snake habitats are also often subjected to human-induced alterations. The introduction of erosion netting or similar netting materials such as nylon netting, plastic bird netting, chicken wire, glue traps, and garden traps can all pose serious risks to snakes. These reptiles often end up trapped, seriously injured or even killed as a result of being entangled inside such materials. Similar incidences can arise when snakes become trapped in twine, discarded netting, and fishing lines.
Habitat loss presents a huge problem for snakes that experience cold weather conditions. When temperatures become too low for snakes to remain active, they retreat to dens known as hibernacula. These dens go well below the frost line and provide a winter sanctuary for the snakes. Large congregations of snakes, sometimes of varying species, use the same dens year after year. When dens are destroyed through construction and developments, the snakes are left without a winter refuge and perish.
Habitat loss puts snakes in greater danger of encounters with humans. Once their natural habitat has been destroyed, snakes are forced (by no fault of their own) into urbanized environments. Here they are likely to be killed by fearful humans, or those who deem them as pests.
Habitats are often isolated and cut off from one another by the roads and highways that now run through them. Countless numbers of snakes are killed on roads and highways every year when they are hit by vehicles. Snakes that are moving to breed, egg-laying, or den sites must often cross over roads to reach such areas. Here many of the mature members of the breeding population are killed. Removing members of the breeding populations greatly limits the reproductive output, and this makes it incredibly hard for snake numbers to rebound. Gravid (pregnant) females that get hit, who carrying eggs or internal young are especially tragic as not only are these mature snakes killed, but the next generation of snakes is killed off too!
In many cases, people will purposely swerve to run over and kill snakes. Snakes are attracted to roads because the sun-baked surface provides an opportunity to absorb heat.
Roads present an additional problem for snakes because they represent a form of habitat loss. The roads that run through natural areas also fragment the existing populations, drastically making them smaller in size. This limits the gene flow and genetic diversity between the isolated populations on either side and this greatly increases the chances of extirpation (i.e local populations becoming extinct). When snakes must cross roads to travel between the populations, it greatly increases their chances of being hit and killed by vehicles.
One of the most significant threats to wild snake populations today is the change in the climate. According to Chris Mattison's The New Encyclopedia of Snakes (2007, Chris Mattison), concerns about habitat destruction, which were arguably uppermost in the thoughts of most conservationists in the 1980s and 1990s, have been supplemented, or eclipsed, with concerns over global climate change. Some scientists predict that up to one-third of the earth's species may become extinct in the next century. Many of these will be snakes, lost as a result of desertification, rising sea levels, and increasing pressure on land that will be required to feed and house a burgeoning human population in a period of diminishing resources.
Climate change is the suspected cause of the widespread disappearance of many snake species and the decline in their populations, even within an intact natural habitat.
While human activities have negative impacts on snakes, they have helped increase the number of snake predators. The increase in human waste has provided an unlimited food source for predators like skunks and raccoons. This has caused the number of these predators to increase significantly, and this surplus of predators takes its toll on snake populations.
Harvesting & Poaching
Every year literally millions of snakes are harvested directly from the wild for various trades. Snakes are captured for their skins, for the trinket trade, and for food.
Numerous other snakes are killed so parts of their bodies can be utilized and then sold off. For example. Rattlesnake heads and rattles are used to make keychains. Rattlesnakes are also killed and made into paperweights, belt buckles, and numerous other items. The fangs from snakes are sometimes used to make earrings. The list of products that contain parts of snakes is seemingly endless.
According to Animal Welfare Advocate, Ashley Fruno, each year around the world, millions of crocodiles, lizards, and snakes are subjected to abuse and killed for their skins. National Geographic reports that more than 24 million reptile parts were exported from Southeast Asia alone between 2000 and 2007! Reptile skins are used for handbags, purses, belts, shoes, boots, wristbands, clothes, and more.
According to Dr. Clifford Warwick, a specialist in reptile biology and welfare, almost all snakes used for the skin trade are wild-caught. He went on to say that "Snakes are never killed in a good way. They are decapitated and eviscerated. I'm quite sure that the use of snakeskin by fashion houses is threatening the sustainability, the durability, and the sheer number and safety of snakes in the wild."
Large numbers of snakes are killed for food every year. Restaurants offering various snake dishes are popular throughout Asia. Snakes are also killed for alcoholic beverages. According to David Allen (2001), the body of a snake or several snakes is left to steep in a jar or container of liquor. It is claimed that this makes the liquor stronger (as well as more expensive). One example of this is the Habu snake (Protobothrops flavoviridis), which is sometimes placed in the Okinawan liquor. This is known as "Habu Sake." The consumption of snakes is not restricted to Asian countries alone. Rattlesnake meat is widely consumed and sold across the Midwestern United States.
Many traditional Chinese medicines involve the use of snake meat, organs, or blood. These practices represent yet another realm in which snakes are used and killed. The fats and oils from snakes, typically the Chinese Water Snake (Enhydris chinensis) and certain species of rattlesnakes (Crotalus species), are used in Chinese and traditional medicines to treat joint pain, despite alternatives being available.
Snakes are often used as "props" or gimmicks in movies and television shows. Here they may be subjected to any form of misuse, especially to elicit a defensive response (to appear ''scary'' for the cameras). This includes rattlesnakes rattling, hissing, or hooding.
The general portrayal of snakes in the media is detrimental to these animals. Snakes are usually portrayed as aggressive and malicious creatures. This reputation only promotes fear of these animals and this fear helps fuel unjust and widespread persecution.
Snake charmers and "sideshow'' handlers also exploit snakes for monetary gain. The snakes that are used in such acts are often taken from their natural habitats. Many snake charmers and snake handlers do not give their animals the proper care they need to remain healthy. In fact, many handlers subject their snakes to terribly cruel and inhumane conditions. This includes having the snake's venom ducts punctured with hot needles. This incapacitates the animal's ability to deliver venom. The handlers will also pull out the snake's fangs or sew their mouths shut as a way of avoiding bites. These actions cause the snakes extreme pain and suffering. It also leads to premature death. This means new snakes will have to be obtained for use in the side-shows and these replacement snakes will be subjected to the same cruelty.
Similarly to sea turtles, sea snakes fall victim to being trapped inside nets, trawls, and lines that are intended to catch other prey. Estimates from the Northern Prawn Fishery indicate that in 1991 alone between 30,000 and 67,000 sea snakes were killed as a result of commercial prawn trawling. However, this estimate contains figures from just one fishery, globally the number of sea snakes that are killed as a result of incidental catch would be significantly higher. According to the Great Barrier Reef Marine Park Authority female, sea snakes are caught more often than males, and that mature snakes are caught more often than juveniles. This is especially disturbing as mature females are crucial to the reproductive output of the population. The loss of mature breeding capable individuals can have devastating effects on the entire population.
Snakes are often the victims of deliberate killings by fearful people. According to Seburn and Seburn (2000) snakes are feared and persecuted by humans more than any other group of animals and humans are the greatest threat to most species of snakes.
Many snake species live in areas where they will become inactive (hibernate) for many parts of the year. Due to this inactivity, and the relatively short time to feed and reach an adequate and healthy weight, breeding females may only produce young once every two or three years. In some areas, as much as two-thirds of the breeding population will not reproduce young. This means that the direct killing of any gravid females can have serious effects on the decline of the entire population. This makes the persecution of snakes from humans a very serious threat.
An example of the destructive impact that intentional killings can have on snake populations can be clearly seen in the case of the Timber Rattlesnake (Crotalus horridus), which once occurred in Southern Ontario.
Timber Rattlesnakes use to be found in the Niagara gorge area of the province, however, deliberate killings of the snakes, often in the form of bounty hunting, commercial collecting and sport hunting at communal overwintering dens quickly exterminated the entire population. The last sighting of a Timber Rattlesnake in Ontario was in 1941. The snake is now listed as extirpated (a species that is extinct or completely exterminated in one area but occurring elsewhere in the world) from Canada.
The most extreme example of people directly killing snakes are the annual rattlesnake roundups that are held across the United States. The snakes used in these roundups are captured from their natural habitat. In many cases, gasoline is poured into dens to force out the snakes. During the roundups, the snakes are subjected to torture, including being kicked, stomped on, whipped, burned, and skinned. Snakes are then killed by decapitation. False information on snakebites is given out at roundups to inspire fear and the justification of the animal cruelty and disregard of life that is carried out.