Snake | Description, Facts, & Types | Britannica

Snakes and humans

Snakes are misunderstood and often maligned, primarily out of ignorance about their true nature and position in the natural world. All snakes are predators, but venomous snakes (that is, biting snakes that use their fangs to inject toxins into their victims) have given an inaccurate reputation to the entire group, as most people cannot tell the dangerous from the harmless. Only a small percentage (fewer than 300 species) are venomous, and of those only about half are capable of inflicting a lethal bite. Although snakebite mortality worldwide is estimated at 80,000–140,000 people per year, the majority of deaths occur in Southeast Asia, principally because of poor medical treatment, malnutrition of victims, and a large number of venomous species. Although there are about 8,000 venomous snakebites per year in the United States, the average number of annual fatalities is less than 10 or so per year—fewer than are attributed to bee stings and lightning strikes. In Mexico, 10 times as many people die annually from bee stings as from snakebites.

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Snakes can control the amount of venom they inject and may bite aggressively for food or defensively for protection. Snakes have a limited amount of venom available at any given time and do not want to waste it on nonprey organisms. As a result, about 40 percent of bites suffered by humans are defensive in nature and “dry” (without envenomation). Statistics show that the vast majority of snakebites occur while either catching and handling captive snakes or trying to molest or kill wild ones. In either case, the snake is only defending itself. Rattlesnakes, for example, are venomous, and large ones are quite dangerous owing to the amount of venom they can inject. However, most are shy and retreating, and none will attack a person unmolested. When approached or molested, they will coil up and rattle as a warning to be left alone, striking only as a last resort. Most cases of reputed snake attack are based upon encroachment by a person into the snake’s territory, which makes it feel trapped or cornered, or provocation of a snake during the breeding season.

Even in these scenarios, only two snakes have a reputation as dangerous aggressors: the black mamba (Dendroaspis polylepis) of Africa and the king cobra (Ophiophagus hannah) of Southeast Asia. Nevertheless, snakes are inoffensive under the vast majority of circumstances. People are rarely indifferent about them, generally exhibiting emotions that range from religious awe and superstitious dread to repulsion and uncontrollable fear. It is interesting to note that, although most people profess to fear or hate snakes, one of the most visited areas of any zoo is the snake house—proof that snakes are mysterious and fascinating, even if they are loathed. Given their exquisite colours, patterns, and graceful movements as they crawl, swim, or climb, some snakes can be considered among the most beautiful animals.

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In common parlance, venomous snakes are often referred to as “poisonous snakes.” This phrase is not technically correct, because the term “poisonous” only applies to organisms that unload their toxins when another organism consumes them. Very few snakes are truly poisonous. One of the most common, yet harmless, poisonous snakes in North America is the garter snake (Thamnophis), whose body has the ability to absorb and store the toxins of the newts, salamanders, and other poisonous prey it eats.

Nearly every culture since prehistoric times (including various present-day cultures) has worshipped, revered, or feared snakes. Serpent worship is one of the earliest forms of veneration, with some carvings dating to 10,000 bce. Although Satan is depicted as a serpent in the biblical account of the Creation, snakes are revered by most societies. A vast global compendium of superstitions and mythologies about snakes has sprung up. Many stem from the snakes’ biological peculiarities: their ability to shed their skin is associated with immortality; their ever-open eyes represent omniscience; their propensity for sudden appearance and disappearance allies snakes with magic and ghosts; a phallic resemblance embodies procreative powers; and the ability to kill with a single bite engenders fear of any snakelike creature.

The hides of six snake species (especially pythonss and wart snakes) are commonly bought and sold in the skin trade. The number of rattlesnakes used for their skins is minor in comparison. Hundreds of thousands of live snakes are collected for sale in the international pet trade. Nearly 100,000 ball pythons and 30,000 boa constrictors are imported annually into the United States. The removal of such enormous numbers from the wild threatens the survival of these species, and many snake populations are in decline as a result of capture and habitat destruction. The release of nonnative pet snakes into the wild has also led to the introduction of several invasive species, including the Burmese pythons that have devastated small mammal populations in the Florida Everglades.

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