List of dangerous snakes

It is a polypeptide analogous to the human atrial natriuretic peptide; it is responsible for causing diuresis through natriuresis and dilating the vessel bloodstream, which results in, among other things, acceleration of venom distribution in the body of the victim, thereby increasing tissue permeability.

[40][41] These advanced and highly evolved physical and biological features combined with this species' large size, explosive aggression, and quickness make the black mamba a terrifying adversary.

A polyvalent antivenom produced by the South African Institute for Medical Research (SAIMR) is used to treat all black mamba bites from different localities.

It inflates and compresses its body laterally (not dorso-ventrally like many other species) and may also spread the back of its jaws to give the head a broader, lance-shaped appearance.

The muscular lightweight body of the Taipan allows it to hurl itself forwards or sideways and reach high off the ground, and such is the speed of the attack that a person may be bitten several times before realizing the snake is there.

[47] The venom affects the nervous system and the blood's ability to clot, and bite victims may experience headache, nausea and vomiting, collapse, convulsions (especially in children), paralysis, internal bleeding, myolysis (destruction of muscle tissue) and kidney damage.

Of the 166 bite victims, 139 (84%) showed clinical evidence of envenoming: local signs were trivial, but the majority developed hemostatic disorders and neurotoxicity.

Specific antivenom raised against Australian taipan venom was effective in stopping spontaneous systemic bleeding and restoring blood coagulability but, in most cases, it neither reversed nor prevented the evolution of paralysis even when given within a few hours of the bite.

[57] However, because it ranges from Pakistan, India (in rocky regions of Maharashtra, Rajasthan, Uttar Pradesh and Punjab), Sri Lanka, parts of the Middle East and Africa north of the equator,[64] is believed to cause more human fatalities every year than any other snake species.

[74] In most of the local encounters with live, wild king cobras, the snakes appear to be of rather placid disposition, and they usually end up being killed or subdued with hardly any histrionics.

These support the view that wild king cobras generally have a mild temperament, and despite their frequent occurrence in disturbed and built-up areas, are adept at avoiding humans.

Naturalist Michael Wilmer Forbes Tweedie felt that "this notion is based on the general tendency to dramatise all attributes of snakes with little regard for the truth about them.

A moment’s reflection shows that this must be so, for the species is not uncommon, even in populated areas, and consciously or unconsciously, people must encounter king cobras quite frequently.

[88] The SC LD50 value is 0.4 mg/kg[89] and the venom yield per bite can range anywhere from 70–236 mg.[90] Unlike other snakes that flee from approaching humans crashing through the undergrowth, common death adders are more likely to sit tight and risk being stepped on, making them more dangerous to the unwary bushwalker.

An adult woman bitten by this species in northwestern Pakistan suffered severe neurotoxicity and died while en route to the closest hospital nearly 50 minutes after envenomation.

[111] Deaths from respiratory failure have been reported, but most victims will survive if prompt administration of antivenom is undertaken as soon as clinical signs of envenomation have been noted.

Bites by the Philippine cobra produce a distinctive clinical picture characterized by severe neurotoxicity of rapid onset and minimal local tissue damage.

[69] It is the best-known venomous snake in the wealthy and heavily populated areas of southeastern Brazil, where it was responsible for 52% (3,446 cases) of snakebites between 1902 and 1945, with a 0.7% mortality rate (25 deaths).

The major toxic components in the Monocled cobras venom are postsynaptic neurotoxins, which block the nerve transmission by binding specifically to the nicotinic acetylcholine receptor, leading to flaccid paralysis and even death by respiratory failure.

[143] According to Ernst & Zug et al. the murine SC LD50 value is 0.21 mg/kg,[109] making it one of the most venomous true cobra species (genus Naja) in the world.

A case report in the literature describes pain and irritation of the eyes, bilateral redness, excessive tear production and whitish discharge, with superficial corneal opacity but normal acuity.

Average venom yield is 80–120 mg and the murine LD50 is 1.1–1.6 mg/kg SC with an estimated lethal dose for humans of 50–60 mg. Actual bites from this species are fairly rare, and deaths in modern times are so far unheard of.

Based on the degree and type of local effect, bites can be divided into two symptomatic categories: those with little or no surface extravasation, and those with hemorrhages evident as ecchymosis, bleeding and swelling.

[clarification needed] Deaths are rare and occur in less than 10% of all untreated cases (usually in 2–4 days from complications following blood volume deficit and a disseminated intravascular coagulopathy), although some reports show that very severe envenomations have a 52% mortality rate.

Weinstein and Smith (1990) list a venom yield of 10 mg.[176] Humans are rarely bitten by the tiger rattlesnake, and literature available on bites by this snake is scarce.

[174][176] The neotropical rattlesnake or cascavel (Crotalus durissus) is a medically important species due to its venom toxicity and the human fatalities it is responsible for.

[178] While the lethal dose for a 60 kg adult human is 18 mg.[118] The neotropical rattlesnake in Brazil is of special importance because of the high incidence of envenoming and mortality rates.

[179] The huge area of distribution, potent venom in fairly large quantities and a definite willingness to defend themselves are important factors in their dangerousness.

The most common subspecies of Mojave rattlesnake (type A) has venom that is considered to be one of the most debilitating and potentially deadly of all North American snakes, although chances for survival are very good if medical attention is sought as soon as possible after a bite.

[citation needed] The timber rattlesnake, (Crotalus horridus),[192] is a species of venomous pit viper endemic to eastern North America.