Inland taipan
Belcher's sea snake ("Hydrophis belcheri"), which many times is mistakenly called the hook-nosed sea snake ("Enhydrina schistosa"), has been erroneously popularized as the most venomous snake in the world, due to Ernst and Zug's published book "Snakes in Question: The Smithsonian Answer Book" from 1996. Bryan Grieg Fry, a prominent venom expert, has clarified the error: "The hook-nosed myth was due to a fundamental error in a book called "Snakes in Question". In there, all the toxicity testing results were lumped in together, regardless of the mode of testing (e.g. subcutaneous vs. intramuscular vs intravenous vs intraperitoneal). As the mode can influence the relative number, venoms can only be compared within a mode. Otherwise, it's apples and rocks." Belcher's sea snake's actual LD (recorded only intramuscularly) is 0.24 mg/kg and 0.155 mg/kg, less lethal than other sea snakes such as the olive sea snake ("Aipysurus laevis") 0.09 mg/kg and the most toxic intramuscularly, recorded of the sea snakes – the black-banded robust sea snake ("Hydrophis melanosoma") 0.082 mg/kg. The black-banded robust sea snake has also been tested subcutaneously registering at 0.111 mg/kg. more than four times less toxic than the inland taipan's venom. In the LD subcutaneous test, it is actually Dubois' sea snake ("Aipysurus duboisii") which has the most toxic venom of any of the sea snakes tested, registering at 0.044 mg/kg. This is still nearly half as lethal as the inland taipan's venom.
List of dangerous snakes
The Neotropical rattlesnake or Cascabel ("Crotalus durissus") is a medically important species due to its venom toxicity and the human fatalities it is responsible for. The IP value is 0.17 mg/kg with an average venom yield between 20–100 mg/kg per bite. Bite symptoms are very different from those of Nearctic species due to the presence of neurotoxins (crotoxin and crotamine) that cause progressive paralysis. Bites from "C. d. terrificus" in particular can result in impaired vision or complete blindness, auditory disorders, ptosis, paralysis of the peripheral muscles, especially of the neck, which becomes so limp as to appear broken, and eventually life-threatening respiratory paralysis. The ocular disturbances, which according to Alvaro (1939) occur in some 60% of "C. d. terrificus" cases, are sometimes followed by permanent blindness. Phospholipase A neurotoxins also cause damage to skeletal muscles and possibly the heart, causing general aches, pain, and tenderness throughout the body. Myoglobin released into the blood results in dark urine. Other serious complications may result from systemic disorders (incoagulable blood and general spontaneous bleeding), hypotension, and shock. Hemorrhagins may be present in the venom, but any corresponding effects are completely overshadowed by the startling and serious neurotoxic symptoms. Subcutaneous venom for this species is 0.193 mg/kg. The neotropical rattlesnake in Brazil is of special importance because of the high incidence of envenoming and mortality rates. Clinically, venom of this snake does not usually cause local effects at the bite site and is usually painless. However, the etiology progresses to systemic neurotoxic and myalgic symptoms, with frequent renal failure accompanied by acute tubular necrosis. The huge area of distribution, potent venom in fairly large quantities and a definite willingness to defend themselves are important factors in their dangerousness. In Brazil and probably also in other countries in their area of distribution, this species is probably the most dangerous rattlesnake. After the fer-de-lance ("Bothrops asper"), it is the most common cause of snake envenoming. In the first half of the 20th century as well as in the 1950s and 1960s, 12% of treated cases ended fatally. Untreated cases apparently had a mortality rate of 72% in the same period, but this was due to the fact that there was no antivenom, poor medical care and neglect (Rosenfeld, 1971). In more recent times, an average of 20,000 snakebites are registered each year in Brazil, almost 10% of them caused by the neotropical rattlesnake. The mortality rate is estimated at 3.3% and is thus much lower than in the past (Ribeiro, 1990b). A study from southeastern Brazil documented only one fatality from 87 treated cases (Silveira and Nishioka, 1992).