page_title: List of dangerous snakes
section_title: South American bushmaster
hierarchical_section_title: List of dangerous snakes / Considerably dangerous / South American bushmaster
caption_attribution_description: Lachesis muta muta (bushmaster)
context_page_description: Of the 3,500 snake species, there are around 600 venomous snake species in the world. This is an overview of the snakes that pose a significant health risk to humans, through snakebites or other physical trauma.
  The varieties of snakes that most often cause serious snakebites depend on the region of the world. In Africa, the most dangerous species include black mambas, puff adders, and carpet vipers. In the Middle East the species of greatest concern are carpet vipers and elapids; in Central and South America, Bothrops and Crotalus are of greatest concern. In South Asia, it has historically been believed that Indian cobras, common kraits, Russell's viper and carpet vipers were the most dangerous species; however other snakes may also cause significant problems in this area of the world. While several species of snakes may cause more bodily destruction than others, any of these venomous snakes are still very capable of causing human fatalities should a bite go untreated, regardless of their venom capabilities or behavioral tendencies.
context_section_description: The South American bushmaster (Lachesis muta muta) is the longest species of venomous snake in the Western Hemisphere and the longest pit viper in the world. It is native to parts of South America, especially the equatorial forests east of the Andes. They are active at dusk or after dark and so they are very secretive and elusive. This species is large, fast and has a reputation for being particularly aggressive when cornered. Some reports suggest that this species produces a large amount of venom that is weak compared to some other vipers. Others, however, suggest that such conclusions may not be accurate. These animals are badly affected by stress and rarely live long in captivity. This makes it difficult to obtain venom in useful quantities and good condition for study purposes. For example, Bolaños (1972) observed that venom yield from his specimens fell from 233 mg to 64 mg while they remained in his care. As the stress of being milked regularly has this effect on venom yield, it is reasoned that it may also affect venom toxicity. This may explain the disparity described by Hardy and Haad (1998) between the low laboratory toxicity of the venom and the high mortality rate of bite victims. However, wild specimens have an average venom yield per bite of 280–450 mg (dry weight) (U.S. Dept. Navy, 1968). According to (Sanchez et al., 1992), who used wild specimens from Pará, Brazil, the average venom yield per bite was 324 mg, with a range of 168–552 mg (dry weight). Brown (1973) gives the following LD₅₀ values for mice: 1.5 mg/kg IV, 1.6–6.2 mg/kg IP, 6.0 mg/kg SC. He also notes a venom yield of 200–411 mg. Human envenoming by this species, although infrequent, can be rather severe due to the large volumes of venom injected. Envenomation is characterized by pronounced local tissue damage and systemic dysfunctions, including massive internal bleeding.
caption: South American bushmaster (Lachesis muta muta)
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