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https://en.wikipedia.org/wiki/List_of_dangerous_snakes#Mojave_rattlesnake
Mojave rattlesnake[edit]
The Mojave rattlesnake (Crotalus scutulatus) is another species which is considered to be dangerous. Although they have a reputation for being aggressive towards people, such behavior is not described in the scientific literature. Like other rattlesnakes, they will defend themselves vigorously when disturbed. The IP LD50 value is 0.18 mg/kg with an average venom yield between 50–150 mg per bite. 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.[186] Based on median LD50 values in lab mice, venom A from subspecies A Mojave rattlesnakes is more than ten times as toxic as venom B, from type B Mohave green rattlesnakes which lacks Mojave toxin.[187]
Medical treatment as soon as possible after a bite is critical to a positive outcome, dramatically increasing chances for survival.[186] However, venom B causes pronounced proteolytic and hemorrhagic effects, similar to the bites of other rattlesnake species; these effects are significantly reduced or absent from bites by venom A snakes.[188] Risk to life and limb is still significant, as with all rattlesnakes, if not treated as soon as possible after a bite. All rattlesnake venoms are complex cocktails of enzymes and other proteins that vary greatly in composition and effects, not only between species, but also between geographic populations within the same species. The Mojave rattlesnake is widely regarded as producing one of the most toxic snake venoms in the New World, based on LD50 studies in laboratory mice.[189] Their potent venom is the result of a presynaptic neurotoxin composed of two distinct peptide subunits.[190] The basic subunit (a phospholipase A2) is mildly toxic and apparently rather common in North American rattlesnake venoms.[191] The less common acidic subunit is not toxic by itself, but in combination with the basic subunit, produces the potent neurotoxin called "Mojave toxin". Nearly identical neurotoxins have been discovered in five North American rattlesnake species besides the Mojave rattlesnake.[191] However, not all populations express both subunits. The venom of many Mojave rattlesnakes from south-central Arizona lacks the acidic subunit and has been designated "venom B," while Mojave rattlesnakes tested from all other areas express both subunits and have been designated "venom A" populations.[192]
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