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What the sources say

South American BushmasterLachesis muta

Every figure, record and mechanism on the South American Bushmaster profile was written from a source, and this is the working table behind it: 48 claims checked word for word against these sources. The left column is what the page says. The right column is the source's own words, copied, not paraphrased; a ... marks a cut and[brackets] an insertion. Open any source and check it yourself.

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Source
01

Animal Diversity Web, University of Michigan

Lachesis muta (South American bushmaster). Animal Diversity Web, University of Michigan.

The page saysIts scientific name means "silent fate,"
The source saysThe scientific name Lachesis muta means "silent fate" referring to their tail shaking, though they lack a rattle.
The page saysa nod to the tail it shakes when threatened, though it has no rattle
The source saysLike other vipers, they rattle their tails when threatened, but there are no actual rattles.
The page saysHatchlings emerge at approximately 30 to 50 centimeters long with a bright orange or yellow tail tip used to lure prey, a color that fades as they grow older.
The source saysThe young hatch at approximately 30 to 50 cm with bright orange or yellow tail tips, used to lure prey; this color fades over time.
The page saysNobody knows how long one lives in the wild
The source saysLifespan of wild individuals is unknown.
The page sayswhere it is so secretive that many of its habits are unknown
The source saysMany of their habits are unknown as they are so secretive.
The page saysThe Central American bushmasters were described as subspecies of Lachesis muta, and many now treat them as full species
The source saysAt least three subspecies have been described are now considered full species by many authorsNote: ADW 2012, after the 1994-2003 splits it cites; no quote names L. acrochorda, so it is left out
The page saysthe Central American bushmaster, from southeastern Nicaragua to the Pacific coast of Colombia and Ecuador, and the black-headed bushmaster of southeastern Costa Rica
The source saysLachesis muta stenophrys, the Central American bushmaster, occurs from southeastern Nicaragua to the Pacific coast of Columbia and Ecuador. Lachesis muta melanocephala, black-headed bushmaster, occurs in southeastern Costa Rica
The page saysLachesis muta keeps the rest of the range in South America.
The source saysLachesis muta muta encompasses the remainder of the range in South America.
The page saysdangerLevel: Deadly
The source saysTheir venom attacks the circulatory system and can cause death without treatment.

Source
02

The Online Guide to the Animals of Trinidad and Tobago, University of the West Indies

Lachesis muta (Bushmaster or Mapepire Zanana). The Online Guide to the Animals of Trinidad and Tobago, University of the West Indies.

The page saysThe longest of all vipers
The source saysThis terrestrial snake is the longest of all viperids.Note: UWI (Trinidad guide, c. 2011, after the splits) says this of Lachesis muta itself; the 1997 Toxicon 'world's longest pit viper' and ADW 2012 'second longest venomous snake' lines were broad-sense bushmaster and were cut
The page saysable to aim a strike in the dark by body heat alone
The source saysIf an endothermic (warm-blooded) animal is closer than 50 cm in any direction from the bushmaster, it can detect its heat signature and aim its strike precisely without any other sensory information.Note: 'in the dark': 'Bushmasters hunt at night and are ambush predators'
The page saysfrom the only pit vipers in the Americas that lay eggs
The source saysBushmaster females are oviparous (egg-laying) and are the only oviparous pit vipers in the Western Hemisphere.Note: source's own plural: all bushmasters (the genus) lay eggs, so the rank is not pinned on L. muta alone
The page saysSmall rainforest mammals, especially the rice rat Oryzomys, and sometimes birds
The source saysThe small rice rat, Oryzomys sp., is the bushmaster's favourite in the wild. ... commonly small mammals and sometimes birds up to 120 g
The page saysFacial heat-sensing pits that let it aim a strike at a warm body within 50 centimeters with no other senses needed
The source saysIf an endothermic (warm-blooded) animal is closer than 50 cm in any direction from the bushmaster, it can detect its heat signature and aim its strike precisely without any other sensory information.
The page saysbacked by venom produced in quantities of up to 400 milligrams
The source saysis produced in such large quantities (up to 400 mg) that the prey is dead within minutes
The page saysBy day the South American bushmaster (*Lachesis muta*) rests in a burrow
The source saysThey spend most of the daylight period in their burrows resting until the sun goes down.
The page saysit did not dig, stolen from or shared with an agouti or an armadillo
The source saysThe bushmaster does not make its own home but scouts its environment for burrows made by large rodents such as agouti or armadillos and either steals the burrow for itself or shares it with the other animal.
The page saysit moves infrequently and very slowly
The source saysBushmasters are very cryptic, move infrequently and very slowly
The page saysAdults are usually well over 2.5 meters long and weigh 3 to 5 kilograms
The source saysAdults are usually well over 250 cm and 3-5 kgNote: 250 cm converted to 2.5 m
The page sayssome of the longest reach about 3.5 meters
The source sayswith some of the longest approximately 350 cmNote: 350 cm converted to 3.5 m
The page saysmaking it the longest of all vipers
The source saysThis terrestrial snake is the longest of all viperids.
The page saysA bushmaster hunts at night by ambush
The source saysBushmasters hunt at night and are ambush predators.
The page sayshidden under leaves or dense foliage until prey comes within range
The source saysThey are ambush predators and so lie in the dark waiting, hidden under leaves or in dense foliage until prospective prey comes within strike range.
The page saysA pair of pits between its eyes and nostrils reads infrared heat
The source saysbushmasters have one heat-sensing pit, on each side of their head midway between the nostril and eye
The page saysif a warm body comes within 50 centimeters, the snake can aim its strike from that heat signature alone, with no other senses involved
The source saysIf an endothermic (warm-blooded) animal is closer than 50 cm in any direction from the bushmaster, it can detect its heat signature and aim its strike precisely without any other sensory information.
The page saysIts favorite meal in the wild is the small rice rat.
The source saysThe small rice rat, Oryzomys sp., is the bushmaster's favourite in the wild.
The page saysPrey over 120 grams is usually struck, released and trailed by scent.
The source saysThey usually strike-release then perform chemosensory searching and trail-following if they prey weighs over 120 gNote: 'trailed by scent' for 'chemosensory searching and trail-following'
The page saysIts venom is relatively weak next to its close relatives', but it comes in volume
The source saysIts venom, though relatively weak to closely related species, is produced in such large quantities
The page saysup to 400 milligrams, one of the largest amounts produced by any snake
The source saysis produced in such large quantities (up to 400 mg) that the prey is dead within minutes. This is one of the largest volumes of venom produced by any species of snake.
The page saysenough that even released prey usually dies within minutes
The source saysEven if the prey gets away because of its size, the venom will usually kill it within minutes.
The page saysThe Egg-Laying Exception
The source saysBushmaster females are oviparous (egg-laying) and are the only oviparous pit vipers in the Western Hemisphere.
The page saysBushmasters are the only pit vipers in the Western Hemisphere that lay eggs.
The source saysBushmaster females are oviparous (egg-laying) and are the only oviparous pit vipers in the Western Hemisphere.
The page saysA female lays 8 to 12 white eggs, each a little larger than a chicken egg, coils her body around the clutch, and does not leave it for any reason until the eggs hatch roughly 78 days later.
The source saysShe lays eight to twelve white eggs, a little larger than a chicken egg. After laying, she wraps her body around them and protects them until approximately 78 days later when they hatch ... She does not leave her eggs for any reason during this period.Note: eight to twelve spelled out as 8 to 12
The page saysA bushmaster lies hidden under leaves until prey comes within strike range
The source saysThey are ambush predators and so lie in the dark waiting, hidden under leaves or in dense foliage until prospective prey comes within strike range.
The page saysa warm body closer than 50 centimeters is enough to aim by heat alone
The source saysIf an endothermic (warm-blooded) animal is closer than 50 cm in any direction from the bushmaster, it can detect its heat signature and aim its strike precisely without any other sensory information.
The page saysweightKg: 4
The source saysAdults are usually well over 250 cm and 3-5 kgNote: 4 kg is the midpoint of the 3 to 5 kg adult range; every value in it is the Light class

Source
03

AnAge: The Animal Ageing and Longevity Database

AnAge entry for Lachesis muta. AnAge: The Animal Ageing and Longevity Database.

The page saysThe longest-lived on record reached 31.6 years in captivity.
The source saysMaximum longevity 31.6 years (captivity)Note: AnAge Build 15 (2023) supersedes ADW's 2012 captive record of 24 years; 'longest-lived on record' restates 'Maximum longevity'
The page saysThe longest-lived on record reached 31.6 years in captivity.
The source saysMaximum longevity 31.6 years (captivity)Note: FAQ copy of the body's lifespan claim; FAQ ref is AnAge, which states the figure; 'longest-lived on record' restates 'Maximum longevity'

Source
04

Gutiérrez-Cárdenas et al. 2021

Gutiérrez-Cárdenas et al. (2021). Lachesis muta. The IUCN Red List of Threatened Species 2021: e.T62254A44946798.

The page saysLeast Concern
The source saysIUCN Red List category: Least Concern (LC).Note: read through GBIF's copy of the Red List, since iucnredlist.org refuses scripts (docs/fact-check.md); assessment DOI dated 2021, after ADW 2012's 'Vulnerable'
The page saysthe IUCN lists the species as Least Concern
The source saysIUCN Red List category: Least Concern (LC).Note: read through GBIF's copy of the Red List; assessment DOI dated 2021

Source
05

Pinho & Pereira 2001

Pinho & Pereira (2001). Ofidismo. Revista da Associação Médica Brasileira.

The page saysRainforest across the Amazon and Atlantic Forest, with pockets of humid forest in northeastern Brazil
The source saysHabitam áreas florestais como Amazônia, Mata Atlântica e alguns enclaves de matas úmidas do NordesteNote: translated from Portuguese: 'They inhabit forest areas like the Amazon, the Atlantic Forest and some humid forest enclaves of the Northeast'
The page saysA 2001 Brazilian medical review notes that most of the country's snakebites come from lanceheads and rattlesnakes, and that bites by Lachesis are rare.
The source saysA maioria destes acidentes deve-se a serpentes do gênero Bothrops (jararaca, jararacuçu, urutu e outros) e Crotalus (cascavel), sendo raros os produzidos por LachesisNote: translated from Portuguese: 'Most of these accidents are due to snakes of the genus Bothrops (jararaca, jararacuçu, urutu and others) and Crotalus (rattlesnake), those produced by Lachesis being rare'; 'lanceheads' is the standard English name for Bothrops; 2001 is the review's publication year (reference year); 'most' translates 'A maioria'
The page saysTheir systemic effects can include low blood pressure, dizziness, darkened vision, a slowed heartbeat, abdominal cramps and diarrhea, grouped as a "vagal syndrome."
The source saysAs manifestações sistêmicas incluem hipotensão arterial, tonturas, escurecimento da visão, bradicardia, cólicas abdominais e diarréia ("síndrome vagal")Note: translated from Portuguese: 'Systemic manifestations include low blood pressure, dizziness, darkening of vision, bradycardia, abdominal cramps and diarrhea ("vagal syndrome")'; scoped to the Brazilian review
The page saysThe bushmaster lives in forest across the Amazon and the Atlantic Forest, with pockets of humid forest in Brazil's northeast
The source saysHabitam áreas florestais como Amazônia, Mata Atlântica e alguns enclaves de matas úmidas do NordesteNote: translated from Portuguese, same passage as the stats.habitat claim
The page saysIn the national figures for 1990 to 1993, Lachesis caused 1.4 percent of the snakebites whose snake genus was recorded, against 90.5 percent for Bothrops lanceheads and 7.7 percent for rattlesnakes.
The source saysno período de 1990 a 1993 ocorreram 81.611 acidentes ... Dentre os casos em que o gênero da serpente foi informado, Bothrops foi responsável por 90,5% dos casos, Crotalus por 7,7%, Lachesis por 1,4%Note: translated from Portuguese: 'in the period 1990 to 1993 there were 81,611 accidents ... Among the cases where the snake's genus was reported, Bothrops was responsible for 90.5% of cases, Crotalus 7.7%, Lachesis 1.4%'; decimal commas converted

Source
06

Junqueira-de-Azevedo et al. 2006

Junqueira-de-Azevedo et al. (2006). Lachesis muta (Viperidae) cDNAs Reveal Diverging Pit Viper Molecules and Scaffolds Typical of Cobra (Elapidae) Venoms: Implications for Snake Toxin Repertoire Evolution. Genetics.

The page saysA Viper's Venom with Cobra Parts
The source saysan ohanin-like toxin, which would be the third member of the most recently described class of Elapidae toxinsNote: the paper's title calls these 'Scaffolds Typical of Cobra (Elapidae) Venoms'
The page saysGeneticists sequencing bushmaster venom genes found atypical molecules "never observed in the hundreds of Viperidae snakes studied so far,"
The source saysatypical molecules never observed in the hundreds of Viperidae snakes studied so far are highly expressedNote: 'venom genes' for the paper's cDNAs of possible toxins
The page saysincluding one from a class of toxins described from Elapidae, the snake family that includes cobras and mambas
The source saysan ohanin-like toxin, which would be the third member of the most recently described class of Elapidae toxinsNote: 'the snake family that includes cobras and mambas' identifies Elapidae for readers; standard taxonomy

How the table was made: a writer drafted the profile from these sources and logged each claim with its quote, a reviewer with nothing but this table checked every sentence said no more than its quote, and a script confirmed each quote appears word for word in the source. The method is in the site'sAbout page.