Lachesis muta, also known as the Southern American bushmaster or Atlantic bushmaster,
Taxonomy
Two additional subspecies,
L. m. melanocephala and
L. m. stenophrys, had earlier been recognized. However, both were elevated to species level by Zamudio and Green in 1997 (see
L. melanocephala and
L. stenophrys).
Subspecies
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| Lachesis muta muta | (Carl Linnaeus, 1766) | South American bushmaster | Southeastern Colombia, eastern Ecuador, Peru, northern Bolivia, eastern and southern Venezuela, Trinidad, Guyana, Suriname, French Guiana and much of northern Brazil |
| Lachesis muta rhombeata | (Wied-Neuwied, 1824) | Atlantic Forest bushmaster | Coastal forests of southeastern Brazil (from southern Rio Grande do Norte to Rio de Janeiro). |
|
Description
Adults grow to an average of 2 to 2.5 m (6½-8 feet), although 3 m (10 feet) is not too unusual. The largest recorded specimen was 3.65 m (almost 12 feet) long, making the species the largest of all
Viperidae and the longest venomous snake in the Western Hemisphere.
[Mehrtens JM (1987). Living Snakes of the World in Color. New York: Sterling Publishers. 480 pp. .] Lachesis muta is the third longest venomous snake in the world, exceeded in length only by the
king cobra and the
black mamba. Weight in this species is estimated at an average of , somewhat less than the heaviest
(like the eastern diamondback rattlesnake) or
Bitis vipers (such as the
Gaboon viper and
rhinoceros viper).
The head is broad and distinct from the narrow neck. The snout is broadly rounded. There is no canthus. A pair of small internasals is present, separated by small scales. The supraoculars are narrow. Other parts of the crown are covered with very small scales. Laterally, the second supralabial forms the anterior border of the loreal pit, while the third is very large. The eye is separated from the supralabials by 4-5 rows of small scales.[United States Navy (1991). Poisonous Snakes of the World. New York: U.S. Government / Dover Publications Inc. 203 pp. .]
The body is cylindrical, tapered and moderately stout. Midbody there are 31-37 nonoblique rows of dorsal scales which are heavily keeled with bulbous tubercles and feebly imbricate. There are 200-230 ventral scales. The tail is short with 32-50 mainly paired subcaudals, followed by 13-17 rows of small spines and a terminal spine.[Allf, B. C., Durst, P. A., & Pfennig, D. W. (2016). Behavioral plasticity and the origins of novelty: the evolution of the rattlesnake rattle. The American Naturalist, 188(4), 475-483.]
The color pattern consists of a yellowish, reddish or grey-brown ground color, overlaid with a series of dark brown or black dorsal blotches that form lateral inverted triangles of the same color. The lateral pattern may be precisely or indistinctly defined, normally pale at the center.
Venom
Some reports suggest that this species produces a large amount of venom that is weak compared to some other vipers.
[ Lachesis muta, The Silent Fate at South American Pictures. Accessed 26 October 2006.] Others, however, suggest that such conclusions are not 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.
[Ripa D (2001). "Bushmasters and the Heat Strike" at VenomousReptiles.org . Accessed 26 October 2006.]
Brown (1973) gives the following values for mice: 1.5 mg/kg Intravenous, 1.6–6.2 mg/kg Peritoneum, 6.0 mg/kg SC. He also notes a venom yield of 200–411 mg.[Brown JH (1973). Toxicology and Pharmacology of Venoms from Poisonous Snakes. Springfield, Illinois: Charles C. Thomas. 184 pp. LCCCN 73-229. .] The bushmaster's venom has proteolytic activity, which destroys and causes lesions in the tissue, anti-coagulant, which causes incoagulable blood, hemorrhagic and neurotoxic, that acts mainly on vagal stimulation. The symptoms are quite similar to those caused by Bothrops, at the site of the bite there is pain, edema, ecchymosis, skin necrosis, , vesicles and blisters. The main complications at the bite site include necrosis, compartment syndrome, secondary infections and functional deficit. The systemic effects are characterized by hypotension, dizziness, visual disturbances, bradycardia, abdominal pain, nausea, vomiting and diarrhea.
Etymology
Lachesis is one of the three Fates in
Greek mythology and was supposed to assign to man his term of life—something this species is certainly capable of doing. The species is similar in appearance to
rattlesnakes and vibrates its tail vigorously when alarmed, but has no rattle and was therefore called
mutus (later
muta), which is Latin for "dumb" or "mute". However, when in the undergrowth, the tail actually makes quite a loud rustling noise.
[Gotch AF (1986). Reptiles — Their Latin Names Explained. Poole, United Kingdom: Blandford Press. 176 pp. .]
Common names
Known as the
mapepire zanana or
mapepire grande (pronounced
ma-pa(y)-PEE za-Na-na or
ma-pa(Y)-PEE GRAN-dey) in Trinidad,
[Mendes, John (1986). Cote ce Cote la: Trinidad & Tobago Dictionary. Arima, Trinidad. p. 95.][ "List of Snakes of Trinidad and Tobago" at Republic of Trinidad and Tobago Biodiversity Clearing House . Accessed 25 October 2006.] surucucú in the
Amazon Basin (
surucucu in a large part of Brazil),
shushúpe in Peru, and
pucarara in Bolivia. In Venezuela the species is known as
cuaima or
cuaima piña. In Colombia it is known as
verrugosa or
verrugoso due to the warty look of its scales, and in Suriname as
makasneki and
makkaslang.
[Campbell JA, Lamar WW (2004).]
It is called ĩtsãi in the Kwaza language of Rondônia, Brazil.[Manso, Laura Vicuña Pereira. 2013. Dicionário da língua Kwazá. M.A. dissertation. Guajará-Mirim: Federal University of Rondônia.]
In the Shawi language of Peru, it is called na’shi.[Rojas-Berscia, Luis Miguel. 2019. From Kawapanan to Shawi: Topics in language variation and change. Doctoral dissertation, Radboud University Nijmegen.]
Distribution and habitat
L. muta is found in South America in the equatorial forests east of the
Andes, and the island of Trinidad.
The type locality is "Surinami" (Suriname).
It occurs in primary and secondary forests; adjacent fields and cleared areas.
In Trinidad it tends to prefer hilly and mountainous regions.
[Herklots GAC (1961). The Birds of Trinidad and Tobago. London: Collins. p. 10.]
Diet
Bushmasters prey primarily on rats and mice. Birds and reptiles may occasionally be eaten.
Proechimys are favored prey items in Costa Rica.
and
are other favored prey.
Other prey items include porcupines, squirrels, opossums, squirrel monkeys, and frogs.
Further reading
-
Bolaños R (1972). "Toxicity of Costa Rican snake venoms for the white mouse". American Jour. Trop. Med. Hyg. 21: 360–363.
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Hardy DL Sr, Haad JJS (1998). "A review of venom toxinology and epidemiology of envenoming of the bushmaster ( Lachesis) with report of a fatal bite". Bull. Chicago Herp. Soc. 33(6): 113–123.
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Carl Linnaeus (1766). Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio Duodecima, Reformata Part. Stockholm: L. Salvius. 532 pp. ( Crotalus mutus, new species, p. 373). (in Latin).
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O'Shea M (2005). Venomous Snakes of the World. Princeton, New Jersey: Princeton University Press. 160 pp. .
-
Zamudio KR, Greene HW (1997). "Phylogeography of the bushmaster ( Lachesis muta: Viperidae): implications for neotropical biogeography, systematics and conservation". Biological Journal of the Linnean Society 62: 421–442. PDF at Cornell University, Department of Ecology and Evolutionary Biology. Accessed 26 October 2006.
External links
