Lachesis muta

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Lachesis muta
Lachesis muta muta.jpg
Scientific classification edit
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Family: Viperidae
Genus: Lachesis
L. muta
Binomial name
Lachesis muta
(Linnaeus, 1766)
  • [Crotalus] mutus
    Linnaeus, 1766
  • [Coluber] crotalinus
    Gmelin, 1788
  • Scytale catenatus
    Latreille in Sonnini & Latreille, 1801
  • Scytale ammodytes
    Latreille in Sonnini & Latreille, 1801
  • Coluber Alecto
    Shaw, 1802
  • Lachesis mutus
    Daudin, 1803
  • Lachesis ater
    Daudin, 1803
  • Trigonocephalus ammodytes
    Oppel, 1811
  • [Cophias] crotalinus
    Merrem, 1820
  • Trigonoceph[alus]. crotalinus
    Schinz, 1822
  • Lachesis muta
    — Schinz, 1822
  • Lachesis atra
    — Schinz, 1822
  • Scytale catenata
    — Schinz, 1822
  • Bothrops Surucucu
    Wagler, 1824
  • C[rasedocephalus]. crotalinus
    Gray, 1825
  • Lachesis mutus
    A.M.C. Duméril, Bibron &
    A.H.A. Duméril, 1854
  • Lachesis mutus
    Boulenger, 1896
  • Lachesis muta
    Boettger, 1898
  • Lachesis muta muta
    Taylor, 1951
Common names: Southern American bushmaster, Atlantic bushmaster[2]

Lachesis muta is a venomous pit viper species found in South America (including the island of Trinidad in the Republic of Trinidad and Tobago). Two subspecies are currently recognized, including the nominate subspecies described here.[3]


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 almost 3.65 m (12 feet) long, making this the largest of all vipers and the longest venomous snake in the western hemisphere.[4] Lachesis muta is the third longest venomous snake in the world.[citation needed] Weight in this species is estimated at an average of 3 to 5 kg (6.6 to 11.0 lb), somewhat less than the heaviest rattlesnakes or Bitis vipers, such as gaboon viper, and rhinoceros vipers.[citation needed]

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.[5]

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.[5] Like most New World pit vipers, Lachesis muta exhibits defensive tail vibration behavior in response to potential predatory threats[6]

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.[4]

Common names[edit]

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,[7][8] surucucú in the Amazon Basin (surucucu in large part of Brazil), shushúpe in Peru, and pucarara in northern 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.[9] It is also known as the Atlantic bushmaster.[10]


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.[11]

Distribution and habitat[edit]

Found in South America in the equatorial forests east of the Andes: Colombia, eastern Ecuador, Peru, northern Bolivia, eastern and southern Venezuela, the island of Trinidad in the Republic of Trinidad and Tobago,[8] Guyana, Costa Rica Surinam, French Guiana and much of Brazil. The type locality is "Surinami" (Surinam).[1] It occurs in primary and secondary forests; adjacent fields and cleared areas.[4] In Trinidad it tends to prefer hilly and mountainous regions.[12]


Lachesis muta muta in Ecuador

Some reports suggest that this species produces a large amount of venom that is weak compared to some other vipers.[13] 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.[14]

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[further explanation needed]. He also notes a venom yield of 200–411 mg.[15]


Bushmasters prey primarily on rats and mice.


Subspecies[3] Taxon author[3] Common name Geographic range[1]
Lachesis muta muta (Linnaeus, 1766) South American bushmaster Colombia, eastern Ecuador, Peru, northern Bolivia, eastern and southern Venezuela, Trinidad, Guyana, Surinam, French Guiana and much of northern Brazil, Costa Rica
Lachesis muta rhombeata (Wied-Neuwied, 1824) Atlantic Forest bushmaster Coastal forests of southeastern Brazil (from southern Rio Grande do Norte to Rio de Janeiro).


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).[1]

See also[edit]


  1. ^ a b c d McDiarmid RW, Campbell JA, Touré T (1999). Snake Species of the World: A Taxonomic and Geographic Reference, Volume 1. Washington, District of Columbia: Herpetologists' League. 511 pp. ISBN 1-893777-00-6 (series). ISBN 1-893777-01-4 (volume).
  2. ^ Lang, Kirsty (6 October 2013). "Trying to save the heat-seeking Atlantic bushmaster". BBC News. Retrieved 7 October 2013.
  3. ^ a b c "Lachesis muta". Integrated Taxonomic Information System. Retrieved 25 October 2006.
  4. ^ a b c Mehrtens JM (1987). Living Snakes of the World in Color. New York: Sterling Publishers. 480 pp. ISBN 0-8069-6460-X.
  5. ^ a b United States Navy (1991). Poisonous Snakes of the World. New York: U.S. Government / Dover Publications Inc. 203 pp. ISBN 0-486-26629-X.
  6. ^ 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.
  7. ^ Mendes, John (1986). Cote ce Cote la: Trinidad & Tobago Dictionary. Arima, Trinidad. p. 95.
  8. ^ a b "List of Snakes of Trinidad and Tobago" Archived 2006-08-08 at the Wayback Machine at Republic of Trinidad and Tobago Biodiversity Clearing House Archived 2012-12-21 at Accessed 25 October 2006.
  9. ^ Campbell JA, Lamar WW (2004). In Costa Rica it is commonly known as Mata Buey or Casabel Muda The Venomous Reptiles of the Western Hemisphere. 2 volumes. Ithaca and London: Comstock Publishing Associates. 870 pp. 1,500 plates. ISBN 0-8014-4141-2.
  10. ^ Lang, Kirsty (6 October 2013). "Trying to save the heat-seeking Atlantic bushmaster". BBC News. Retrieved 7 October 2013.
  11. ^ Gotch AF (1986). Reptiles — Their Latin Names Explained. Poole, United Kingdom: Blandford Press. 176 pp. ISBN 0-7137-1704-1.
  12. ^ Herklots GAC (1961). The Birds of Trinidad and Tobago. London: Collins. p. 10.
  13. ^ Lachesis muta, The Silent Fate at South American Pictures. Accessed 26 October 2006.
  14. ^ Ripa D (2001). "Bushmasters and the Heat Strike" at Archived 2008-04-09 at the Wayback Machine. Accessed 26 October 2006.
  15. ^ Brown JH (1973). Toxicology and Pharmacology of Venoms from Poisonous Snakes. Springfield, Illinois: Charles C. Thomas. 184 pp. LCCCN 73-229. ISBN 0-398-02808-7.

Further reading[edit]

  • Bolaños R (1972). "Toxicity of Costa Rican snake venoms for the white mouse". American Jour. Trop. Med. Hyg. 21: 360-363.
  • 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.
  • Linnaeus C (1766). Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio Duodecima, Reformata [Part 1. Twelfth Edition, Revised]. Stockholm: L. Salvius. 532 pp. (Crotalus mutus, new species, p. 373). (in Latin).
  • O'Shea M (2005). Venomous Snakes of the World. Princeton, New Jersey: Princeton University Press. 160 pp. ISBN 0-691-12436-1.
  • 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[edit]