Bothrops asper
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Common names: terciopelo, barba amarilla, nauyaca,[2] fer-de-lance,[3] (more).
Bothrops asper is a venomous pit viper species found in Central and northern South America.[1] No subspecies are currently recognized.[4]
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[edit] Description
Terciopelos are among the most sexually dimorphic snakes. The two sexes are born the same size, but at the age of 7 to 12 months, females begin to grow faster than males. Males never reach 1.95 m long, while females average perhaps 1.85 m, and the greatest confirmed length is 2.5 m. Females have thick bodies, and big females may weigh 6 kg; heavier ones have been reported. Thus female terciopelos are among the heaviest venomous snakes. They also have heads two or three times as big as males in proportion to their size, and proportionally bigger fangs (typically 2.5 cm) as well.[3]
The color pattern resembles that of B. atrox: diagonal stripes and diamonds of various shades of brown. The underside of the head is pale yellowish. Newborn snakes are brighter in color and males have yellow tail tips.
[edit] Common names
Terciopelo, barba amarilla, fer-de-lance,[3] yellow-jaw tommygoff, Central American lancehead.
The rough scales gave rise to the specific epithet asper ("rough" in Latin) and the Spanish name terciopelo (meaning velvet), which is also used in English.
[edit] Geographic range
Found in the Atlantic lowlands of eastern Mexico and Central America, including Guatamala, Belize, Honduras, Nicaragua Costa Rica and Panama. A disjunct population occurs in southeastern Chiapas (Mexico) and southwestern Guatamala. In northern South America it is found in Colombia and Venezuela. The type locality given is "Obispo, on the Isthmus of Darien" (Panama).[1]
Another source describes the range as northwestern Mexico southward to Ecuador, including Belize, Colombia, Costa Rica, Guatemala, Honduras, Nicaragua, Panama, and its presence is questionable in Venezuela. It is also said that the species can be very common.[3]
[edit] Habitat
It chiefly inhabits tropical rainforest and evergreen forest, but is also occurs in dryer areas of tropical deciduous forest, thorn forest and pine savannah near lakes, rivers and streams.
[edit] Behavior
This species is mostly nocturnal, hiding in leaf litter or among roots during the day. They can strike from a coiled or uncoiled position. They usually flee from danger, but may turn abruptly and strike. During a strike, they may aim to the side of their target and quickly bring their head around to bite from behind.[3]
[edit] Feeding
They eat small animals; a study in Brazil found frogs, mammals, lizards, snakes, centipedes, and birds, in decreasing order.[5]
[edit] Reproduction
Males generally stop eating for a time after the beginning of the reproductive cycle, while females stop after a few months of pregnancy. Mating occurs at different times of year in different areas. Gestation is typically 180 to 240 days, and young are born alive. The average litter is about 30, but litters up to 80 or 100 have been reported. Females need extra food after giving birth. Neonates use their tail tips to lure prey (caudal luring).[3]
[edit] Venom
This species is an important cause of snakebite within its range. Together with Crotalus durissus it is the leading cause of snakebite in Yucatán, Mexico. It is considered the most dangerous snake in Costa Rica, responsible for 46% of all bites and 30% of all hospitalized cases; before 1947 the fatality rate was 7%, but this has since declined to almost 0% (Bolaños, 1984). In the Colombian states of Antioquia and Chocó it causes 50-70% of all snakebites with a sequelae rate of 6% and a fatality rate of 5% (Otero et al., 1992). In the state of Lara, Venezuela, it is responsible for 78% of all envenomations and all snakebite fatalities (Dao-L., 1971). One of the reasons so many people are bitten is because of its association with human habitation and many bites actually occur indoors (Sasa & Vázquez, 2003). Well-known herpetologist Douglas March died after being bitten by this species.[2]
B. asper is irritable, fast-moving and agile. It is also regarded as being more excitable and unpredictable than its cousin, B. atrox, and has a reputation for being aggressive. Its large size and habit of raising its head hich off the ground can result in bites above the knee. It has also been observed to eject venom over a distance of at least 6 feet (1.8 m) in fine jets from the tips of its fangs (Mole, 1924).[2]
Bite symptoms include pain, oozing from the puncture wounds, local swelling that may increase for up to 36 hours, bruising that spreads from the bite site, blisters, numbness, mild fever, headache, bleeding from the nose and gums, hemoptysis, gastrointestinal bleeding, hematuria, hypotension, nausea, vomiting, impaired consciousness and tenderness of the spleen. In untreated cases, local necrosis frequently occurs and may require amputation. In 12 fatal cases the cause of death was septicemia (5), intercranial hemorrhage (3), acute renal failure with hyperkalemia and metabolic acidosis (2) and hemorrhagic shock (1).[2]
Venom yield (dry weight) averages 458 mg with a maximum of 1530 mg (Bolaños, 1984)[2] and an an LD50 in mice of 2.844 mg/kg IP.[3]
[edit] Taxonomy
This species was formerly regarded as a subspecies of B. atrox and is still often confused with it.[3]
[edit] Cited references
- ^ a b c McDiarmid RW, Campbell JA, Touré T. 1999. Snake Species of the World: A Taxonomic and Geographic Reference, vol. 1. Herpetologists' League. 511 pp. ISBN 1-893777-00-6 (series). ISBN 1-893777-01-4 (volume).
- ^ a b c d e Warrell DA. 2004. Snakebites in Central and South America: Epidemiology, Clinical Features, and Clinical Management. In Campbell JA, Lamar WW. 2004. The Venomous Reptiles of the Western Hemisphere. Comstock Publishing Associates, Ithaca and London. 870 pp. 1500 plates. ISBN 0-8014-4141-2.
- ^ a b c d e f g h Captive care of B. asper at VenomousReptiles.org. Accessed 6 November 2006.
- ^ Bothrops asper (TSN 585769). Integrated Taxonomic Information System. Accessed on 6 November 2006.
- ^ Schlesinger V. 2002. Animals and Plants of the Ancient Maya: A Guide. University of Texas Press. 224 pp. ISBN 0-292-77759-0.
[edit] Other references
- Bolaños R. 1984. Serpientes, venenos, y ofidismo en Centroamérica. Editoria Universidad de Costa Rica, San José. 136 pp.
- Dao-L. L. 1971. Emponzoñamiento ofícido en el Estado Lara. Gaceta Medica de Caracas 79: 383-410.
- Otero R, Tobón GS, Fernando Gómez L, Osorio R, Valderrama R, Hoyos D, Urreta JE, Molina S, Arboleda JJ. 1992. Accidente ofídico en Antioquia y Chocó. Aspectos clínicos y epidimiológicos (marzo de 1989-febrero de 1990). Acta Médica Colombiana 17: 229-249.
- Sasa M, Vázquez S. 2003. Snakebite envenomation in Costa Rica: a revision of incidence in the decade 1990-2000. Toxicon 41(1): 19-22.
[edit] External links
- Species Bothrops asper at the EMBL Reptile Database
