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Bushmasters

Facts about the Bushmaster from the printable Fact Sheet  

Species Description

Bushmasters are one of the largest vipers in the world. They are the longest vipers; while Gabon Vipers and Eastern Diamondback Rattlesnakes are the heaviest vipers in the world. There have been reports of bushmasters measuring up to 14 feet but it is more likely that 12 feet is the maximum length. Bushmasters are sexually dimorphic in size with males reaching larger sizes.

Bushmasters are incredibly beautiful snakes with a pinkish tan, orangish tan, reddish brown or yellowish color with a series of dark markings down the back. Younger snakes usually have a darker ground color and lighter marking on their back relative to adult animals. Overall, there is a great deal of variation in color within and among bushmaster species. However, there are some color differences such as melanocephal; having a very dark head. In addition, bushmasters found in Central America often have wider heads with blunter snouts while bushmasters in the Amazon, especially those in the Guiana Shield have a narrower lancehead shape to the head. The middorsal scales or scales that run down the middle of the back have raised knoblike keels. The keels get smaller as you go towards the tail. Bushmaster's fangs can be over 2 inches long and rival the Gabon Viper for longest fang length in snakes.

Taxonomy

The bushmaster was first described by F. M. Daudin in 1803 and the genus name came from one of the Three Fates in Greek Mythology. Lachesis is a goddess that measures the thread of life or how long each person will live. Historically, the genus was thought to be a single species, muta, with four subspecies but subsequent morphological and genetic studies show that there are four species (acrochorda, melanocephala, muta, and stenophrys) with one of the species containing two subspecies (muta muta and muta rhombeata).

Distribution

Bushmasters occur entirely within the New World and specifically within the countries of Bolivia, Brazil, Columbia, Costa Rica, Ecuador, French Guiana, Guyana, Nicaragua, Panama, Peru, Surinam, and Venezuela. The Chocoan Bushmaster (Lachesis acrochorda) occurs on both the Pacific and Atlantic versants of eastern Panama, throughout the valleys of Northwestern Columbia and along the Pacific Coast of Northwest Ecuador. The Black-headed Bushmaster (Lachesis melanocephala) is restricted to the Pacific versant of Costa Rica in the vicinity of the Osa Peninsula. The South America Bushmaster (Lachesis muta) occurs throughout the Amazon Basin and in the coastal Atlantic Forests of Brazil. The Central American Bushmaster (Lachesis stenophrys) occurs in Atlantic lowlands from Nicaragua to Panama. The Black-headed and Chocoan Bushmasters have been found up to 1,600 meters (5,249 feet) in elevation while the South and Central American species have only been found up to 1,000 meters (3,281 feet) in elevation.

Habitat

Throughout their range bushmasters are primarily found in undisturbed lowland and pre-montane rainforest. However, in some parts of their range they can be found in dryer regions but always along riparian corridors. Bushmasters can occasionally be found in forests that have been cut for a short time period but they are mostly associated with primary forest.

Movement and Home Range

Almost nothing is known about the movements and home range size of bushmasters except that they are active primarily at night and that they can remain coiled in the same location for almost a month. Bushmasters have also been observed in seasonally flooded forests during the dry season indicating that they may have some form of seasonal migration to uplan forests during the wet season.

Diet

Bushmasters are sit and wait predators that specialize in eating small mammals including rodents and marsupials. They have also been observed to feed on porcupines. Unlike many other vipers that strike and release their prey, bushmasters often strike and hold onto the prey injecting large amounts venom. Juvenile bushmasters have brightly colored tail tips but unlike other vipers with similar tails they have not been observed using their tail to lure prey.

Reproduction

Bushmaster reproduction is fascinating as they are the only species of vipers in the New World that lay eggs. Females have been observed laying between 6 and 20 eggs in old logs or mammal burrows from May through August. The females then protect the nest by coiling around the eggs which can take approximately three months to hatch. There is some evidence that bushmaster eggs need high humidity to successfully hatch and that nesting may correspond with wet seasons.

Literature Cited



Bushmaster Conservation

Photographs of Bushmaster Snakes

Bushmasters are one of the greatest icons of the untouched rainforests in Central and South America. With every acre of lowland rainforest that is lost to logging and slash and burn agricultural practices, the Bushmaster is becoming more and more endangered.

When we envision virgin rainforests, we may think about jaguars hunting in the shadows, monkeys feeding in the trees, and scarlet macaws flying overhead. But we also need to think about the world's greatest viper, coiled in the buttress of a large fig tree. Bushmasters are a symbol of rainforest wilderness, and if we can save the Bushmaster we can save many of the wildlife species that live in the untouched rainforest such as jaguars, monkeys, tapirs, and macaws.

Bushmasters are one of the largest vipers in the world, and the only viper in the New World that lays eggs. However, we currently lack much basic understanding of the exact needs of Bushmaster populations that we need to know to be able to save them.

Bushmasters are one of the deadliest snakes in the world yet human bites are rare; Bushmasters prefer to remain still to ambush spiny rats and marsupials along the rainforest floor. The real danger of Bushmasters? Bushmasters in the Atlantic coastal forests of Brazil are close to extinction in the wild, as the forest disappears. We need to prevent this from happening in the last pristine rainforests of Central America.



How we're helping

The Orianne Society is working with Osa Conservation, and Osa Conservation Area (Área de Conservación Osa, Sistema Nacional de Áreas de Conservación) in Costa Rica and La MICA Biological Station in Panama to begin studies that will determine the status of, and understand the ecology of, Black-headed Bushmasters and Central American Bushmasters. In particular, the Black-Headed bushmaster has the smallest geographical range of any Bushmaster and is probably the least-known Bushmaster species. As part of the status assessment we plan intensive surveys and field studies on the snake's ecology, to understand its reliance on untouched forest and to develop conservation strategies. 

In addition, The Orianne Society will work with our partners to initiate local education and outreach programs to increase appreciation of this magnificent snake. We are also working to improve access to emergency health-care for snakebite victims in the region.

Importantly, we are also working on developing additional partnerships that will ultimately lead to conservation efforts of the other species of Bushmasters.