Bothrops asper

Aug 16, 2020 Interesting Creatures in Guyana, News

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Bothrops asper (common names Terciopelo [English], Cuatro Narices [Spanish], and often called the fer-de-lance among many other colloquial names) is a venomous pit viper species, ranging in distribution from southern Mexico to northern South America. They are found in a wide range of lowland habitats, often near human habitations. Because of its proximity to human habitations and its defensive temperament, it is more dangerous to people than many other snakes. This species is the main cause of snakebite incidents within its range. No subspecies are currently recognized.
Bothrops species can be distinguished by their broad, flattened heads which are set apart from the rest of their bodies. The head of this snake is light to dark brown or even black. Although usually absent, it may have occipital blotches or streaks that range from indistinct to distinct. The underside is most often pale yellow. This species has different patterns and colours on its dorsal and ventral sides and it exhibits a postorbital stripe. The ventral side is yellow, cream, or a whitish grey, with dark blotches that are more frequent closer to the posterior end. Ventrolaterally, B. asper has interchanging grey scales which are more pale towards the medial line. Dark triangles with pale edges can be seen laterally, which range in number from 18 to 25. Apices either alternate or are reflective of each other over the middorsal line. In the interspaces, there are dark, paravertebral blotches. Specimens may have a yellow zig-zag-shaped line on each side of the body. There is a great variety of colours on its dorsal side: olive, grey, light brown to dark brown, tan or sometimes nearly black. To prevent water loss where they occur in drier regions, this species has more scales.
Specimens of this species may weigh up to 6 kilograms (13 lb) and are often 1.2 to 1.8 meters (3.9 to 5.9 ft) in length. Very big females can reach lengths up to 2.5 metres (8.2 ft), although this is uncommon. These are among the most sexually dimorphic of all snakes. The two sexes are born the same size, but by age 7 to 12 months, females begin to grow at a much faster rate than males. Females have thick, heavy bodies and grow significantly larger than males. They also have heads two or three times the size of males relative to their size and proportionally bigger fangs (typically 2.5 cm), as well.
Across its geographic range, this species varies greatly phenotypically. As a result, great confusion between it and other related species, most notably Bothrops atrox, which is similar in colour but usually has yellow or rust-like tones and rectangular or trapezoidal blotches.
It is found on the Gulf – Atlantic versant of eastern Mexico as far north as the state of Tamaulipas, southward into Central America, including Guatemala, Belize, Honduras, Nicaragua, Costa Rica and Panama. An isolated population occurs in southeastern Chiapas (Mexico) and southwestern Guatemala. In northern South America, it is found in Colombia, Ecuador, Guyana and Venezuela. The type locality given is “Obispo, on the Isthmus of Darien” (Panama).
This is mostly a lowland species that, in Mexico and Central America, occurs from about sea level to 1,200 to 1,300 meters (3,900 to 4,300 ft) altitude. In South America, it apparently ranges to considerably higher elevations: up to 2,500 metres (8,200 ft) in Venezuela and at least 2,640 metres (8,660 ft) in Colombia according to herpetologist Lancini.
According to Campbell and Lamar (2004), its range in Ecuador extends as far south along the Pacific coast as El Oro Province and the Vilcabamba area of the Río Catamayo Valley. This species is reported to occur from seven (Bolívar, Carchi, Chimborazo, Esmeraldas, Guayas, Los Ríos and Pichincha) of the fourteen provinces along the Pacific slope of Ecuador. There are even a few records from northern coastal Peru, with these snakes being reported in the Tumbes Region. It is also known from the island of Gorgona off the Pacific coast of Colombia.
B. asper occurs throughout the inter-Andes valleys of Colombia across the Caribbean coastal plain through central Venezuela north of the Orinoco as far east as the Delta Amacuro region. This is the only Bothrops species that occurs on the island of Trinidad, although the situation there is complicated due to proximity of Trinidad to the Orinoco Delta where it may be sympatric with B. atrox.
Due to the casual and informal application of the name “Fer-de-lance” being applied to any number of species of Latin America pit vipers in the genus Bothrops, there is much confusion and misunderstanding, particularly in popular literature, as to proper nomenclature. Populations of Bothrops often referred to as Fer-de-lance on the island of Saint Lucia are Bothrops caribbaeus. Populations of Bothrops referred to as Fer-de-lance on the island of Martinique are regard as Bothrops lanceolatus. (Source: Wikipedia)