Boidae Family:

It is integrated in our country by four sorts:

Boa, Epicrates, Eunectes and Corallus

The Island of Madagascar extends by Tropical America and. It is represented by great snakes, with previous but much long mandibular teeth maxilars and that the later ones; somewhat triangular head, of canine aspect and cover of very small scales. The body strong and is laterally compressed; the tail is short, pointed and prehensile. The Boas are nocturnal

This family includes the biggest snakes of the world. They are not venomous, but some species can be dangerous by their big and powerful muscle These snakes have maxilars bones, palatal and pterigoides movable; supratemporary bone present. Maxilares, mandibular and coronoides bones have teeth. They own vestiges of pelvis and, sometimes, in the later members has form of claws or spurs, located to each one of the sides of the anal opening. It is distributed by the south-east of Europe, Africa, Asia, Australia and America

It includes/understands around 100 species.

According to Lancini

Includes the largest snakes of the continent, reaching up to 5 or 6 meters in length, of preferably tree habits. The differentiation of the cephalic scales are minimum; rostral, the nasals, mental and also supra and infralabial. The mandibular teeth maxilars and are previously greater but they are decreasing gradually backwards; the pupil is vertical; there is absence of fosetas labial; the cephalics scales are small and irregular. Reduced spurs are observed, relics of the lost later members, around the sewage opening. A single species exists in the continent and some small islands of the Antilles; its subdivision in subspecies still does not appear well defined. In the subtropical and temperate regions of Argentina and in Paraguay, Boa constrictor occidentalis is solely; apparently it is replaced in Missions by the Brazilian subspecies, Boa constrictor constrictor, and the third subspecies, Boa constrictor amarali, would be to the Southeast of Bolivia and southwest of Brazil, but he would not be present in our country.

Origin:

The snakes appeared about 120 Million years. The family of the Boids, in which belong the boas, anacondas and pythons, is one of the oldest families of snakes that exists. In the prehistoric world, the animal had to be great and strong to survive, and the venon still did not exist; for that reason the family of the Boids constituted one of the greates snakes that exists. These snakes come from the lizards, proof of it is the prongs or cornículo to each side of the anal region (but developed in the males and used for the reproduction). This represents the last vestiges of the later extremities that disappeared during the evolution. 

All the serpents that belong to this sort are of Aglifa set of teeth which means that they lack venomous glands. but still is not animal inoffensive they have an incredible muscular force method with which they kill to his prey of the asphyxia method and devour them whole, cases have been listened to in which big snakes like the Anacondas and Boas have killed people, but are not but exaggerations with exceptions of very particular cases in indians populations.

References:

Kornacker, P. M. 1999. Checklist and key to the snakes of Venezuela / Lista sistemática y clave para las serpientes de Venezuela. PaKo-Verlag. 270 pp.

Lancini, A. R. 1979. Serpientes de Venezuela. Armitano Editores. 262 pp.

Lancini, A. R. y P.M. Kornacker. 1989. Die Schlagen von Venezuela. Armitano Editores. 381 pp.

Navarrete, L. F., J. C. López Johnston y A. Blanco Dávila. (s/f) 2006. Guía de las Serpientes de Venezuela Biología, venenos, conservación y checklist. Gráficas Lauki. 75 pp.