As rainforests are so rich in biodiversity with the presence of favourable conditions such as warmth and water, it is no surprise that snakes in general are found in their greatest numbers in the tropical areas of the Earth. (Ref. 1)
We’ve even encountered a mention of the fact that “…most large amphibians and reptiles are today exclusively tropical in distribution”. (Ref. 2)
As a significant part of the wildlife of tropical forests around the world, snakes have an impact on other animals both as predators and prey.
Out of around 2,700 species of snakes in the world, only 1/5 th are venomous; the rest are not. (Ref. 4)
Without trying to put an exact figure on it, we would assume that rainforests house a similar proportion of venomous and non-venomous snakes.
Snakes use most types of habitats in a rainforest – most of them live on and under the ground but some of them also inhabit trees and water sources. (Ref. 5)
Rainforest snakes are carnivores. They employ several ways of attacking other animals. Non-venomous snakes can either pin their prey to the ground or “constrict” them which means that they wrap their own bodies around them in a coil and squeeze them until the victim dies. Venomous snakes normally inject venom into their prey. (Ref. 6)
Boas (such as anacondas, boa constrictors and pythons) are probably some of the most popular rainforest snakes.
The Amazon forest – the largest tropical rainforest of the world – is home to a great variety of snakes.
As some authors mention: “… snakes appear to be the single most diverse reptile group in the Amazon Basin, where more than 175 snake species have been described”. (Ref. 7)
The floodplains house a large number of all the reptile species found in the Amazon Basin, and though many species of snakes inhabiting the Amazonian floodplains are aquatic the majority of them are most likely arboreal. Many Amazonian snakes, such as boas, pit vipers and some colubrids, move to live in the forest’s trees during floods. (Ref. 8)
We have read many stories about an amazing ability of snakes (such as green anacondas, for example) to swallow other animals of truly astounding dimensions.
This is possible thanks to the unique physical construction of a snake’s body. Paul Cutright has given us its excellent description which we are quoting below:
“The structure of the hard palate and the relationship of the lower jaw to the upper one are responsible for the unparalleled swallowing feats of which snakes are capable. The hard palate is not rigid in snakes as it is in mammals, … … the lower jawbones, of which there are two instead of one as in higher forms, are loosely attached to the cranium by elastic connections. In practically all vertebrates the lower jaw is firmly anchored to the upper, and no amount of pulling will sever the connection; as a result the size of the throat, or pharynx, is limited, and only small morsels may be swallowed.
The loose connections in snakes, on the contrary, permit the lower jaw to be pulled away from the upper, so that the size of the object engulfed sometimes reaches perfectly astounding proportions. The existence of two lower jawbones, connected in the chin region only by elastic ligaments, is also of advantage in increasing the size of the oral and pharyngeal cavities. Moreover it facilitates to a great extent the swallowing process, for snakes ingest their food by a process which may be called "jaw-walking."
Each half of the lower jaw works independently. After the teeth of the snake have taken a firm grip on the animal--the head end is invariably engulfed first--one half of the lower jaw, the right side, for instance, is advanced a slight distance and then takes a new purchase while the left side holds and, at the same time, exerts a strong pull. The next step is for the right side to pull while the left advances for a new hold. In this manner the body of the intended victim is slowly but surely "walked" into the gullet of the serpent.
Snakes probably swallow other snakes more rapidly than they do any other animals. Fouror five-foot snakes have been known to swallow others of their kind only slightly inferior in size within less than ten minutes. While engaged in ingestion serpents can quickly disgorge all that has been swallowed if they are bothered or frightened. Frequently the entire animal has been swallowed and then regurgitated.” (Ref. 9)
Many species of rainforest snakes currently face a number of threats to their existence, just like other rainforest animals.
We should try to protect snakes as part of a concerted effort to conserve animals in the wild.
Written by: Irina Bright of Tropical-Rainforest-Animals.com
Publication Date: September 2007