The Amazon rainforest is the largest tropical rainforest in the world, covering the majority of the northern part of South America and extending into Peru, Colombia, Brazil, Ecuador, Bolivia, Venezuela and the three Guyanas. With millions of animal species competing in a highly populated and fiercely competitive environment, animals have adapted various characteristics for defence and attack. The poisonous animals in the Amazon rainforest secrete harmful, often lethal, venoms to attack prey and to defend from predators.
Poison Dart Frogs
Numerous species of poison dart frogs may be found throughout the Amazon. These frogs are relatively small, ranging from 1/2 inch to 2 inches in length, and exhibit among species a wide variety of colourful neon patterns. Their bright colouring is a warning sign to predators of their poisonous nature. The poison from these frogs is usually excreted through the skin and is not naturally produced but, rather, is a result of the poison dart frog's particular diet of insects. Phyllobates aurotaenia, Phyllobates bicolor and Phyllobates terribilis--the most poisonous of these frogs--have been used by native Colombian tribes to poison the tips of their darts; hence, the origin of this frog family name.
Brazilian Wandering Spider
The Brazilian wandering spider gets the first part of its name from its origin of discovery in Brazil; however, the spider also has been found in other parts of Amazonia as well as Central America. The "wandering" title represents its hunter tendencies, sweeping the jungle floor for prey rather than waiting in a web like most spiders. The highly aggressive spider has a large, hairy body with a leg span that may reach up to 5 inches and large, bright red fangs that secrete an extremely powerful venom. While it preys principally on insects, small reptiles and rodents, the Brazilian wandering spider's venom may be lethal to humans; indeed, these spiders are reported to have bitten more humans than has any other spider species.
Two principle families of venomous snakes that may be found throughout Amazonia are vipers and elapids.
Vipers are characterised by hinged fangs, which are long and retractable, as well as a large body with a short tail and a triangular-shaped head. One of the most common vipers in the Amazon is the bushmaster, also known as "surucucu" in Brazil, where it is commonly found. This is an extremely venomous, nocturnal snake with a body that averages between 6 feet and 7 feet long.
Elapids are often slender and diurnal, characterised by fixed fangs that remain permanently erect. The himeralli is a well-known elapid found in Guyana, with a heavy body and strong swimming capabilities. This snake's venom incorporates neurotoxins that cause respiratory paralysis and eventually suffocation.