The Brazilian wandering spider is highly venomous and particularly aggressive. The 2007 Guinness World Records reports this spider as the most venomous in the world, although species such as the black widow are responsible for many more deaths. That said, a single spider was responsible for the deaths of two children in São Sebastião, according to a study by Wolfgang Bucheral published in "Venomous Animals and their Venoms, Vol. III."
There are more than 900 species of tarantulas in the Amazon rainforest. These large, hairy spiders are impressive to look at, but they are not dangerous to humans, except those who have a strong allergic reaction. The largest tarantula, found in northern Brazil and Venezuela, is the Goliath brdeater, Theraphosa blondi. It is the second largest spider in the world, weighing in at 6 ounces with a leg span of 12 inches. It was given its name by some Victorian explorers who saw one eating a hummingbird.
More than 500 species of jumping spiders occupy the canopies of the Amazon rainforest. As the name suggests, they are able to navigate their leafy habitat by jumping, secured by a silk tether. They rely on good eyesight for this locomotive technique, something they are also able to use when hunting.
Jumping spiders tiny in size, measuring from 3-5mm in length, and harmless to humans, although they are known for their 'curiosity', and will investigate an outstretched hand rather than flee from it (Global Species Database).
