Brazilian Wandering Spider
The Brazilian wandering spiders are found in South and Central America. They are called wandering because they hunt on the forest floor during the night and don't sit and wait for prey to get entangled in their webs. In fact, Brazilian wandering spiders don't build webs at all but reside in burrows or under fallen leaves or beneath rocks.
In total, there are eight different Phoneutria species1. Phoneutria is the Latin name for Brazilian Wandering Spider. Of the eight species, five do not live in the Amazon, and the eighth species was found in 2007 (ibid).
The best known Brazilian wandering spider is P. nigriventer. Nigriventer means something like "black-belly" when translating the Latin word into English. The black belly is a characteristic of the Brazilian wandering spider; it can be seen when it raises its forelegs, as they often do to look frightening. It is the best known since it has the most toxic venom of the wandering spiders. Very small doses, a few millions of a gram, can kill small rodents, such as mice.
As said, the Brazilian wandering spider is nocturnal. It is aggressive and raises its two forelegs to anyone that gets too close. It is always ready to fight.
Bite Effects & Venom
Its venom is a cocktail of related toxins. It is hypothesized that the venom affects the victim’s ion channels in their cells2.
1 Martins, R. & Bertani, R. The non-Amazonian species of the Brazilian wandering spiders
of the genus Phoneutria Perty, 1833 (Araneae: Ctenidae), with the description of a new species
ZOOTAXA 1526 pp 1-36 (2007).
Gomez, M.V., Kalapothakis, E., Guatimosim, C., Prado, M.A.M.Phoneutria nigriventer venom: A cocktail of toxins that affect ion channels CELLULAR AND MOLECULAR NEUROBIOLOGY 22(5-6) pp. 579-588 (2002).