Use Caution in Brazil

Thursday, January 30, 2025

Use Caution in Brazil

Today’s special animal friend is the Brazilian Wandering Spider, Phoneutria nigriventer. *evil laugh* This large, highly-venomous spider is one of several in its genus. Native to South America, this genus includes some of the world’s largest spiders. They have a body length of up to two inches and a legspan of up to six inches. They are also heavy, as spiders go.

The individual shown in that video is not full size. It also didn’t bite the guy. The wandering spider is not aggressive. It is defensive. The specimen in the video did not feel threatened, so it just wandered around his arm and then wandered off. When a wandering spider feels threatened, it will rear up and wave its front legs defensively. If the threat persists, the spider may try a non-venomous bite. They can do this at will, which is fantastic. The use of their venom is a last resort.

That guy was trying to provoke the spider. Wandering spiders are nocturnal ambush predators. Like many spiders, they will eat just about anything that is smaller: insects, other spiders, scorpions, reptiles and amphibians. They will not eat poisonous animals such as poison dart frogs or toxic moths.

That video is pretty overwrought. However, the venom of the wandering spider is very dangerous. It can cause several symptoms such as priapism, tachycardia, arrhythmias, cardiogenic shock, acute pulmonary edema and convulsions. The venom contains at least six neurotoxic peptides, which produce extreme pain and inflammation in addition to the outcomes above.

As usual with spiders, females are bigger than males, and the males can be snacked by their mates. In spite of this, the males will dance – it is Brazil – and even fight one another for access to females. The female will produce, when she gets around to it, about one thousand eggs per season.

In Brazil, you can find wandering spiders in your house, especially during the dry season when males are looking for females. Be careful. IUCN has not evaluated the status of Brazilian wandering spiders. They have some natural predators including coatis and other insectivorous mammals.