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Brazilian Wandering Spider

Ningthoujam Sandhyarani
The Brazilian wandering spider is an aggressive and venomous species, thrives in rainforests. Recorded as the world's deadliest spider. Get familiarized with its facts to avoid accidental bites.
Moderately large in size, the Brazilian wandering spider is the most venomous species of all arachnids. So, do not be under the impression that the bigger the spider, the more threat it poses to humans. In size, the body length of the Brazilian wandering spider measures approximately 0.7-1.9 inches, while its leg span is about 5 inches.
Finding one that is up for sale is less likely. With attributes like being fast, territorial, aggressive, and venomous, this spider is not worthy to rear as a pet. The name 'wandering spider' is coined with reference to the fact that this spider roams the forest at nighttime in search of its food.
Upon sighting a prey, this poisonous spider paralyzes it by envenomation. It is also known by the common names, banana spider and armed spider. 'Banana spider' because it is often spotted hiding on banana plants in the rainforests. Some facts about the Brazilian wandering spider are given.


The Brazilian wandering spider was spotted for the first time in the Amazon rainforests. Later studies found that it inhabits the thick forests of Central and South America.
This spider is grouped under the genus Phoneutria of the family Ctenidae. The genus encompasses eight species, of which this is the most poisonous spider, represented by the scientific name P. nigriventer.


If you already know how to identify a spider, look for the key features for identifying Brazilian wandering spider. When disturbed, this spider adopts a characteristic standing posture to scare away the predators. It stands on its hind legs, putting the front legs in the air and swinging itself back and forth.
Another identifiable character is the fangs, characterized by the growth of scarlet red hair over them. Due to these physical resemblances, it is often confused with members of the Cupiennius genus.


This wandering spider doesn't sit and wait for prey to get trapped in its web. Rather, it hunts in the forest and tall trees during nighttime. Similar to other spiders, the diet of an adult wandering spider consists of crickets and other larger insects. It can devour smaller insects, small lizards, mice, and other crawling creatures.


The venom of this spider contains the neurolysin, PhTx3 (or phoneutria nigriventer toxin-3). It affects the neural tissues, thereby blocking the calcium channel and impairing glutamate function. In humans, this toxin causes loss of muscle control, severe pain, difficulty in breathing, and ultimately, death due to oxygen deprivation.
If the bite is left unattended, death may occur within 25 minutes. In case prompt spider bite treatment with antivenom is received immediately, recovery is achieved within one week.

Bite Incidence

This spider is  recorded as the world's most poisonous spider species. It is believed to cause more human deaths than any other species of spider. As it has a tendency to hide in dark corners during daytime, accidents happen when people disturb this spider and get bitten. However, there is no clear data about the number of fatalities caused by its bite.


According to recent recent researches, the Brazilian wandering spider injects venom in just one-third of its bites. Of the total spider bites recorded, the amount of venom injected is very low in 30 percent cases.
On the other hand, there are other poisonous spiders that inject toxin every time they bite. Thus, the record for the most dangerous spider is not justified truly with the wandering spider. Increased publicity about this spider as the most poisonous species is partly due to its wandering nature.
For hiding places, it sometimes lands on anything that comes in its way, like log piles, between banana fruits, closets, cars, and other dark areas. Also, there are reports suggesting the presence of this spider in between banana bunches that are sold in grocery stores. So, do not underestimate any large spider found amongst banana fruits and plants.