Like that of the Banana Spider, the venom produced by the North American Black Widow also acts on the nervous system. Deaths are caused by its victims being unable to breath. While Banana Spiders are aggressive, Black Widows only bite in self defence, for example if they are accidentally trodden on. Although their venom is extremely potent, deaths in healthy adults are extremely rare and anti-venom treatment is usually successful.
Although the Brown Huntsman Spider also appears fearsome, it is easily scared by humans and will flee on their approach. It has great speed and agility, running out of its hiding place of small cracks to ambush its prey, as although it has the ability to produce silk it does not spin webs. They are common in Australia, and their leg span can be up to 20cm! They are often regarded as welcome inhabitants of homes, helping to keep down cockroach numbers.