Venom

Katipo spider

All spiders have venom, which they use to overcome prey.
The jaws of most spiders are unable to pierce human skin or, if they can, the venom in the majority of species is not strong enough to have a bad effect.
Spiders in the Latrodectus group (widows/ redback) have a potent venom affecting us.
The most potent spider venom in the world to humans is the Sydney funnelweb spider, which does not occur in New Zealand.