Almost all spiders bite, but fatalities from spider bites are rare, mainly due to anti-venom treatment. A common species, the grass spider, also known as the funnel weaver spider, although venomous to some species, is considered harmless to humans, according to Colorado State University Extension's website.
Grass spiders are about 3/4 inch long, are brown or light gray in color and have several dark stripes on their head. They have dark banded legs and move very quickly.
Habitat and Habits
Grass spiders build silk, funnel-shaped webs among shrubs and grass outdoors or in room corners indoors. Hiding within its web's "funnel," a grass spider swiftly ambushes and bites unwary prey straying onto the web.
The grass spider preys on small insects using its neurotoxic venom to paralyze the nervous system of its victims, which it then eats. A bite from a grass spider is considered low risk to humans.