All spiders possess venom which they use for paralyzing prey and for self defense against predators.
The type of venom and its effects on humans varies among species. Although most spiders are relatively harmless, the black widows and brown recluses are considered dangerous to humans and animals and should be avoided. The northern black widow L. variolus , extends down into the south but is not as common. The hourglass mark under its belly is incomplete. The brown widow L. geometricus , varies from gray to light brown with a brownish yellow hourglass pattern.