Wolf spiders are venomous and their venom is poisonous. Bites that penetrates the skin can cause serious pain, swelling and itchiness. Some people only experience the symptoms for a few minutes while others get a wound that takes a few days to heal.
Like the black widow spider, the brown recluse spider bites in defense and does not bite humans instinctively. They will bite humans when the clothing they are hiding in is worn. The brown recluse spider bite is painful and can produce an open, ulcerating sores even death.
The venom of a black widow spider is a neurotoxin and is used as a defense. Black widow spiders do not bite humans instinctively. The black widow spider bite can cause severe pain. Young children and the elderly are especially susceptible to a severe reaction to a black widow spider bite.