What two species of spiders found in Utah are known to be poisonous to humans?

The two species of spiders found in Utah that are known to be poisonous to humans are the black widow and the hobo spider. The black widow spider is easily identifiable by its glossy black body and the distinctive red hourglass marking on its abdomen. Its venom is neurotoxic and can cause serious health issues in humans, though fatalities are rare with prompt medical treatment.

The hobo spider, while less notorious than the black widow, has venom that can cause significant skin lesions and other health effects in humans. It is important to note that the severity of a bite from either spider may vary based on individual reactions and the quantity of venom introduced.

Knowing these two species is crucial for understanding potential health risks associated with spider encounters in Utah. The other options include spiders that either do not pose a significant threat to humans or are known for different characteristics that do not involve venom harmful to humans.