Types of Brown & Red Spiders in Colorado

There are many spiders in Colorado and many spiders can be beneficial. Spiders will feed on other insects and can help remove pests. Most spiders live out of doors, but can wander into homes when the temperature starts to cool. While most spiders in Colorado are harmless, there are a few that are dangerous and you will need to get medical attention immediately if bitten.

  1. Funnel Weaver

    • The funnel weaver spider is a dark brown spider with black markings on its abdomen. It is also known as a grass spider as it frequently makes its nest in tall grass. This spider is harmless, but is sometimes mistaken as the dangerous brown recluse. The spider's web looks like the base of a funnel and is spun on building corners, thick grass and shrubs.

    Wolf Spider

    • The wolf spider is typically brown or grey in color. It is an active hunter and will not create a web to catch its prey. Besides the regular wolf spider, there are also burrowing wolf spiders and giant wolf spiders. Female wolf spiders will carry the eggs on their backs and when the young are hatched, they will live on the mother for a few weeks. Wolf spiders will only go into a home when the buildings interrupt their natural habitat. These are not dangerous, though giant wolf spiders can bite.

    Brown Recluse

    • The brown recluse is only found in the southern area of Colorado as much of the state is too cold for this spider. These spiders are pale brown and only have three eyes. The recluse venom is dangerous to humans and can create ulcerous wounds if a human is bitten. Many times the brown recluse is mistaken for a funnel spider, but the recluse has violin-shaped markings near the eyes.

    Black Widow

    • The black widow spider is a dangerous spider that has red marks on the underside of its body. The red marks form an hourglass. It is the female black widows that are dangerous as male spiders do not have long enough fangs to break the skin. While black widows are not found extensively in Colorado, they are present in the warmer areas of the state. Black widow webs are typically found in dry, dark and sheltered places. Most humans that are bitten have disturbed the spider from its web.