Welcome to Colorado spiders. Most long time residents of the state have come to know someone involved in a two decade long citizen science project that surveys the spiders of Colorado.
The survey is sponsored by the Denver Museum of Nature & Science. Over the course of the survey, the museum has accumulated over forty thousand spider specimens.
A quick review of the database reveals a bit of messiness because the results are organized by counties, and in some instances cities.
Downloading the Denver and Denver County data, and filtering for duplicate species reveals that over the course of twenty years, approximately 166 spider species now occupy the Denver spider checklist.
The two cobweb spiders most people fear, the Western Black Widow and Southern Black Widow make the list. The Western Black Widow is the dominant species in all of Colorado with the Southern Black Widow present due to accidentally hitching a ride.
The picture shows a female Western Black Widow.
Orb Weaving Spiders
Zygiella x-notata
There’s around one hundred orb weaving spider species, many of them regionally situated. Some of the species come in a range of colors.
Here’s a few of the more common species with a wider geographical range. See Orb Weaving Spiders for more detail.
Yellow Writing Spider bottom view
Yellow Writing Spider top view
Banded Writing Spider
Cross Orb Weaving Spider
Araneus nordmanni
Trashline Orb Weaver
Gray Cross Spider
Larinioides patagiatus orange shade
Larinioides patagiatus brown shade
Larinioides patagiatus bottom
Sleeping Orb Weaving Spider
Long-jawed Orb Weaver
Long-jawed Orb Weaver side view
Crab Spiders
Flower Crab Spider
It’s sometimes difficult to identify Crab Spiders using body color. Body hair and eye configuration can help. Here’s a few examples.
Flower Crab Spider yellow
Yellow and Red Northern Crab Spider
Northern Crab Spider white
Northern Crab Spider yellow
Swift Crab Spider
Xysticus cristatus
Xyxtcuis Eyes
Slender Crab Spider
Ground Crab Spider
Jumping Spiders
Bold Jumping Spider
A couple hundred jumping spider species inhabit residential areas, many with limited ranges. Body color can change over the course of time, as with the species presented here. See Jumping Spiders for more complete information.
Bold Jumping Spider
Bronze Jumping Spider Female
Bronze Jumping Spider Male
Zebra Jumping Spider
Zebra Jumping Spider Side
Zebra Jumping Spider Eyes
Lynx Spiders
Striped Lynx Spider Eyes
Lynx spiders can be abundant in residential areas. The following pictures might help with ID.
Striped Lynx Spider top
Western Lynx Spider Eyes
Western Lynx Spider Female
Western Lynx Spider Juvenile
Western Lynx Spider Male
More Spiders and Relatives
Ground Spider
Funnel weaving spider Hololena nedra
Pirate Otter Spider
Opaline or Daddy Long Legs
Dog Tick Female
Dog Tick Male