Description

• The spruce-fir moss spider is a type of mygalomorph spider, which is a subgroup of spiders. At a length of only 3 to 4 millimeters at adulthood, the spruce-fir moss spider is the smallest known member of the mygalomorph group. The color of these spiders is brown and can range from a light brown to a dark, almost red brown.
  
  

Webs

• The spruce-fir moss spider constructs a tube-shaped web in the area between the moss for which it is named and the rock surface to which the moss is attached. Unfortunately, there have been no recorded observations of any prey being found in the web of a spruce-fir moss spider, adding to the ambiguities about its diet.
  
  

Lack of Observations

• Just as there have been no observations of prey caught in the web of a spruce-fir moss spider, there have never been observations of spruce-fir moss spiders taking prey in the wild. The endangered status of these spiders as well as the relatively limited amount of time since their discovery has made their hunting and eating habits a mystery.
  
  

Springtails

• While there have been no direct observations of the spruce-fir moss spider taking prey or capturing prey in its webs in the wild, the region it inhabits has an abundance of springtails, a type of anthropod. The theory among many researchers is that the proximity of the primary habitat of the spruce-fir moss spiders to such an abundance of springtails suggests these anthropods are the primary source of food for the spiders.