[header] How to identify a mouse spider [title] Look for thick and stocky legs. [step] Since the mouse spider is a ground spider, they have very thick and stocky (almost muscular) legs. Female mouse spiders, too, have thicker legs than male spiders. 
In addition, the male mouse spider may have long palps that appear as an extra pair of legs. [title] Check to see if they are 20 to 35 mm (.