When I was young, I believed that daddy longslegs, or harvestmen, were spiders. They do have eight legs and both are classified as arachnids, but they are not spiders. Unlike spiders, they have one body part and don’t spin webs. Spiders have two body parts (cephalothorax and abdomen) and insects three (head, thorax, and abdomen.) The number of eyes also differs. Most spiders have eight eyes, while daddy longlegs have two. In addition, they don’t have fangs or produce venom. Daddy longlegs will shed a leg if threatened.

An informational text in the Smithsonian Backyard Series: