[4] Harvestmen (Opiliones), which share the name "daddy longlegs", also have long and thin legs but have only one pair of eyes, and their body appears to be a single segment.

[5] There is variation in size, ranging from just over 1 millimetre (Spermophorides lascars) to 11 mm (Artema atlanta) in body length.

These webs are constructed in dark and damp recesses such as in caves, under rocks and loose bark, and in abandoned mammal burrows.

Some species of Pholcidae exhibit a threat response when disturbed by a touch to the web or entangled large prey.

The arachnid responds by vibrating rapidly in a gyrating motion in its web, which may sometimes fall into a circular rhythm.

The movement may make it difficult for a predator to locate or strike the spider, or may be a signal to an assumed rival to leave.

Vibrating may also increase the chances of capturing insects that have just brushed their web and are still hovering nearby, or further entangle prey that may have otherwise been able to free itself.

Indeed, pholcid spiders do have a short fang structure (called uncate due to its "hooked" shape).

Brown recluse spiders also have uncate fang structure, but are able to deliver medically significant bites.

[17] During 2004, the Discovery Channel television show MythBusters tested the daddy long-legs venom myth in episode 13, "Buried in Concrete".

After measuring the spider's fangs at approximately 0.25 mm, Adam Savage inserted his hand into a container with several daddy-long-legs, and reported that he felt a bite which produced a mild, short-lived burning sensation.