As in some other arachnids, the first pair of legs is modified to serve as sensory organs, and are held clear of the ground while walking.

[10] Their exoskeleton is very weakly sclerotized compared to other arachnids, which is the reason why fossils are so rare, and go no further back than 99 million years ago in Burmese Amber.

[3] They need a damp environment to survive, and they always hide from light, so they are commonly found in the moist earth under buried stones and rocks.

Terrestrial Palpigradi have hydrophobic cuticles, but littoral (beach-dwelling) species are able to pass through the water surface easily.

[6] However, their chelicerae have been described as "more like a comb or brush than the forceps of a predator", and the species Eukoenenia spelaea has been shown to feed on cyanobacteria ("blue-green algae").

[6] Palpigradi is split into two families, differentiated by the presence of ventral sacs on sternites IV–VI in Prokoeneniidae, and their absence in Eukoeneniidae.