[5] When threatened, they sometimes curl up or release a noxious liquid that contains large amounts of benzoquinones which can cause dermatological burns.

Though capable of releasing irritating and foul-smelling liquid from ozopores when aggressively disturbed, they can typically be safely handled by humans and are not uncommon on the arthropod pet market.

[8] Their cuticle is somewhat water permeable, so they seek out damp or humid environments and have exhibited specific behaviors in response to desiccation stress.

In some regions Narceus americanus seems to be subject to predation by an as yet unidentified organism that eats the head and the first few segments of the body, discarding the rest of the carcase.

The observation is interpreted as reflecting the fact that some predator has discovered that only the anterior part of the animal is non-toxic.

[12] Males mate via transfer of a spermatophore, and females are able to store this sperm to fertilize eggs at a later time.

The number of body segments and leg pairs are increased with each molting, and there is no parental investment after egg hatching.