Earwigs are nocturnal; they often hide in small, moist crevices during the day, and are active at night, feeding on a wide variety of insects and plants. Damage to foliage, flowers, and various crops are commonly blamed on earwigs, especially the common earwig Forficula auricularia.
Earwigs undergo an average of 5 molts over the course of a year, their average life expectancy, before they become adults. Many earwig species display maternal care, which is uncommon among insects. Female earwigs are known to take care of their eggs, and even after they have hatched as nymphs will continue to watch over offspring until their second molt. As the nymphs molt, sexual dimorphism such as differences in pincer shapes begins to show.
Earwig fossils have been found in different places. Some of those specimens are now included in the extinct suborder Archidermaptera dating back to the Late Triassic. Many orders of insect have been theorized to be closely related to earwigs by many authors, though Grylloblattaria is the most likely.