Harvestmen, commonly known as daddy long-legs or opilionids, are arachnids that belong to the Order Opiliones. Daddy long-legs refer to its long and slender legs which they use for walk and climb. Opiliones comes from the Greek word for "shepherd," which alludes to its long legs. While the term daddy long-legs is often used interchangeably, not all daddy long-legs are harvestmen. Additionally, the term harvestmen applies only to male Opiliones, as females are called harvestwomen. Other synonyms for harvestmen include granddaddy-longlegs, shepherd spiders, and harvest spiders. These arachnids play an essential ecological role in consuming primarily plant materials and dead animals, which also makes them a beneficial predator to have around.