The term “daddy long legs” often causes confusion because it refers to multiple distinct creatures with long, slender appendages. Understanding the specific group is key to accurately determining their leg count and other characteristics.
Unpacking the “Daddy Long Legs” Name
The common name “daddy long legs” is broadly applied to three different types of arthropods.
One group includes harvestmen, which are arachnids belonging to the order Opiliones. These creatures are related to spiders but are not true spiders themselves. Their long legs contributed to their popular nickname.
Another creature known as “daddy long legs” is the cellar spider, scientifically classified under the family Pholcidae. These are true spiders. They are frequently found in homes and basements, leading to their common name.
The third animal often called “daddy long legs” is the crane fly, which belongs to the insect order Diptera, specifically the family Tipulidae. These winged insects are sometimes mistaken for oversized mosquitoes due to their appearance. Their long legs also contribute to the shared colloquial name.
Counting Their Legs
The number of legs an animal has directly relates to its biological classification.
Harvestmen, being arachnids in the order Opiliones, consistently possess eight legs. This leg count is characteristic of all arachnids, a class that also includes spiders, scorpions, and mites.
Similarly, cellar spiders, which are true spiders and thus also arachnids, have eight legs.
In contrast, crane flies, classified as insects, have six legs. Insects are characterized by their three body segments and six legs. Their long appearance can sometimes obscure this, but they adhere to the typical insect body plan.
Beyond the Legs: Key Distinctions
Beyond leg count, these three “daddy long legs” creatures exhibit other biological differences.
Harvestmen
Harvestmen have a body where the cephalothorax and abdomen are broadly joined, making them appear to have a single, oval body segment. They possess pincer-like mouthparts and do not produce venom. Harvestmen are omnivores, consuming small insects, decaying plant matter, fungi, dead organisms, and even feces.
Cellar Spiders
Cellar spiders, however, have two distinct body segments: a cephalothorax and a clearly separated abdomen. They have fangs and venom glands, but their fangs are short, and their venom is considered weak, posing no danger to humans. Cellar spiders are predators that build irregular webs to catch a variety of insects, including mosquitoes, gnats, moths, flies, and even other spiders.
Crane Flies
Crane flies, as insects, feature three distinct body parts: a head, thorax, and abdomen. They lack fangs and venom, and their mouthparts are not designed to bite or pierce human skin. Adult crane flies have very short lifespans and may not eat at all, or they might feed on nectar or pollen. Their larvae, however, consume plant roots or decaying organic material.