Granddaddy long legs are usually harvestmen, which are not spiders. They eat small insects, mites, aphids, snails and slugs, dead insects and other dead animal matter, fungi, and plant juices. They cannot make silk and have no venom glands, so they are harmless to people.
Harvestman or Spider?
Harvestmen (order Opiliones) are arachnids, like spiders, but they are a separate group. You can tell them apart by body shape: a harvestman’s body looks like one round or oval piece, while a spider has two distinct sections. Most have two eyes on a small raised bump, and they do not spin webs. Cellar spiders, which also get called daddy long legs, are true spiders with two body sections. See what daddy long leg spiders eat for those.
What Harvestmen Eat
- Small insects and mites: including aphids, caterpillars, and small beetles.
- Snails, slugs, and earthworms: soft-bodied animals that some species hunt in damp places.
- Dead insects and other decaying matter: they often scavenge.
- Fungi and plant juices: a regular part of the diet for many species.
Harvestmen grab food with their pincer-like mouthparts and tear it into small pieces. Unlike spiders, they can swallow solid bits of food.
Odd Defenses
When threatened, harvestmen may release a smelly fluid from glands, play dead, or bob their bodies. A harvestman can also drop a leg to escape a predator, and the leg does not grow back. The detached leg twitches for a time, which distracts the attacker.
Where to Find Them
Harvestmen live in damp, shaded places such as leaf litter, under logs, in basements, garages, and on tree trunks. In fall they sometimes gather in large groups on walls and fences. They are good to have in a garden because they eat small pests.
Are They Dangerous?
No. They do not bite people or pets in any meaningful way, and they have no venom. The idea that they are the most venomous spider in the world is a myth.
See also: what daddy long legs eat and what you can feed a daddy long legs.
Bottom Line
Granddaddy long legs, or harvestmen, eat small insects, mites, snails, dead animals, fungi, and plant juices. They are not spiders, have no venom, and are harmless.
