Harvestmen, Daddy Longlegs, Harvest Spiders
Opiliones (Order)
Order Opiliones (Note: These are Arachnids but NOT true spiders of the order Araneae)
Physical Description
Unlike true spiders, harvestmen have a compact body where the cephalothorax and abdomen are broadly joined as a single oval unit. They lack a thin 'waist' or pedicel. They have two eyes on a central turret (ocularium) and no silk glands.
Size Estimate
The central body is typically 2-10mm, while the legs can span 20mm to over 100mm. The image shows a massive cluster of thousands of individuals.
Coloration & Markings
Generally shades of brown, gray, or black. Some species have a 'saddle' marking on the back. In large clusters, they appear as a solid dark, fuzzy mass.
Web Type
None. Harvestmen do not possess silk glands or spinnerets and cannot build webs.
Eye Arrangement
A single pair of eyes located on a small bump called an ocularium, situated on the top-middle of the cephalothorax.
Leg Characteristics
Extremely long, thin, and spindly legs. They have seven segments, with the end segment (tarsus) often being highly flexible and multi-articulated for sensory use.
Venom & Safety Information
Venom Information
Non-venomous. Contrary to urban legends, they do not possess venom glands or fangs to deliver venom.
Medical Significance
Zero medical significance. They cannot bite humans effectively and have no venom. They are purely a nuisance when they aggregate in large numbers.
Safety Recommendations
No action is needed as they are harmless. If the cluster is on your home, a gentle sweep with a broom or a spray of water will disperse them without harm.
Habitat & Behavior
Habitat & Range
Found worldwide on every continent except Antarctica. They prefer damp, shaded areas like forests, under logs, leaf litter, and frequently on the exterior walls of man-made structures.
Behavior & Temperament
Famous for forming dense aggregations (clusters) for protection against desiccation and predators. They are docile and completely harmless to humans. If disturbed, they may bob up and down rapidly or release a pungent scent.
Diet & Prey
Omnivorous and opportunistic. They eat small insects, fungi, decaying vegetable matter, and dead organic material. They use their small chelicerae (pincers) to tear food.
Seasonal Activity
Peak activity occurs in late summer and autumn (hence the name 'Harvestmen'). Aggregations are most common during these cooling months.
Description
These arachnids are frequently mistaken for spiders but are more closely related to scorpions. In late summer and autumn, they often gather in massive, pulsating clusters on walls or trees, a behavior thought to regulate temperature and moisture.
Key Features
Single body unit (no waist), two eyes on a turret, eight long thin legs, and the lack of silk-spinning abilities.
Similar Species
Cellar Spiders (Pholcidae), which are true spiders with two body segments, 6-8 eyes, and the ability to spin webs.
Life Cycle
Females lay eggs in soil or crevices using an ovipositor. They typically live for about one year, often dying after the first frost, though some species overwinter as adults.
Ecological Importance
Vital decomposers and scavengers that help clean up organic debris and control small pest populations in gardens.
Conservation Status
Generally stable and common; not currently listed as threatened, though sensitive to heavy pesticide use.
Interesting Facts
The urban legend that they are 'the most venomous spiders in the world but have too small mouths to bite' is entirely false; they have no venom at all. They are also known to self-amputate (autotomy) legs to escape predators.
Photography Tips
To photograph the aggregation, use a macro lens to capture the individual bodies within the mass. For identification, a clear shot of the 'turret' eyes on top of a single body is best.
User Notes
Growing up the wall
Identified: 2026-07-11T15:32:28.540911