Cellar Spider

Quick Overview

Size: 2-3” 

Characteristics:

The cellar spider is about the size of a half-dollar coin when it is measured with its legs outstretched. It is light tan to gray with dark contrasting markings and a tiny body.

Habitat 

Cellar spiders typically live in naturally protected areas like rock piles and caves outside. They can also be found indoors, where they set up shop in cellars, basements, garages, crawl spaces, and other dark, undisturbed areas.

Behavior 

Cellar spiders are frequently found in homes and outdoors in most parts of the country throughout the year. They often overwinter indoors in heated structures. It takes a year for these spiders to mature and they can live for another two years as adults. 

What does a cellar spider look like?

Cellar spiders are almost always found in their thin messy cobwebs. These creatures are light tan to dark gray in color and have numerous contrasting markings in darker shades. They are small and thin with noticeably long, narrow legs. Females are much larger than males. 

It is important to note that, due to the brown hue, cellar spiders are often mistaken for other more dangerous species like brown recluses. However, you should be able to tell them apart because cellar spiders have legs that are longer and thinner than those of brown recluses. They are also frequently mistaken for daddy-long-legs, which are not even spiders at all.

What is the habitat of a cellar spider in Florida?

When found outside, cellar spiders are usually in caves, crevices, or other protected places. Inside, they can be found in damp basements, cellars, garages, crawl spaces, and other quiet areas. 

They can be found in climate-controlled structures year-round and are often seen in ceilings and corners, where they typically hang belly-up. When found indoors, these spiders are the natural enemy of large house spiders. 

What are the behaviors of a cellar spider?

Cellar spiders are known for creating loose, messy webs that are arranged horizontally and in a highly irregular manner. They continuously add to their webs and don’t eat or ruin their webs to make new ones, as some species do.

These long-lived spiders lay eggs that are deposited in clusters of up to sixty and wrapped in a thin layer of silk. If the web or eggs are threatened, the spider will rapidly vibrate in a circular motion to detract attention away from the eggs. 

How dangerous is a cellar spider?

Some people say that cellar spiders are venomous, but this is not true. In fact, cellar spiders can be somewhat advantageous in the home as they keep populations of large house spiders in check. They also feed on other pests like flies and wasps. 

What should I do if I’m bitten by a cellar spider?

Cellar spiders are not known to bite humans. The biggest threat that they pose is the large amount of webbing that they produce on ceilings and in corners. They keep adding to their webs, which can lead to an eyesore if you don’t take the time to tear the webs down. Other than that, they pose no threat.

Taxonomy:

Kingdom: Animalia

Subkingdom: Bilateria

Infrakingdom: Protostomia 

Superphylum: Ecdysozoa

Phylum: Arthropoda

Subphylum: Chelicerata

Class: Arachnida 

Order:  Araneae

Family: Pholcidae

Genus & species: Pholcus phalangioides

Cellar Spider Facts and Myths

1. Myth: Cellar spiders are daddy-long-legs.

The two are actually not the same. Daddy-long-legs are technically harvestmen, which look like spiders but are actually more closely related to scorpions. 

2. Fact: Cellar spider webs aren’t sticky.

This is highly unusual for a spider! Cellar spider webs aren’t sticky – instead, it is the complex structure of the web that traps prey instead of any stickiness. 

3. Myth: Cellar spiders are venomous, but they just don’t have the jaws they need to bite.

Technically, all spiders are venomous. Cellar spider venom just isn’t that strong. It isn’t harmful to humans and the jaws are too weak to pierce through human skin. 

4. Fact: Cellar spiders have a unique defense mechanism.

When threatened, cellar spiders will violently vibrate their webs to make it hard for their attackers to see them. It’s also quite intimidating to any potential attackers, too!

5. Fact: Having a few cellar spiders in your house is a good thing.

While the web might prove to be an annoyance, having some cellar spiders in your house is actually a good thing. Not only do they feed on house spiders, but they also keep down populations of other pests (like flies). 

Photo Credit: Olei, CC BY-SA 2.5 https://creativecommons.org/licenses/by-sa/2.5, via Wikimedia Commons