Pholcidae

Some spiders have very long legs.

These spiders live in dark, damp spots. You might find them in cellars or under rocks. They build messy webs to catch food.

When they feel a threat, they shake fast. This shaking helps them stay safe. It makes it hard for others to see them.

They can also catch other spiders. They use silk to wrap up their prey. This helps them eat from a safe distance.

These spiders are found almost everywhere on Earth. They are not dangerous to people.

Pholcidae is a large family of spiders.

There are more than 2,000 species in this group. Many people call them cellar spiders or daddy long-legs. These spiders live on every continent except Antarctica. They like dark, damp spots like caves or attics.

Pholcids have very long, thin legs. They have two body parts. One part is the prosoma. The other part is the opisthosoma. Most have eight eyes in two groups. Some species only have six eyes.

Their webs are messy and do not stick. Instead, they use silk to wrap up prey. Some species even hunt other spiders. They can eat house spiders or redback spiders.

If a spider feels a threat, it moves fast. This is a threat response. The spider shakes or vibrates in its web. This may make it hard for predators to see them. It might also help them catch more insects. Some people think they are very dangerous. This is not true. Their venom is not a big risk to humans. They can bite, but it does not cause major harm.

Pholcidae is a large family of spiders found all over the world. They live on every continent except Antarctica. Many people know them by names like cellar spiders or daddy long-legs spiders.

This group includes more than 2,000 different species. They are divided into 94 different genera, which are groups of related species. These spiders often live in dark and damp places. You might find them in caves or under loose tree bark. They also like to build webs in the high corners of attics or cellars in human homes.

These spiders have a very distinct way of looking and moving. Most have extremely long and thin legs with flexible feet. Their bodies have two main parts called the prosoma and the opisthosoma. The prosoma is the front part, and it can be domed or have a small pit. The opisthosoma is the back part, which can be long or short. Most pholcids have eight eyes arranged in two groups of three. Some species only have six eyes because they lack a middle pair. When they walk, they often use an alternating tetrapod gait. This means they move their legs in a specific pattern, like first a right leg then a left leg.

Pholcids use a very interesting way to catch their food. Their webs are messy and irregular, and they do not have any sticky properties. Instead, the spider waits for prey to touch the web. When they detect something, they quickly wrap the prey in silk. They might eat the insect right away or save it for later. After they finish eating, they clean their web by dropping the leftover bits. Some species are even brave enough to hunt other spiders. They can invade the webs of house spiders or redback spiders to eat them.

When a pholcid spider feels threatened, it performs a special threat response. If something touches the web, the spider begins to vibrate or shake very rapidly. This is why some people call them vibrating spiders or gyrating spiders. This shaking can happen in a circular rhythm. It might even make the spider move more than its own legs can. This movement might make it hard for a predator to see them. It could also be a way to signal to a rival spider. Some scientists think this shaking helps them catch insects that just brushed the web.

There is a famous urban legend about these spiders. Many people believe they have the most potent venom of any spider. They think the fangs are just too small to hurt humans. However, this is not true. Pholcid spiders can bite humans, but their venom is not medically significant. This means it is not dangerous to people. In 2004, the show MythBusters tested this idea. They found that the venom was much weaker than a black widow's venom. One host even felt a tiny, short-lived burning sensation from a bite. Despite the myths, these spiders are generally passive toward humans.

The Pholcidae are a large family of araneomorph spiders found on every continent except Antarctica. This family includes more than 2,000 individual species. They are organized into 94 different genera, which are groups of related species. People often call them by many names, such as cellar spiders, daddy long-legs, or vibrating spiders.

While they share the name "daddy long-legs" with harvestmen and crane flies, they are biologically very different. Harvestmen have only one pair of eyes and a single body segment. In contrast, pholcids are true spiders with two distinct body segments.

Pholcids have a very specific physical structure. Their bodies consist of a prosoma, the front section, and an opisthosoma, the rear section. The prosoma might be shaped like a dome or have a small pit in the center. The opisthosoma varies greatly in shape; it can be long and cylindrical, short, or even pointed at the back. Most pholcids have eight eyes arranged in two groups of three, sometimes with a small middle pair. However, some genera like Modisimus and Spermophora only have six eyes. Their legs are famously long and thin, featuring flexible tarsi, which are the segments at the very end of the legs.

These spiders are masters of a unique hunting method. Unlike many other spiders, pholcid webs have no adhesive or sticky properties. Instead, the web is built in a messy, irregular shape to trap prey. When a pholcid detects an insect in its web, it quickly envelops the prey in silk-like material. The spider may eat the meal immediately or store it for later. Once the spider is finished feeding, it cleans the web by unhooking the remains and letting the carcass drop away.

When a pholcid feels threatened, it uses a specialized behavior called a threat response. If something touches the web, the spider begins to vibrate or gyrate rapidly. This movement can sometimes settle into a circular rhythm. The spider might oscillate in tune with the elasticity of the web, creating a motion larger than its own legs. This behavior has earned them the name "vibrating spiders." Scientists believe this might confuse predators or signal to rivals. It may also help the spider capture insects that have just brushed against the web.

Pholcids have a very interesting diet that includes other spiders. While they primarily eat insects, certain species will invade the webs of other spiders. They may eat the host spider, its eggs, or its captured prey. Some species even mimic the vibrations of struggling prey to lure a host spider closer. They are known to prey on Tegenaria funnel weaver spiders, redback spiders, huntsman spiders, and house spiders. Because they eat certain species, they may actually be beneficial to humans by keeping spider populations in check.

The history of this family was first established by Carl Ludwig Koch in 1850. Since then, researchers have identified many different species across the globe. Their size varies significantly depending on the species. For example, Spermophorides lascars is just over 1 millimeter long. Meanwhile, Artema atlanta can reach a body length of 11 mm. They are highly adaptable and can be found in dark, damp places like caves, under rocks, or in abandoned mammal burrows. In human homes, they prefer undisturbed areas like attics and cellars.

There is a common urban legend regarding the danger of these spiders. Many people believe pholcids possess the most potent venom of any spider, but that their fangs are too weak to bite humans. This is a misconception. Pholcids do have a short, hooked fang structure called an uncate. While they can bite humans, their venom is not medically significant and is relatively weak. In 2004, the television show MythBusters tested this. They found the venom was much less toxic than that of a black widow. One host even experienced a bite that caused only a mild, short-lived burning sensation. The legend likely exists because pholcids successfully hunt much more venomous spiders, such as the redback or members of the Latrodectus genus.