Barn Spider

Barn spiders are a species of spider that is common in North America, specifically in southern parts of Canada and the northeastern United States. They are about ¾ of an inch long and have yellow/brown specks all over their bodies. Like other orb weaver spiders, the barn spider commonly builds a new web every day. The barn spider is most notable for its appearance as Charlotte in the classic children’s book Charlotte’s Web.

4 Incredible Barn Spider Facts

• The barn spider became particularly famous after its appearance in the famous book Charlotte’s Web by E.B. White. In this book, the barn spider, Charlotte A. Cavatica, plays a major role.
• Like most spiders, the barn spider has very poor eyesight.
• The barn spider catches its prey by sensing their vibrations instead of relying on its other senses, such as sight or smell. 
• Barn spiders are nocturnal and find their food at night. During the day, they retract their web and build it again in the evening.

Barn Spider Scientific Name

Scientific name: Araneus cavaticus

Scientifically known as Araneus cavaticus, the barn spider was named by a biologist Keyserling in 1882. However, the species was given several other scientific names that were very similar. These include:

1. Epeira cavatica
2. Epeira cinerea
3. Aranea cavatica

The species is commonly known as the Hentz orb-weaver after Nicholas Marcellus Hentz, who was the first to collect and classify North American spiders and managed to write down his findings and descriptions of 141 spider species in Boston Society of Natural History’s journal.

Barn Spider Appearance

Barn spiders are yellow or brown in color, with specks on their bodies and stripes on their legs. The stripes vary in color, from dark shades of brown to grey and black. Their undersides are black with white marks on them. Overall, they can have quite a diverse color range, which is why they are commonly mistaken for other species of spiders.

Like most spiders, the barn spider is very small but can still be seen by the naked eye. They’re generally about three-quarters of an inch long, but they can grow up to an inch. On average, male barn spiders are slightly smaller than the females at around ¼ to ½ inch as opposed to ¾ inch. Their bodies have a round shape, with four legs on each side of their body. The legs have a spiny appearance. The spider’s abdomen is hairy and has many bumps on it.

Only female barn spiders construct webs. This web is mostly spiral-shaped and flat.

Barn Spider Evolution And History

There has been little research on the evolution of the barn spider and its origins. Spiders as a whole evolved around 400 million years ago, and arachnids were likely part of the first wave of animals to leave the water and dwell on land. Spiders originally evolved from Chelicerata subphylum which is a branch of Arthropods that includes modern-day animals like sea spiders and scorpions, as well as land spiders and other spider-like creatures.

Barn Spider Behavior

Barn spiders are a nocturnal species of spider, meaning they hunt their prey at night and retract their webs during the day. Then in the evening, the female builds another web to capture prey. The spider sits in the web at night, waiting for insects to get trapped in it.

Barn spiders, like all other spiders, prefer to live alone as solitary species. The males are seldom seen unless they want to mate. The females build the web and keep their young close in the beginning. However, nurturing aside, these species live alone for most of their lives. These spiders can also be aggressive towards each other if another spider tries to make a web in the same area as them or tries to inhabit their web.

When threatened, barn spiders bounce up and down in their webs to appear intimidating. They also move their web up and down to assert control over it. 

This unique behavior can also be seen if there is prey in the barn spider’s web and it wants to throw off any leaves or debris off the prey. Once the prey has been caught and consumed, the barn spider retracts its web.

Barn Spider Habitat

As their name suggests, barn spiders live inside or around wooden structures such as barns or sheds. They can also be found in boats or any other wooden corners that provide shelter. Out in the wild, they can be found near cliffs, on trees, or in crevices. So whether in urban areas or not, this spider species can survive. These spiders inhabit many areas of the United States and Canada.

Barn Spider Diet

Barn spiders are carnivorous creatures that feed on prey that gets stuck in their web at night, between dawn and dusk. They feed on several different types of insects, such as beetles, ants, moths, flies, and mosquitoes. When the spider catches its prey it it injects it with its venom and then sucks out the blood and juices of the insect.

What Eats the Barn Spider? 

Barn spiders are preyed on by any animals that happen to be bigger than them. These include, but are not limited to, birds, lizards, and other spider species that are larger than the barn spider or have poison that could kill the barn spider.

What Does the Barn Spider Eat?

Barn spiders are carnivorous, and their diet is largely based on other insects, such as beetles, moths, and ants. They have a poor sense of vision and hunt their prey through vibrations and their webs. Once prey is trapped in their web, barn spiders wrap it in their web’s silk to feed on it. They then inject the prey with a venomous bite. When the prey dies, the spider begins to suck out its blood and juices of it. It covers its prey’s body with digestive fluids so that it disintegrates more quickly. The barn spider recycles its web by eating it.

Barn Spider Predators and Threats

Common predators of the barn spider are birds, lizards, and other larger spider species. Humans also pose a threat to the barn spider since they live typically live in and around man-made structures. Nevertheless, they survive in urban and natural environments, so their population is still stable. Hence their conservation status is of Least Concern.

Barn Spider Reproduction

Male barn spiders impregnate one or more females in their lifespan. However, the males will first have to find a mate, which can be a hefty task since the spiders are solitary animals for most of their lives. 

To make matters a bit easier for the male, the female communicates to the male that she is sexually mature through her dragline, which leaves a trail of pheromones. A dragline is a string of silk dangling from the female’s backside. The males smell these pheromones and use the trails to attempt to find the female.

Once the male has located a female, he fights any other males that might be hovering around the female to mate. Whichever male emerges victorious gets to mate with the female. But before doing so, the male needs to signal to the female that he belongs to the same species as her and wishes to mate. He does so by attaching a thread to the female’s web and sending out specific vibrations as a form of signal for mating. If the female recognizes the male spider as the same species, the female then positions herself for sex. Then the male deposits the sperm in the female’s genital opening. The female stores these sperm near her ovaries, and fertilization occurs when she is ready to lay eggs about a month later. A female barn spider can lay around a hundred eggs at once.

Barn Spider Babies

The babies of a barn spider are known as barn spiderlings. Until hatching, the mother keeps the eggs safe from predation by wrapping them up in silk in an egg sac. There is little known about barn spiderlings, except that they become independent very soon after hatching.

Barn Spider Lifespan

On average, barn spiders can live for about a year. And during their lives, they face some common diseases as they age. These include:

1. Dehydration – if the barn spider is living in a scorching environment with little to no moisture, or an area facing drought, it can become dehydrated and begin to shrink in size over time. While they might be able to survive long enough without water, harsh weather conditions can affect them more in the later months of their life.
2. Fungal issues – Sometimes, fungus and mold can grow onto the bodies of an aging barn spider. If the environment is humid, there can be mold infestation, and the same mold can grow onto the spider’s body. 
3. Nematode worms – An infestation of nematodes in the bodies of barn spiders, particularly old ones, can lead to a quick death.
4. Mites –  In hot, humid climates, mites can also penetrate the spider’s bodies.

Barn Spider Population

The exact number of barn spiders all over the world is unknown. However, their conservation status is Least Concern as of yet, owing to their adaptability to urbanization.

Similar Animals:

• Grass Spider: This spider species is mainly found in grass.
• Peacock Spider: This spider has beautiful colors that the males showcase during courtship.
• Wolf Spider: A carnivorous spider species that strikes its prey like a wolf!
• Orb Weaver: Barn spiders are a type of orb weaver.

1. Hobby Farms, Available here: https://www.hobbyfarms.com/are-barn-spiders-poisonous/
2. Missouri Department of Conservation, Available here: https://mdc.mo.gov/discover-nature/field-guide/barn-spider
3. Spider Identifiactions, Available here: https://spideridentifications.com/barn.html