Every Spider HIDING In Your Home Explained in 10 minutes

[00:00:00]American house spider.

[00:00:01]50 homes were searched room by room in one survey, and this spider was living in all 50 of them. Sitting in roughly two-thirds of every room checked.

[00:00:11]Ceiling corners, window frames, the gap behind the basement stairs. It's web has no wheel or pattern to it, just a snarl of lines strung across a corner with a few sticky threads let down toward the floor. Look closely at the body and the resemblance starts to bother people. The round abdomen and the way the legs fold sit close enough to a widow's that this spider gets reported as one constantly.

[00:00:34]The giveaway is underneath. No red hourglass, ever.

[00:00:38]Its venom belongs to the same broad neurotoxic class as a widow's. The bite is documented as no danger to a person at all. The hunting is stranger than the web suggests. When something lands that is too quick to hold, the spider stands off at a distance and flings silk at it, hauling the line back in until the target is bound. Large females have been watched baiting the trap on purpose, dangling the drained husk of an old fly to draw in baby lizards.

[00:01:05]A single female builds more than 12 egg sacs across her life. Each holding somewhere between 140 and 380 eggs.

[00:01:13]Jumping spiders raid these webs.

[00:01:16]Sometimes the raider mis-times its approach by a fraction, sticks fast in the tangle, and is eaten in the web it came to rob. That puts the house spider fairly low in a food chain that spiders run on each other.

[00:01:28]Further up that same chain, feeding on spiders instead of flies, sits the cellar spider. Cellar spider. The long-legged one hanging in the corner of the garage and the subject of the most repeated spider claim on Earth. The deadliest venom in the world with fangs too short to break your skin.

[00:01:47]Both halves of that fail. Its fangs run about a quarter of a millimeter longer than human skin is thick. The venom barely troubles a mammal. Touch the web and the spider vanishes while staying exactly where it is. It grips the silk and whirls its whole body in tight fast circles until the outline smears into something a bird or a wasp cannot aim at. It eats other spiders. A cellar spider walks into a stranger's web, takes a thread in one leg, and plucks it in the rhythm of a struggling insect, then holds still. The owner comes out to collect a meal and meets the thing that made the signal. Its legs turn distance into a weapon. Prey many times its own size gets silk thrown over it from beyond arm's reach and wrapped tight before it can turn around. Males search out the largest female they can find and pass over the smaller ones. The venom rumor may have grown from something real. This spider kills species with genuinely dangerous venom, the redback among them, by getting its bite in first. Black widows are on that list, too. A cellar spider never has to touch what it kills. Push that further, past silk altogether, and you get the wolf spider. Wolf spider, bulky, thick-legged, and hairy enough that it accounts for a fair share of the panic calls about an escaped pet tarantula loose in a house. Its brown markings get it mistaken for a recluse, as well. The venom is on record as no particular danger to people. It spins no capture web. It walks and it runs prey down on foot with eyesight ranked second among spiders only to the jumpers. Sweep a flashlight across a lawn at night and the ground answers back. A mirror-like layer behind each of its eyes throws the beam straight back at its source, so the spider shows up as a pair of tiny green sparks in the grass. Biologists count wolf spider populations this way, walking a field in the dark and tallying the glowing dots. The fangs are oversized and a bite genuinely hurts.

[00:03:39]Cornered, the spider almost always runs.

[00:03:41]The female carries her egg sac attached to her own spinnerets, dragging it everywhere she goes. When it opens, the spidlings climb up her legs onto her abdomen and pack themselves across her back, dozens of them, and she carries the whole load around for days. A wolf spider gets called a recluse by people who have never seen either one. That confusion goes much further with the brown recluse itself. Brown recluse.

[00:04:05]Doctors in California have been writing recluse bite on patient charts for years in a state where fewer than 20 of these spiders have ever been collected in its entire recorded history. The bite matters where the spider actually lives.

[00:04:19]Its venom breaks down tissue at the site and the wound keeps spreading outward from where it began, sometimes reaching several inches across before it stops.

[00:04:27]The violin marking everybody checks for is close to useless for telling one apart. Plenty of harmless brown spiders carry a dark shape on the back. The reliable feature is the eyes. A recluse has six of them instead of eight, set in three pairs across the front of the head. It can go a full 12 months with no food and no water and still be alive at the end of it. Then there is the arithmetic nobody quotes. Of bites that are actually confirmed as recluse bites, about one in 10 turns out to be medically significant. The other 90% close up and heal on their own. Six eyes in three pairs is odd equipment for a spider. At the opposite end of that scale, carrying the best vision in the entire group, is the bold jumping spider. Bold jumping spider. Compact, black, with a bright triangle on its back and metallic green mouth parts. And it will turn on your window sill to watch you the way a cat does. The figure attached to it everywhere is a leap of 50 times its own body length. Detailed motion capture of a close relative measured most jumps at two to five body lengths, and an earlier study topped out around four. Before it leaves a surface, it tacks a line of silk down behind it.

[00:05:38]Every single time. A missed leap means dangling on the thread and climbing back up. A defensive bite from one feels about like a mosquito. The female seals up to 170 eggs in a silk shelter and stands guard until the spiderlings walk out on their own. The attack changes with the target. Against a looper caterpillar, it comes straight in at the head from the front, where the thrashing body cannot reach it. Against a fly, it circles behind, creeps in from the blind side, and jumps before the fly registers anything at all. All of that is done on foot and by eye. The black widow feeds without moving from her corner. Black widow, by the highest published comparison, her venom runs up to 15 times more potent than a rattlesnake's, drop for drop. And no confirmed black widow bite in North America has killed anyone in decades. She hangs upside down in a loose, messy snarl of silk under a step or behind stacked firewood. Her eyesight is poor. Everything she learns about a visitor arrives as vibration through the threads, read by her legs.

[00:06:40]The silk itself is worth a moment.

[00:06:42]Strand for strand at the same thickness, it pulls against steel wire. A serious bite works through the whole body.

[00:06:49]Cramping muscle pain, nausea, and a tightening of the diaphragm severe enough to make breathing hard work. The name came out of an assumption. Females were said to eat the male after every mating. In the wild, most males finish, leave, and go on to mate again. The eating shows up mostly in glass enclosures, where the male has nowhere to escape to. A widow waits in one corner for her whole life, so almost nobody gets near her. Yellow sac spiders are the opposite kind of neighbor, and they bite more people than any other spider in North America. The yellow sac spider. Pale, small, easy to miss, and out on your walls and ceilings after dark every night, hunting on foot instead of sitting in a web. Most of its bites happen because someone rolled over on one in bed or pulled on a shirt it was inside. For years it was listed beside the recluse and the widow as one of only three spider groups in North America worth calling medically significant. That reputation for flesh destroying wounds has largely been walked back since. It builds no hunting web at all. At dawn, it spins a fresh silk sleeping tube tucked into a wall corner or a fold of curtain, sits out the daylight inside it, and abandons the whole thing that night to build a new one the next morning. Courtship starts with a break-in. A male finds a sealed sack with a female inside, taps on the outside wall of it to announce himself, then cuts through the silk to get in.

[00:08:10]The bite leaves a raised, angry-looking welt that can take 8 weeks to fade completely.

[00:08:15]>> That is a lot of ground for a spider the size of a grain of rice. For size and pure speed together, the house belongs to the giant house spider. Giant house spider. It holds the only running speed record ever awarded to a spider by the record books, clocked at just over half a meter per second, roughly 2 km an hour across a floor. On a dark carpet at that pace, it registers as a blur going past your foot. Every autumn, the males quit their webs entirely and set off walking through houses looking for females. That is the whole explanation for the spider stranded in the bathtub in September. It got in overnight, found the porcelain too slick to climb, and has been circling the drain since. For all the size and the speed, the bite carries no medical significance for people or pets, and the animal almost always runs rather than stand its ground. Where they move in, the smaller hobo spider tends to move out, simply out-hunted for the same insects in the same walls. One egg sack releases 60 or more spiderlings, and they stay together as a cluster for about a month before scattering. Whether they all make it depends entirely on the food. When prey runs thin in that huddle, they start eating each other.