Ever watched a spider at a water dish and wondered if it’s actually drinking? Spiders don’t sip like mammals—they have a completely different setup. This list covers the surprising ways spiders take in water, from droplet lapping to extracting moisture from prey, and what it means if you keep one as a pet. You’ll learn the real mechanics behind spider hydration and how to tell if your eight-legged friend is getting enough.
1. They Lap Up Droplets with Their Mouthparts
Spiders don’t have jaws or teeth; instead, they use a pair of appendages called chelicerae, which end in fangs. Between the chelicerae is a small mouth opening that leads to a sucking stomach. To drink, a spider presses its mouth against a water droplet and uses muscular contractions to pull the liquid in. You’ll often see a spider with its face flat against a wet leaf or the side of a dish—that’s it drinking, not just resting.
2. They Use Capillary Action in the Tiny Spaces
Many spiders, especially ground dwellers like tarantulas, have specialized setae (hairs) around their mouthparts that are hydrophilic, meaning they attract water. These hairs create tiny channels that draw water toward the mouth through capillary action—the same principle that makes water creep up a paper towel. This lets them drink from very thin films of moisture, like dew on a web or a damp substrate, without needing a visible puddle.
3. They Extract Water from Their Prey
When a spider catches an insect, it doesn’t chew—it injects digestive enzymes that liquefy the prey’s insides. The resulting soup contains not just nutrients but also a significant amount of water. The spider then sucks up this liquid, which is often its primary source of hydration in the wild. For species like orb-weavers that live in dry areas, this internal moisture can be enough to sustain them for long periods.
4. They Recycle Water from Their Own Web
Web-building spiders, particularly those in the family Uloboridae, are known to consume their old webs. The silk is made of protein, but it also absorbs moisture from the air, especially in humid conditions. By eating the web, the spider recovers both nutrients and water. This behavior is common during nightly web repairs, where the spider ingests the old silk before spinning new strands.
5. They Absorb Moisture Through Their Legs
Recent research on jumping spiders and wolf spiders has shown that they can absorb water directly through their legs, specifically at the joints where the cuticle is thinner. This is called ‘drinking through the skin’ or cuticular absorption. In laboratory tests, spiders with sealed mouths still gained weight when placed on wet substrate, proving that leg absorption is a real pathway. This is especially useful for species that live in damp burrows where the air is humid but standing water is rare.
6. They Drink from Raindrops and Dew on Leaves
In nature, spiders often drink from the droplets that collect on leaves, spider webs, and other surfaces after rain or morning dew. They’ll position themselves over a droplet and lower their head to make contact. Some species, like the fishing spider (Dolomedes), are even known to dive into water and trap a bubble of air, but they still drink by lapping at the surface film rather than submerging their mouths.
7. They Use Their Pedipalps to Guide Water
The two small leg-like appendages near a spider’s mouth, called pedipalps, play a role in drinking. While not used for chewing, they help guide water toward the mouthparts, especially when the spider is drinking from a large droplet or a wet surface. You might see a spider repeatedly touching its mouth with its pedipalps—that’s it adjusting the flow of water into its mouth.
8. They Can Go Weeks Without Drinking, But Prefer Not To
Spiders are remarkably drought-tolerant. Many species can survive for weeks without a direct drink, relying on moisture from prey and metabolic water (water produced when breaking down food). However, they will actively seek water when available. In captivity, a spider that lacks a water dish may become dehydrated, leading to lethargy or a shrunken abdomen. Always provide a shallow water dish with a sponge or pebbles to prevent drowning.
9. They Drink More When Molting
Before molting, a spider needs extra hydration to help split the old exoskeleton and expand the new one. Keepers often notice their tarantulas or jumping spiders spending more time at the water dish in the days before a molt. The extra water increases internal pressure, making it easier for the spider to push out of its old skin. After molting, they also drink to rehydrate and help the new exoskeleton harden properly.
10. They Don’t Drink from Puddles Like You’d Think
You won’t see a spider lapping from a large puddle like a dog or cat. Their mouthparts are too small, and they risk drowning. Instead, they drink from the edges of puddles, where water forms a thin film on soil or rocks. In a terrarium, a shallow dish with a wet cotton ball or a piece of sponge is ideal because it mimics that natural thin-film condition without posing a drowning risk.
How to Choose
When deciding how to provide water for a pet spider, the key is to match the method to the species’ natural habitat. For arboreal species (like tree-dwelling tarantulas), misting the enclosure walls provides droplets they can lap, while terrestrial burrowers (like Chilean rose hair tarantulas) do better with a shallow water dish. Always use a dish that’s low enough for the spider to reach without falling in, and add a small stone or piece of cork to give them a way out if they tip over. For tiny spiders like jumping spiders, a wet cotton ball or a bottle cap with a drop of water is safer than a large dish. The most important thing is to monitor your spider—if it’s spending a lot of time at the water source, it’s likely dehydrated, and you should increase humidity or water availability.
Frequently Asked Questions
Q: Can spiders drown in a water dish?
A: Yes, small spiders can drown in deep water. Always use a shallow dish and add pebbles or a sponge to give them a foothold.
Q: How often should I give my pet spider water?
A: Most spiders do fine with a continuous water source that’s replaced every few days. For misting, a light spray every other day is usually enough, but it depends on the species and enclosure humidity.
Q: Do spiders drink from a water bottle?
A: No, they can’t use a bottle. They need a surface with a thin film of water, like a wet leaf, a dish, or a misted wall.
Q: What if my spider hasn’t drunk in weeks?
A: That’s normal for many species, especially if they’re eating regularly. As long as the abdomen isn’t shrunken or wrinkled, they’re likely fine. If you’re concerned, offer a wet cotton ball.
Q: Can I give my spider tap water?
A: Yes, but if your tap water is heavily chlorinated, let it sit out for a day so the chlorine evaporates. Filtered or bottled water is also safe.
Final Thoughts
Spiders have evolved a variety of clever ways to stay hydrated, from lapping droplets to absorbing moisture through their legs. Understanding these methods not only satisfies curiosity but also helps you care for any spider you might keep. Whether you’re a scientist or a hobbyist, the next time you see a spider at a water dish, you’ll know exactly what’s happening—and you can ensure your eight-legged friend always has access to the right kind of water.