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Will a spider drown?

Spiders are air-breathing animals that rely on their book lungs and tracheal system to take in oxygen and get rid of carbon dioxide. Since spiders don’t have gills like fish, they cannot extract oxygen from water and will eventually drown if submerged for too long.

Can spiders swim?

Most spiders cannot swim. Their bodies are not equipped for swimming or being underwater. Their legs are designed for walking, climbing, and jumping on land surfaces. When on the water’s surface, spiders rely on surface tension to stay afloat. They can walk or skim along the surface but cannot propel themselves through water.

Spider species that can swim

While most spiders cannot swim, there are a few exceptions:

  • Fishing spiders – Species like the raft spider have specialized hairs on their legs that help repel water, allowing them to stay on the surface.
  • Diving bell spiders – Build underwater bubbles of air to breathe from while hunting prey underwater.
  • Water spiders – Use a silken web to trap air bubbles and breathe from underwater.

Even in these species adapted for aquatic environments, the spiders cannot indefinitely stay submerged and will eventually need to return to the surface for air.

How long can a spider hold its breath?

Most spiders can only survive a few hours at most when fully submerged in water. Their oxygen demands are high due to their active lifestyle. Researchers estimate that most spider species will drown within the following timeframes when submerged:

Spider size Approximate drowning timeframe
Small spider (body size 2-4 hours
Medium spider (body size 0.5 – 1 in) 4-6 hours
Large spider (body size >1 in) 6-12 hours

Variables like the spider’s activity level, temperature, and dissolved oxygen in the water can affect these timeframes. But generally, most healthy spiders cannot survive longer than 12 hours fully submerged due to drowning.

Tracheal systems are not designed for underwater breathing

A spider’s tracheal breathing system is designed to take in oxygen from the air, not water. Their book lungs have openings that connect to the outside air. When submerged, water presses on the openings, making it impossible for the spider to take in oxygen.

Do spiders have defenses against drowning?

Spiders have some behavioral adaptations that can delay drowning:

  • Trapping air bubbles – Diving bell spiders and some other species carry air bubbles underwater.
  • Using silk to float – Some spiders can trap air in their silk to stay above water temporarily.
  • Climbing out quickly – Most spiders will immediately move to dry land if dropped in water.
  • Playing dead – Some spiders employ thanatosis, or pretending to be dead, until they can get to dry land again.

However, none of these behaviors can prevent drowning indefinitely. The spiders still require air to breathe.

Physiological adaptations to prevent drowning

True spiders lack physiological adaptations for underwater breathing and gas exchange like:

  • Gills to extract oxygen from water
  • An ability to close off their book lungs when submerged
  • High hemolymph oxygen storage capacity

Without gills or other specialized breathing adaptations, spiders simply do not have a way to get air if immersed for extended periods.

Do female spiders carry egg sacs to prevent drowning?

Female spiders producing an egg sac will often carry the egg sac in their chelicerae (mouth parts) or attach it to their spinnerets. This helps them protect the eggs until they hatch.

Carrying an egg sac does not prevent the female spider from drowning. Having an attached egg sac makes swimming and climbing out of water more challenging. A female spider carrying eggs is likely to succumb to drowning even faster than a spider without an egg sac.

Egg sacs designs for land, not water

Spider egg sacs are designed to keep the eggs:

  • Warm and moist on land
  • Safe from predators/parasites
  • Suitable for hatching spiderlings

The silk egg sacs provide protection in terrestrial, not aquatic, environments. Attaching an egg sac does not confer any advantage to the mother spider if she falls into water.

Do any spiders live underwater?

No species of true spiders have adapted to live permanently underwater. All spiders have an anatomy adapted to breathe air.

Some spiders can make short dives, construct underwater bubbles, or live near the water’s edge. But there are no known spiders that spend their entire life cycle submerged.

Semi-aquatic spiders

These spiders have some adaptations that allow temporary operation underwater:

  • Diving bell spiders
  • Fishing spiders
  • Raft spiders
  • Water spiders

But they still do not have the gills, oxygen storage capacity, or underwater breathing abilities to live wholly submerged like aquatic insects or crustaceans.

Do spiders intentionally jump into pools and sinks?

There is no evidence spiders intentionally jump into sinks, pools, or bodies of water. Spiders ending up in water is usually accidental.

Reasons spiders may fall into water:

  • Falling off an overhanging tree branch
  • Getting washed off a surface by rain or sprinklers
  • Plummeting into water due to their ballooning behavior
  • Falling downsink and bathtub drains accidentally

With their vulnerability to drowning, spiders actively avoid bodies of water and quickly escape if they fall in.

Myths about spiders jumping into water

There are some myths that spiders intentionally jump into water for supposed benefits like:

  • Using water to drink or absorb through their exoskeleton – Spiders get moisture from prey and habitat, not pools/sinking.
  • Cooling off their bodies – Jumping into water would dangerously risk drowning.
  • Laying underwater eggs – No spiders lay eggs underwater.

These myths are not based on spider biology or behavior. Spiders lack adaptations for voluntary underwater activities.

Do spiders survive when rinsed down drains?

Spiders washed down bathroom or kitchen sinks and drains have a very low chance of survival. Drain systems are designed to carry water, not air-breathing spiders.

Hazards spiders face when washed down drains:

  • Drowning – Drains fill with water, leaving no air.
  • Physical damage from water pressure and debris
  • Lack of food/web anchoring points if they reach sewage systems

While it’s possible a spider might be washed into a temporary air pocket, the overall likelihood of surviving a trip down drains and pipes is extremely low.

Can spiders clog or infest drain pipes?

Due to their small size, spiders are very unlikely to clog drain pipes. They can pass through most household drain systems without issue.

Spiders also cannot establish or reproduce populations inside plumbing systems. The lack of food, light, and proper habitat makes drain pipes an unsuitable environment to infest.

Will a spider dry out or survive after being underwater?

If a spider is pulled from water quickly, it has a chance to recover by drying itself off. But its survival depends on several factors:

  • Time submerged – The shorter time underwater, the higher chance of surviving.
  • Spider health – Age, recent feeding, and injuries impact recovery.
  • Drying method – Gently drying with a cloth aids recovery vs. shaking off wet spiders.

With quick rescue and proper drying, healthy spiders can fully recover after short periods of submersion. But extended time underwater will likely be fatal.

Steps for drying a wet spider

To dry a mildly wet spider:

  • Scoop or collect the spider gently using a container or cloth.
  • Do not shake the spider – this may injure it.
  • Place the spider on a dry cloth or paper towel.
  • Gently dab or blot the spider’s body and legs to absorb water.
  • Allow the spider to finish self-drying as well.

With proper drying, resuscitated spiders may fully recover from short-term water exposure.


In summary, spiders cannot survive prolonged periods underwater due to drowning. While a few species have adaptations like air bubbles for temporary water exposure, all spiders fundamentally require air to breathe. Spiders do not intentionally jump into water and have low survival rates if washed into sinks or drains. With human intervention, quick drying after mild water exposure can allow some spiders to recover and survive.