It is 11pm. You walked past your jumping spider’s enclosure and noticed she is hanging upside down, completely still, legs curled in toward her body. Your first thought was the worst thought.
Stop. She is almost certainly molting, and right now the single best thing you can do is close the lid and walk away.
This guide explains everything that is happening inside that enclosure, what the full process looks like phase by phase, and the specific situations where you actually do need to act.
Key Takeaways
- An upside-down, motionless jumping spider sealed inside its hammock is almost always molting, not dying. Leave it completely alone.
- Remove all live prey from the enclosure the moment you see pre-molt signs. A cricket can kill a molting spider.
- The active molt (ecdysis) takes 20 minutes to 3 hours depending on life stage. Post-molt hardening takes 5 to 10 days.
- Do not feed for 5 to 7 days after the molt. Do not handle until the spider has eaten its first post-molt meal.
- Mist one enclosure wall lightly once per day during pre-molt to keep humidity adequate. Never soak the whole enclosure.
- Three warning signs that require action: the spider has been partially out of its old skin for more than 4 hours with no progress; it has fallen out of its hammock mid-molt; or it remains completely motionless for 72 or more hours with no hammock and no shed skin visible.
- Dysecdysis (a stuck or failed molt) is most often caused by low humidity and dehydration. The best prevention is consistent misting before the molt starts.
What Is Jumping Spider Molting?
Molting (ecdysis) is the only way a jumping spider can grow. Their rigid exoskeleton cannot stretch, so every few weeks the spider grows a new, larger skin underneath the old one, then sheds the outer shell. The shed skin is called the exuvia. Each molt advances the spider one instar: a growth stage closer to adulthood.
Each molt moves your spider forward one instar. Think of an instar as a growth stage. Most jumping spiders complete 7 to 10 instars over their lifetime, with juveniles cycling through early instars quickly and the final instars taking much longer. Phidippus regius (the regal jumping spider) typically reaches maturity after 8 to 9 instars. For species-specific molt patterns, see the Phidippus regius care guide.
One thing that surprises new keepers: molting can regenerate a lost limb. A leg that was dropped after a cricket bite or an accident can partially regrow over the next one or two molts.
How Often Do Jumping Spiders Molt?
Molt frequency changes dramatically across the spider’s life. Spiderlings shed every few weeks. Sub-adults molt every one to three months. Mature adults may go four to six months between molts, or stop molting entirely after the terminal adult molt.
| Life Stage | Molt Frequency | Notes |
|---|---|---|
| Spiderling (instars 1 to 3) | Every 2 to 4 weeks | Rapid early growth |
| Juvenile (instars 4 to 6) | Every 4 to 8 weeks | Slowing noticeably |
| Sub-adult (instars 7 to 8) | Every 6 to 12 weeks | Pre-adult preparation |
| Adult female | Every 3 to 6 months (if at all) | Some females continue molting; terminal molt varies by species |
| Adult male | Terminal molt ends growth | Males rarely molt after reaching maturity |
Tracking your spider’s molt dates is one of the most useful habits you can build. Knowing your spider last molted six weeks ago tells you a lot when it goes off food again.
Pre-Molt Signs to Watch For
The clearest sign your spider is entering pre-molt is a sudden, total loss of interest in food. This can happen 3 to 14 days before the actual shed. Your spider is not ill. It is redirecting all of its energy toward building the new exoskeleton underneath the old one.
Other pre-molt signs, roughly in the order you will notice them:
- Refuses prey: ignores or backs away from insects it normally attacks instantly
- Less active, more reclusive: stays near or inside its hammock instead of exploring
- Color appears darker or duller: the new skin beneath creates a slightly different light-passing effect through the old cuticle
- Seals the hammock entrance: spins extra silk to close the door; this is the most reliable single signal
- Abdomen may look shrunken: fluid shifts internally as the new cuticle forms
The sealed hammock stage is the point where most keepers panic. A spider that has webbed itself in and has not moved for 24 to 48 hours is not in trouble. It is exactly where it needs to be.
What to do during pre-molt:
- Remove every live feeder insect immediately. This is non-negotiable. A cricket inside the enclosure during a molt is a genuine danger.
- Mist one side wall of the enclosure lightly once per day. Humidity helps the old exoskeleton flex and release cleanly.
- Do not handle the spider.
- Do not tap the enclosure, shine a bright light directly on the hammock, or make loud noises nearby.
If your spider has stopped eating and you are wondering whether something else is going on, the jumping spider not eating guide walks through non-molt reasons for food refusal as well.
The 5 Phases of the Molt
The active molt is not a single moment. It unfolds in five distinct phases, each with its own visual cues. Understanding them helps you tell normal from concerning.
Phase 1: Positioning
Your spider moves to its sealed hammock, orients upside down, and becomes very still. The legs may already be slightly pulled in toward the body. This is the start of the process, not the end of it.
Phase 2: Exoskeleton Split
The old cuticle splits, usually along the carapace (the hard upper shell behind the head). You may be able to see a thin line appear across the top of the spider’s body. This is the moment ecdysis has officially begun.
Phase 3: Extraction
This is the physically demanding stage. The spider pushes and pulls itself out of the old shell using rhythmic leg movements and hemolymph pressure. It looks effortful and uncomfortable. It is. This phase lasts the longest and is where stuck-molt risk is highest if humidity is low.
Phase 4: Expansion
Free of the old skin, the spider hangs still or curls its legs in tightly (the “death curl”). Do not panic. The spider is pumping hemolymph through the new exoskeleton to expand it to the correct size before it hardens. This can look identical to a dead spider.
Phase 5: Hardening (Sclerotization)
Over the next 5 to 10 days, the new cuticle hardens and darkens. The fangs (chelicerae) are the last structures to fully sclerotize, which is why you wait until the spider’s jaws are back to their normal dark color before offering food.
The Molt Stage Timeline
Use this table as a reference during the process. Timing varies by age and health. Slings move faster, mature adults slower.
| Stage | What You’ll See | Typical Duration |
|---|---|---|
| Pre-molt (early) | Reduced appetite, less active, spends more time in hammock | 3 to 14 days before shed |
| Pre-molt (late) | Hammock sealed, spider invisible or motionless inside | 24 to 72 hours before shed |
| Active molt (ecdysis) | Spider upside down, legs pushing out of old skin; old skin may be visibly splitting | 20 min to 3 hours |
| Post-molt (soft) | Spider free of old skin, body pale or translucent, “death curl” position, very still | 2 to 6 hours |
| Post-molt (hardening) | Spider moves back to normal position, colors deepen gradually | 24 to 72 hours |
| Cuticle fully hardened | Fangs are dark again, spider is active and alert | 5 to 10 days post-shed |
| Ready to feed | Spider shows interest in prey | 5 to 7 days post-shed |
How Long Does Jumping Spider Molting Take?
The active molt (ecdysis) takes 20 minutes to 3 hours depending on life stage. Spiderlings shed in under 30 minutes. Mature adults, especially female Phidippus regius, can take up to 3 hours. Full recovery from the first pre-molt signs to a hardened, feeding-ready exoskeleton spans 2 to 4 weeks.
What to Do During the Actual Molt
The correct action during the active molt is nothing.
Once ecdysis has started (you can sometimes see the old skin splitting along the carapace), any disturbance can cause the spider to thrash, break a leg, or rupture the new exoskeleton.
Close the enclosure. Put your phone down. Do not pick up the enclosure to get a better look. If you want to observe, do it from a distance and keep the room lighting normal. Sudden bright light causes stress.
After the spider has been free of its old skin for 2 to 3 hours and has uncurled but is still pale and soft:
- You can look, but still do not open the enclosure.
- Do not attempt to remove the exuvia (shed skin) yet.
- Keep humidity consistent with a light wall mist if you normally mist daily.
After 24 hours, the spider should be moving around normally even if still pale. After 5 to 7 days, the cuticle will have hardened enough that you can offer a small prey item. Wait until the spider has eaten before resuming any handling.
For guidance on sizing prey correctly at different life stages, see what jumping spiders eat.
Post-Molt Recovery: Normal vs. Concerning
During the first week after a molt, everything looks slightly off and that is fine:
- Pale or translucent coloring: the new cuticle takes several days to fully pigment
- Smaller-looking abdomen: common; resume feeding schedule and it will round out
- Soft, slightly wobbly movement: normal until cuticle fully hardens
- Staying in or near hammock: still resting; do not disturb
- Exuvia visible: the shed skin often stays in the hammock; leave it, the spider may use it for structural support
Do not feed during this window. Even a small fruit fly can injure a spider whose fangs have not yet hardened. The spider’s jaws need to be dark, back to their normal color, before you offer food.
For context on how appetite patterns shift around molts, see jumping spider not eating.
Dysecdysis: When a Molt Goes Wrong
Dysecdysis is an incomplete or failed molt: the spider cannot fully extract itself from the old exoskeleton. It is one of the most serious conditions in captive jumping spiders, and it is almost always caused by insufficient humidity or dehydration going into the molt.
Is This Dysecdysis? Use This Checklist
Go through each question in order:
- Has the spider been partially visible outside its hammock and stuck in the same position for more than 4 hours?
- Can you see the old skin still attached to one or more legs while the body has emerged?
- Has the spider fallen out of its hammock during the molt?
- Is the spider fully encased in old cuticle with no movement for 24 or more hours, and you can confirm no shed skin has appeared?
If you answered yes to any of these, you are likely dealing with a problem molt. Here is what to do, in order:
- Raise humidity immediately. Add a moist paper towel to a corner of the enclosure or lightly mist three walls. Your target is 75 to 85% relative humidity: damp air, not standing water.
- Do not try to pull the old skin off with your fingers. You will tear off legs.
- Wait 2 to 3 hours after the humidity boost to see if the spider progresses on its own.
- If no progress after 4 to 6 total hours: You can try dampening a cotton swab in lukewarm water and very gently touching it to the stuck exoskeleton where it meets the new skin. The goal is to loosen the seal, not to pull.
- If the spider is still stuck after 12 hours: Contact an exotic vet experienced with invertebrates. Some vets can assist with stuck molt removal under magnification.
The single best way to prevent dysecdysis is consistent misting in the days before the molt. If you find your spider in pre-molt and the enclosure feels dry, start misting now. For a complete humidity and care routine, the jumping spider care guide covers all environmental parameters.
The Three Warning Signs That Require Action
Most “my spider isn’t moving” moments are completely normal. Three specific situations warrant concern:
1. Stuck in the shed for more than 4 hours with no progress. If part of the spider has emerged but it has completely stopped moving with old skin still attached, treat this as potential dysecdysis (see above).
2. The spider has fallen out of its hammock during the molt. Molting mid-air without the structural support of the hammock is dangerous. If your spider has fallen and is on the enclosure floor mid-molt, gently place a moist paper towel or piece of cork bark beneath it for support, add humidity, and watch closely. Do not attempt to move the spider while it is actively molting.
3. Motionless for 72 or more hours with no hammock, no shed skin, and no pre-molt signs you recognized. This could indicate the spider died before the molt began, possibly from dehydration, an underlying illness, or a feeder injury. Gently nudge a leg with a soft brush. If there is no response at all and the abdomen is shrivelled, the spider may have passed. If there is any response, treat it as late pre-molt and follow the humidity and no-feeding protocol.
How to Prevent Molt Problems
A healthy molt starts weeks before the shed. These habits reduce risk significantly:
- Mist one enclosure wall every 2 to 3 days as a baseline, increasing slightly during pre-molt. Never mist so heavily that there is standing water.
- Remove all feeders within 24 hours if the spider ignores them. Do not leave insects in the enclosure overnight.
- Keep temperatures in the 24 to 28 C (75 to 82 F) range. Temperatures outside this range slow the hardening process.
- Do not handle in the two weeks following a molt. The new cuticle is still vulnerable. See the handling guide for when it is safe to resume.
- Track molt dates. Knowing your spider molted six weeks ago tells you a lot when it goes off food again.
After the Molt: First Feeding and Return to Normal
The moment you know the molt is fully successful: your spider hunts and kills a prey item on its own. That first strike confirms the fangs have hardened and the new exoskeleton is functional.
Start small: offer prey no longer than half the spider’s body length. If the spider refuses, wait another two days and try again. Some spiders take 10 to 14 days to show hunting interest after a difficult molt. As long as the spider is active and alert, this is within normal range.
Once the spider has eaten, you can resume normal handling, cleaning, and feeding schedules. The exuvia in the hammock can be removed at the next routine clean, or you can leave it. Your spider won’t mind either way.
Frequently Asked Questions
Is my jumping spider dead or molting?
If your spider is hanging upside down in or near its hammock and has recently shown pre-molt signs (stopped eating, sealed the retreat, darker coloring), it is almost certainly molting. A dead spider typically falls to the enclosure floor, has a severely shrivelled abdomen, and will have been unresponsive for more than 72 hours with no hammock and no shed skin present. Gently nudge a leg with a soft brush: any response at all, even a tiny twitch, means the spider is alive.
How long does a jumping spider stay in its hammock during molting?
The sealed-hammock phase typically lasts 24 to 72 hours before the active molt begins. After the molt, many spiders remain in or near the hammock for another 2 to 5 days while the new cuticle hardens. The entire process from sealed hammock to first feeding can take 1 to 2 weeks. Do not disturb the hammock during this entire window.
What should I do if my jumping spider is molting upside down?
Nothing. Upside-down is the correct molting position for jumping spiders. The spider uses gravity and leg movements to push itself out of the old exoskeleton. Interfering with this position, even to “help,” can interrupt the extraction process and cause a stuck molt. Close the enclosure and let the spider finish.
How do I know when the molt is complete?
The molt is complete when the spider has fully separated from the old exoskeleton (the exuvia), returned to an upright or resting position, and begins moving around the enclosure normally over the next 24 to 48 hours. The exuvia will be visible as a small, translucent shell, often still attached to the hammock. You are ready to offer food when the spider’s chelicerae (jaws) have returned to their normal dark color.
Why did my jumping spider stop eating before molting?
Before a molt, the spider redirects all of its metabolic energy into building the new exoskeleton underneath the old one. Hunting requires hemolymph pressure and physical exertion that is both difficult and risky during this window. The fast is not a problem: it is biology working exactly as it should. Most pre-molt fasts last 1 to 3 weeks and resolve completely once the molt is done and the new exoskeleton has hardened.
Can I feed my jumping spider right after molting?
No. Wait at least 5 to 7 days after the molt before offering food, and wait until the chelicerae (jaws) have returned to their normal dark color. The fangs are the last part of the exoskeleton to fully harden, and a spider that tries to bite prey with soft fangs can injure itself. Start with small, soft prey for the first post-molt meal.
Jumping spiders molt throughout their entire lives, and watching it happen, even when it goes smoothly, never entirely stops feeling dramatic. Every shed is your spider arriving in a slightly larger version of itself. The best thing you can do every single time is the same: pull the prey, mist the wall, and trust the process.