Ever found your tarantula lying motionless on its back and feared the worst? That’s not death—it’s life in progress!
Tarantulas must shed their entire exoskeleton to grow, a vulnerable process called molting that happens throughout their 15-30 year lifespan.
Recognizing the warning signs of an upcoming molt is crucial for keeping your eight-legged companion safe during this critical transformation.
If your tarantula spins a special web mat before lying still, it is likely positioning itself for preparing your tarantula for molting
Primary Visual Signs Your Tarantula is Preparing to Molt
Darkening of the Abdomen
The most reliable sign (95%) is a dark abdomen. This happens 1-3 weeks before molting. The darkness comes from the new exoskeleton forming under the old one, kind of like wearing a new shirt under an old one before making the big reveal.
“When a tarantula’s abdomen turns darker, it’s almost certain they’re preparing to molt,” says Dr. Amanda Rodriguez, arachnid specialist. “This is especially easy to see in lighter-colored species like the Grammostola pulchra.”
My Chilean Rose Hair, Rosie, always looks like she’s been rolling in chimney soot when she’s ready to molt. It’s her way of saying, “Hey human, I’m about to do something spectacular—don’t mess it up!”
Bald Spot Development on Abdomen
About 85% of tarantulas show a bald spot on their abdomen before molting. This happens because:
- Hair loss from using urticating hairs for defense (their version of pepper spray!)
- Natural hair dropping as part of molt preparation
- Thinning of the exoskeleton
This sign appears 2-8 weeks before molting and is more common in New World tarantulas from North and South America. My friend’s Mexican Red Knee looked like he was developing a spider version of male pattern baldness right before his last molt!
Physical Body Changes
Look for these physical changes:
- Dull body color (70% reliable) – like they’ve been hitting the spider gym too hard
- Tight or shiny abdomen (65% reliable) – picture a balloon about to pop
- Split line forming where the old exoskeleton will break
Behavioral Signs That Indicate an Imminent Molt
Reduced or Stopped Feeding
About 90% of tarantulas stop eating 2-4 weeks before molting. Remove uneaten food within 24 hours. Leaving prey animals in the enclosure can stress or harm your molting tarantula.
It’s like their version of “I’m too nervous to eat before the big day!” Just like I can’t eat before a job interview, they’re prepping for their big transformation.
| Tarantula Stage | Fasting Period |
|---|---|
| Spiderling | 1-2 weeks |
| Juvenile | 2-3 weeks |
| Adult | 3-6 weeks |
Decreased Activity and Movement
Your normally active spider may become very still before molting. This lethargy happens in about 80% of tarantulas 1-4 weeks before molting. Don’t mistake this for illness.
“A pre-molt tarantula conserves energy for the difficult process ahead,” explains Tom Watson, owner of Arachnid Adventures. “This decrease in activity is a natural part of their growth cycle.”
Last month, my normally busy Curly Hair tarantula, Fred, was so still I started wondering if he was practicing to be a statue for Halloween. Turns out he was just gathering his strength for the big shed!
Web Spinning and Habitat Modification
About 75% of tarantulas create a special web called a molt mat 1-7 days before molting. This silky platform gives them a safe, clean surface for the molting process. It’s their version of laying down fresh sheets before a big event!
Different genera show different webbing behaviors:
- Terrestrial tarantulas (like Brachypelma) make flat web mats – think of it as their personal yoga mat
- Arboreal tarantulas (like Avicularia) create silk hammocks or barriers – fancy spider hammocks!
- Burrowing species may close off their burrow entrances – putting up the “Do Not Disturb” sign
Advanced Pre-Molt Signs (Final 24-48 Hours)
Positioning for Molt
The most definitive sign (99% reliable) is when your tarantula lies on its back or side. This happens 0-24 hours before the actual molt begins. The first time I saw this, I thought Rosie was practicing her spider yoga. Turns out she was just getting ready for the big flip!
IMPORTANT: Never disturb a tarantula in this position! Moving them can cause death or serious injury. That’s like someone waking you up mid-surgery—not a good idea!
Final Physical Changes
Just before molting starts, you might see:
- Visible separation of the old exoskeleton
- Slight leg trembling (spider jitters!)
- The beginning of a split along the carapace
Creating Optimal Conditions for a Successful Molt
For a safe molt, maintain these conditions:
| Factor | Optimal Range |
|---|---|
| Humidity | 65-75% (varies by species) |
| Temperature | 75-82°F (24-28°C) |
| Enclosure Space | At least 3x the spider’s leg span |
| Substrate Moisture | Slightly damp to touch |
Keep a full water dish in the enclosure. Good hemolymph pressure helps tarantulas push out of their old exoskeleton. It’s like how we need to stay hydrated before a workout, only their workout is escaping their entire body!
What to Do (and NOT Do) When You See Molt Signs
Proper Care During Pre-Molt
DO:
- Maintain proper humidity
- Ensure a full water dish
- Observe from a distance (like you’re watching a Broadway show—enjoy, but don’t interact!)
DON’T:
- Handle your tarantula (would you want someone picking you up while you’re trying to wiggle out of your skin?)
- Make loud noises near the enclosure (no spider rave parties during molt time)
- Attempt to feed your tarantula
- Disturb the spider in any way
Post-Molt Care and Recovery
Immediate Post-Molt Period
After molting, your tarantula’s new exoskeleton is soft and vulnerable. The hardening timeline varies:
- Exoskeleton: 2-5 days
- Fangs and chelicerae: 7-14 days
- Full color development: 2-3 weeks
Don’t feed your tarantula until its fangs have hardened completely (7-14 days). Offering food too soon can damage their fangs. That’s like trying to eat a steak with baby teeth—it just doesn’t work!
Examining the Shed Exoskeleton
The discarded exoskeleton (called exuviae) can tell you a lot:
- Gender (by checking the epigastric furrow)
- Health status
- Growth progress
You can keep the molt as a record of your tarantula’s growth. Many enthusiasts collect and preserve these molts. I have all of Rosie’s molts lined up on a shelf—it’s like having baby photos, but spidery!
Common Molting Complications
Sometimes molts don’t go perfectly. Watch for these problems:
- Stuck exoskeleton (5% of molts) – like getting stuck halfway through taking off a tight sweater
- Limb loss (8% of molts) – don’t worry too much, they grow back! (If only humans could do that…)
- Fang deformities (3% of molts)
If your tarantula has a stuck molt, you can find help at The Tarantula Forum where expert keepers share advice on emergency interventions.
According to Tom Moran of Tom’s Big Spiders, “Most molting issues stem from improper humidity or disturbance during the process. Prevention is always better than trying to fix a molt gone wrong.”
Remember that molting is a natural process for your Theraphosidae pet. With proper care and a stress-free environment, your tarantula will successfully shed its old exoskeleton and grow into a bigger, often more colorful spider.
It reminds me of the current trend of “glow-ups” you see all over TikTok—tarantulas were doing impressive transformations long before social media made it cool!
