Tarantulas
Tarantula on Its Back? Do NOT Touch It! (Molting vs Dead)
Almost every new tarantula keeper has the same jarring moment: you walk past the enclosure and find your spider flipped completely onto its back, legs floating in the air like a dead cockroach. If nobody warned you, the instinct is to panic — and then to open the enclosure and check on it.
Don’t. That’s the first rule of tarantula molting.
What you’re looking at is the most vulnerable moment in a tarantula’s life. If you just found your tarantula in this position, take a deep breath and step away from the enclosure. The Symptom Checker can help if you’re still unsure whether it’s molting or something else.
Why Tarantulas Flip Over
Tarantulas have an exoskeleton, a hard outer shell that supports their body like a suit of armor. The problem is that this suit doesn’t grow with them. To get bigger, they have to shed the entire thing and grow a new one underneath.
This process is called molting, and it’s one of the most vulnerable moments in a tarantula’s life. To get out of their old skin, they need to use gravity to their advantage. By flipping onto their back, they can pump fluid into their body cavity, pop the carapace open like a hatch, and slowly pull their legs, fangs, and even the lining of their stomach out of the old shell.
It takes hours. It looks unnatural. And it’s completely normal.
The Signs That Molting Is Coming
Most tarantulas give you plenty of warning before they flip. If you know what to look for, you won’t be caught by surprise.
The first sign is a change in appetite. Your tarantula will stop eating anywhere from a few days to several weeks before a molt. Some species fast for a month or more. If your normally hungry tarantula suddenly ignores crickets, don’t worry. This is normal pre-molt behavior.
The second sign is the bald spot. New World tarantulas like the curly hair and rose hair species kick urticating hairs off their abdomen when threatened. Before a molt, the bald spot on their abdomen turns dark, almost black. That’s the new skin and new hairs forming underneath.
The third sign is webbing. Many tarantulas spin a thick mat of silk on the ground or across the entrance to their burrow before molting. This gives them a clean surface to lie on and may help them grip the old exoskeleton as they pull free.
If you see all three signs, you can expect a molt within the next week or two.
Molting vs Death Curl
If you’re staring at your tarantula right now trying to figure out if they’re molting or dying, here is how to tell the difference.
A molting tarantula lies on its back or side. The legs are usually relaxed but may twitch or move slowly. If you look closely, you might see the old skin splitting open around the head area. There’s often a silken mat underneath where the spider spun webbing before flipping.
If a tarantula dies outside of molting, it stays right side up with its legs curled inward underneath the body — this is called the death curl. But a tarantula that dies during a molt may also be found on its back. Watch for slow leg movements or skin splitting before concluding it’s dead rather than molting.
| Molting | Death Curl |
|---|---|
| On back or side | Right side up (usually) |
| Legs relaxed or twitching | Legs curled under body |
| Silk mat beneath | No silk mat |
| Skin splitting visible | No skin splitting |
| Slow leg movements | Complete stillness |
If your tarantula is on its back, it’s almost certainly molting. Walk away and check back in a few hours.
Why You Must Leave Them Alone
This is where most people get into trouble. Don’t touch your tarantula while it’s molting.
When a tarantula sheds its exoskeleton, the new body underneath is incredibly soft. It has been described as being like wet tissue paper or soft gelatin. The legs, abdomen, and fangs are all delicate and vulnerable.
If you open the enclosure and nudge the tarantula, you can rupture its abdomen. The tarantula will leak hemolymph, which is their version of blood, and bleed to death. If a cricket or other prey item gets into the enclosure during a molt, it can chew through the tarantula’s soft new skin and kill it.
Never drop food into the enclosure during a molt for this reason. Remove any uneaten prey items. Make sure the water dish is full so humidity stays up. Then close the enclosure and leave it alone.
What Happens After Molting
Once the molt is complete, your tarantula will look incredible. The colors will be brighter, the hairs will be fuller, and the overall size will be noticeably larger. It’s like getting a brand new spider. They will often stretch their legs out, grooming themselves and exploring the enclosure as if testing out their new body.
But don’t rush to handle or feed them. The new exoskeleton needs time to harden. For most species, this takes about 5 to 7 days. During this time, the fangs are still white and soft. Your tarantula can’t eat or defend itself properly. The fangs are hollow, and attempting to bite prey before they harden can permanently deform them.
After about a week, the fangs will turn black and harden. That’s your signal that it’s safe to offer food again. Start with one small cricket and see if they take it. Their appetite will come back quickly, and watching them hunt with their fresh fangs is deeply satisfying.
When to Worry
Most molts go smoothly, but complications can happen. The most common problem is a stuck molt, where the tarantula can’t fully pull a leg or its fangs out of the old skin. This is called dysecdysis. If you see a tarantula stuck mid-molt for more than 12 hours, it may need help, but this is extremely risky for beginners.
Some tarantulas also lose legs during molting. This sounds alarming but is usually not a big deal. Tarantulas can regrow lost legs over subsequent molts. A seven-legged tarantula can live a perfectly normal life until the leg grows back.
If your tarantula emerges from the molt with a bent or twisted leg, that’s often a fluid pressure issue. Most of the time, the leg straightens out on its own within a few days as the exoskeleton dries and the tarantula moves around.
The main thing to watch for after a molt is dehydration. The molting process uses a lot of the tarantula’s fluid reserves. Make sure their water dish is full and that the enclosure humidity is adequate. Some keepers gently drip water onto the mouthparts of recently molted tarantulas to help them rehydrate.
Do Different Species Molt Differently?
Yes. Terrestrial tarantulas like the curly hair, rose hair, and Mexican red knee tend to flip on their backs to molt. Arboreal species like the pink toe tarantula sometimes molt in an upright position, hanging from a web hammock. This can confuse new keepers who expect the classic on-the-back position.
The frequency also varies by age and species. Juvenile tarantulas can molt every few weeks during their growth spurts. Adult tarantulas may only molt once a year or even less frequently. Female tarantulas continue molting throughout their lives, which is why they can live for 20 to 30 years while males live only a few years.
Larger species also take longer to complete a molt. A tiny juvenile sling can shed its skin in under an hour. A full-grown adult Theraphosa blondi, the Goliath birdeater, can spend over 12 hours molting.
Should You Keep the Old Exoskeleton?
The old exoskeleton, called the exuviae, is actually useful. Leave it in the enclosure for the first 24 to 48 hours. Your tarantula may eat parts of it to reclaim moisture and nutrients. After that, remove it to prevent mold growth.
Many keepers keep the exuviae to determine the sex of their tarantula. A mature female tarantula has a distinct sperm receptacle called the spermatheca on the inside of the shed exoskeleton. If you carefully open the old carapace, a vet or experienced keeper can examine the exuviae and tell you the sex. This is the most reliable way to know what you have without waiting for a mature male to develop hooks and bulbs.
The molting process is stressful for tarantulas, but it’s also a sign that they’re healthy and growing. Even experienced keepers still get nervous watching a spider flip over — but they learn to trust the process and let the tarantula do its thing. The tarantula knows what it’s doing.
If you’re patient and resist the urge to intervene, your tarantula will come through the molt just fine. That moment when they crawl out of their old skin and sit next to it like a ghostly twin is one of the coolest things you’ll ever see as a tarantula keeper. It never gets old, no matter how many times you watch it happen.