Why Tarantulas Moult Upside Down (And What to Do About It)

Posted: May 26, 2025

One of the most heart-stopping moments in tarantula keeping is finding your spider flipped on its back. But here’s the truth: it’s probably not dead — it’s just getting ready to moult.

Flipping Over Is Normal

Most tarantulas moult while lying upside down. This position gives them the leverage they need to push free from their old exoskeleton. Think of it as nature’s moulting mat — weird-looking, but efficient.

Signs It’s a Moult (Not a Crisis)

• They stopped eating days or weeks ago
• You see a thin silk mat beneath them
• The legs are outstretched, not curled tightly under (a death curl)
• No signs of damage or fluids

What You Should NOT Do

Don’t touch them. Don’t flip them. Don’t spray them. It’s tempting to act — but most moult-related fatalities happen due to human interference.

Do This Instead:

• Keep the room quiet and vibration-free
• Ensure humidity is within species range
• Check that a clean water dish is available
• Wait — a successful moult can take hours

Want to Be Proactive?

MoultMend was developed by keepers who’ve faced the fear and loss of failed moults. It’s designed to support hydration and internal recovery before and after this crucial process.

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