🕷️ Reading a tarantula

Is My Tarantula Stressed?

They do signal. The signals are just quieter than most people expect.

The actual warning signs

• Threat posture — front legs and pedipalps raised high, fangs exposed. This is unambiguous: back away and close the enclosure.
• Hair flicking — New World species rub their abdomen with the back legs, releasing urticating hairs. These are genuinely irritating to skin and dangerous near eyes. A bald patch on the abdomen means a spider that has been flicking.
• Rapid retreat or frantic running when disturbed.
• Striking at the enclosure or at tongs.
• Persistent glass climbing — often a sign the substrate or humidity is wrong, or that the enclosure is too small or too open for a burrowing species.

Respect the threat posture. Tarantula venom is not usually medically significant for most commonly kept species, but a bite hurts, Old World species are considerably more defensive and have stronger venom, and a dropped spider can be fatally injured — their abdomens rupture easily from quite short falls.

What is normal and worries people anyway

Not eating. Tarantulas routinely fast — for weeks, and in large adults sometimes months. It is normal, particularly before a moult. A spider with a plump abdomen that is not eating is fine.

Sitting motionless for days. Entirely normal. Tarantulas are ambush predators and energy conservation is the default state.

Lying on its back. This alarms every new keeper and it is almost always pre-moult. Do not disturb a spider on its back and do not attempt to right it — moulting is the most vulnerable period in a tarantula's life and interference can kill it.

Webbing everywhere, or sealing itself into a burrow. Normal, and often pre-moult.

A bald patch on the abdomen. Usually from hair flicking, and it fills back in at the next moult.

What actually indicates a problem

The death curl — legs curled tightly underneath the body, the spider hunched. This is a dying or severely dehydrated spider, not a resting one. The immediate action is to ensure a shallow water dish is available and raise humidity; it is often linked to dehydration and is sometimes recoverable if caught early.

Distinguish it carefully from a moulting spider, which lies on its back with legs relatively extended. Back = moulting, leave alone. Curled underneath = emergency.

A shrivelled abdomen indicates dehydration or long-term under-feeding.

Fluid leaking from a joint is a rupture and is usually fatal, though sealing it with cornflour or superglue is sometimes attempted.

Lethargy with an unsteady gait can indicate poisoning — commonly from insecticide residues, including flea treatments used on pets in the same room, which are extremely toxic to invertebrates.

Reducing stress in the first place

Most of it is husbandry and restraint. Get the species-specific requirements right — terrestrial, arboreal and fossorial species need quite different setups, and humidity requirements vary enormously.

Provide a proper hide and enough substrate depth for burrowing species; a spider with nowhere to retreat to is a stressed spider. Keep the enclosure somewhere without constant vibration.

And handle as little as possible. There is no evidence that tarantulas benefit from or enjoy handling, and the risk is entirely one-sided: a fall from your hands can kill the animal. Most experienced keepers have largely stopped handling, and move spiders with a catch cup rather than hands.

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