Every jumping spider you keep will build a silk hammock. Understanding why they build them — and what they mean — is one of the most useful things you can learn as a new keeper.
💤 What Is a Hammock? #
The sleeping hammock — technically a retreat or sleeping sac — is a silk structure the spider builds at the highest accessible point in its enclosure. It serves as a protected sleeping space, pre-molt chamber, and egg-laying site. Unlike web-building spiders, jumping spiders don’t use silk to catch prey — all their silk is invested in this structure and in the draglines they produce while moving.
🛠️ The Building Process #
A new spider introduced to a fresh enclosure will typically begin hammock construction within 24–48 hours. The spider selects a high anchor point, attaches draglines, and builds outward — creating a dense, layered pocket of silk. This process can take several hours over 1–2 days.
If your spider is slow to build a hammock, try adding a piece of cork bark or an artificial leaf to the upper third of the enclosure. Spiders strongly prefer to build at attachment points rather than directly on mesh.
📚 Reading the Hammock #
The state of the hammock tells you a lot about your spider’s current condition:
A sealed hammock means your spider has sealed itself in for a reason. It’s either molting or brooding eggs. Disturbing it can be fatal. Leave it completely alone until the spider emerges.