Millipedes burrow for shelter, moisture, feeding and moulting, so hidden behaviour is usually normal rather than a problem. Many species live in soil, leaf litter and decaying wood, where moving below the surface is part of everyday life.

Why millipedes burrow

Millipedes are detritivores, which means they live on and around decaying organic material. In the wild, that usually means the forest floor, where fallen leaves, rotting wood and damp soil create a natural place to feed and hide. Burrowing lets them stay in the moist lower layers of the substrate, move through softened material and avoid unnecessary disturbance.

Burrowing is also important when millipedes moult. This is a vulnerable time, so many species retreat below the surface to shed their old covering in a more protected space. If a millipede disappears for a while after feeding and behaving normally, moulting is one likely explanation.

If you want broader behaviour context, our Millipede Behaviour, Biology & Handling Guide is a useful place to start.

What burrowing means

A millipede spending most of its time underground is often behaving naturally. Some species are less visible than others, and some individuals emerge more often than others. That variation is normal. A keeper only needs to look closer if the animal is unusually buried and not feeding, if the substrate is very dry, or if the enclosure smells off.

For troubleshooting, see Why Is My Millipede Always Buried?.

Useful context

Burrowing is easiest in a deep, loose substrate with plenty of leaf litter and decomposing material mixed through it. Millipedes burrow into their habitat, not just into bedding, so the enclosure needs to offer both shelter and food at the same time. Moisture matters too: the substrate should stay damp and breathable, not dry, compacted or waterlogged.

Newly introduced millipedes may also burrow while they settle in. Giving them a calm enclosure and leaving them undisturbed is usually better than digging them up to check on them. In most cases, a hidden millipede is simply using the enclosure as it should.