Giant Millipede Enrichment: The Substrate Is the Food and the Home

Almost every guide in this series eventually says the substrate matters. For a millipede it is very nearly the entire enclosure.

What the Research Says

Nothing on millipedes. The borrow is from the tarantula housing study, covered in full in our Tarantula enrichment guide.

Tarantulas in an enclosure roughly six times larger with six times as much structure used 77 percent larger home ranges and showed 150 percent greater odds of being active in a novel environment, while being no more active overall and showing no preference between the two.

A detritivorous myriapod and an ambush-hunting spider have almost nothing in common. What carries over is the caution: an invertebrate that spends its time buried and slow is not obviously suffering from a lack of stimulation, and the useful work here is husbandry, not novelty.

Deep, Decaying Substrate

The whole guide in one section. Millipede substrate mix is the convenient version. A large enclosure takes considerably more than one pack.

Add rotting hardwood and pesticide-free leaf litter on top of it. Rotting is the key word: fresh wood has no food value to a detritivore, and this is not decoration on top of a base, it is the diet.

Deep enough to bury completely. They burrow to molt and spend much of their time under the surface, and shallow substrate removes most of what a millipede does.

Never garden soil, which may carry pesticides, fertilizer or parasites.

Humidity Held in the Substrate

Consistently damp and never wet, with the substrate itself doing most of the buffering. A fine mist spray bottle tops it up, and deep substrate holds it far better than misting a shallow layer ever will.

Ventilation still matters. Stagnant damp brings mold and mites, and clearing a mite bloom out of a millipede enclosure is a genuine nuisance.

Calcium

Easy to skip and it shows up at the worst moment. Millipedes need calcium for the exoskeleton, and deficiency surfaces during molts, when the animal is already at its most vulnerable.

A cuttlebone left on the substrate is the standard method. Crushed eggshell works as well. What a failed molt looks like across pet invertebrates is the shape the deficiency eventually takes.

Food Variety, Modestly

Substrate does the bulk of it. Beyond that, small amounts of fresh vegetables and fruit scattered on the surface give variety and a reason to come up.

Scatter it instead of piling it in one place, and remove what is not taken before it molds. Keep it a supplement: a millipede fed mostly on fruit rather than decaying wood is being fed the interesting part instead of the nutritious part.

A Group

They are not predatory or territorial and are commonly kept in groups. Space and substrate volume are the only real constraints.

Avoid mixing species, which is a mite and parasite transfer question and not a compatibility one.

Leave Them Buried

Worth listing. Millipedes molt underground and a disturbed molt is a dangerous one. Resist digging to check on an animal that has gone quiet, and give it weeks rather than days.

Priority Order

1. Deep substrate of decaying hardwood and leaf litter
2. Consistent damp held in the substrate, with ventilation
3. A permanent calcium source
4. Enclosure floor area over height
5. Occasional scattered fresh produce as a supplement
6. A group, if you want one
7. Not digging them up

What Not to Do

Do not use shallow substrate. Do not use fresh wood, which a detritivore cannot use. Do not use garden soil. Do not seal the enclosure to hold humidity. Do not feed mostly fruit. Do not dig up a buried millipede that may be molting. And wash your hands afterwards, since many species secrete defensive chemicals that stain skin and irritate eyes.

Sources & Further Reading