Archispirostreptus gigas

About Archispirostreptus gigas

This species is one of the largest millipedes commonly kept in the hobby, native to East Africa. Adults can reach up to 33 cm in length and live for 5–7 years under good care. They're jet black with reddish-brown legs and a smooth, cylindrical body.

Despite their size, they are generally docile. They have no venom and do not bite, though their defensive secretions can stain skin and irritate eyes, so wash hands after handling. Their defence is to curl tightly and, if very stressed, release secretions from their glands. They make great display animals and tolerate gentle handling well once settled.

Enclosure

They need a genuinely large enclosure. For a single adult, a minimum of 60×40×40 cm is recommended. Bigger is always better. For a pair or small group, 90×45×45 cm gives them proper room to explore and establish territories.

Use a glass or PVC terrarium with side ventilation rather than a fully mesh lid, as this helps maintain the high humidity they require. A tight-fitting lid is important. They are surprisingly capable of pushing against loosely fitted lids.

Substrate & humidity

The substrate is what matters most for A. gigas. They need a very deep, very moist, nutrient-rich mix:

• 50% well-rotted deciduous wood (the primary food source)
• 30% coco coir (moisture retention)
• 20% organic topsoil or leaf mould
• Substrate depth of at least 20 cm, as they moult underground

Humidity should be 75–85%. The substrate should feel damp throughout, like a wrung-out sponge. Mist the sides and surface as needed to maintain this. Never allow the substrate to dry out; dehydration is the most common cause of death in captive giant millipedes.

Feeding

Adults graze constantly and need a steady supply of food available at all times. They eat primarily:

• Well-rotted wood and bark (the staple, replenish the substrate regularly)
• Dried oak and beech leaves (leave a thick layer on the surface)
• Vegetables: cucumber, courgette, sweet potato, butternut squash
• Fruits: banana, apple (sparingly, can attract mites)
• Cuttlefish bone, leave permanently in the enclosure

Calcium is especially important for A. gigas as they use it to form new body segments and harden their exoskeleton after moulting. Supplement with cuttlefish bone, eggshell powder, or calcium powder dusted over food.

Handling

Once settled, they will walk calmly across your hands. Support the full length of their body and never let the front end dangle unsupported. Let them walk between hands rather than gripping them.

If they curl into a ball, put them down and let them uncurl at their own pace. The secretion they release when stressed has a slightly oily, almond-like smell and can mildly irritate sensitive skin, so wash your hands after handling. Never handle during moulting or for at least two weeks after. Their new exoskeleton needs time to fully harden.

Mite management

Small white mites are very common in A. gigas enclosures. In most cases these are harmless grain mites that thrive in the same warm, humid conditions your millipede needs. To keep numbers under control, maintain good substrate hygiene and remove uneaten fresh food after 2–3 days. If mite numbers spike, reduce the amount of fresh fruit and veg temporarily and spot-clean the surface.

Substrate safety

Never use cedar or pine substrates (shavings, chips, or bark) in an A. gigas enclosure. The aromatic oils found in softwoods are toxic to millipedes and can be fatal. Always use deciduous hardwood, coco coir, and organic topsoil as described above.

Breeding

Breeding is very slow in captivity compared to smaller millipede species. Females lay eggs in the substrate, which can take several months to hatch. The young (pedelings) are tiny and grow extremely slowly. It may take 3–5 years for offspring to reach adult size, so be prepared to wait.