When rolled-up, predators are unable to unravel giant pill millipedes since the margins of their second and last dorsal plates fit perfectly into one another, creating a sealed ball.

[4] In the position of the male telopods, the females instead have a sclerotized subanal plate, which in some species such as those belonging to the family Arthrosphaeridae, is enlarged and is used to produce vibrations (stridulation).

Sphaerotheriida somewhat resemble the North American and Eurasian pill millipedes of the order Glomerida, but are generally larger in size (20–80 millimetres or 0.8–3.1 inches body length).

[10] Also on Madagascar, some giant pill millipede species exhibit island gigantism, reaching more than 9.5 cm (3.7 in) in outstretched length and a size comparable to an orange when rolled up.

[4][16] The Zephroniidae (synonym Sphaeropoeidae) occurs in southeast Asia from the Himalayas and China south and east to Sulawesi and inhabits some Philippines islands.

[19] Little is known about the ecology, development and life history of Sphaerotheriida, but apparently all species are detritivores, feeding on dead organic matter such as leaves and wood on the forest floor.

Like earthworms, they play an important role in decomposition; by breaking down decaying organic matter they release locked up nutrients back into the soil.

It is possible that giant pill millipedes rely on special bacteria in their gut, much as termites do, to exploit the nutritional value of otherwise indigestible material such as lignin.

[26] Apart from the rolling-up behavior of giant pill millipedes, camouflage may be an important defense mechanism against predators that hunt by sight, such as birds.

[4][31][32] The first modern phylogenetic study of Sphaerotheriida (simplified below) was conducted by Wesener and VandenSpiegel in 2009, using morphological data from 36 species in 10 genera.