Velvet worms live in moist, dark microhabitats across the tropics and southern hemisphere, hiding inside rotting logs, leaf litter, soil, and occasionally caves. Around 200 species have been described, split into two families whose ranges trace back to the ancient supercontinent Gondwana. Their soft bodies and thin outer covering make them extremely vulnerable to drying out, which is why you’ll never find one in an open, dry environment.
Two Families, Two Halves of the World
The roughly 200 known velvet worm species belong to two families with strikingly different ranges. The first, Peripatidae, follows a belt around the tropics: Southeast Asia, West Africa, and Central and South America, with the vast majority of its 76 or so species concentrated in the Neotropics. The second, Peripatopsidae, is a southern-hemisphere group of about 111 species found in Chile, South Africa, Australia, and New Zealand.
This split isn’t random. It’s a direct imprint of continental drift. Peripatopsidae neatly divides into a western clade (South Africa and Chile) and an eastern clade (Australia and New Zealand), mirroring the breakup of the supercontinent Gondwana into western and eastern halves roughly 170 million years ago. The split between Chilean and South African species, estimated at around 154 million years ago, lines up with the opening of the South Atlantic Ocean. There is little evidence of velvet worms crossing oceans after their landmasses separated. They simply stayed put while the continents drifted apart.
Why They Need Constant Moisture
Velvet worms breathe through tiny pores in their skin that they cannot close. This means they lose water continuously, at rates measured around 57 milligrams per hour in lab conditions. About a third of that water loss comes directly from respiration. Without a waxy or hardened outer shell like insects have, they desiccate quickly in open air. This single constraint dictates almost everything about where velvet worms can survive.
The result is a life spent in perpetual dampness. Rotting logs are prime real estate: the interior stays humid, temperatures are stable, and prey is plentiful. Leaf litter on the forest floor, crevices in soil, and the underside of rocks also work, as long as moisture stays high. In New Zealand, researchers have found velvet worms active on the forest floor at night when conditions are cool and damp, roaming across rocks, trees, and among epiphytic plants and lichen. But when the air dries or the sun comes up, they retreat underground or into wood.
Life Inside Rotting Logs
In Australia, one well-studied species, Euperipatoides rowelli, is what ecologists call saproxylic: it lives in and depends on decaying wood. Individuals spend their lives inside rotting logs in montane forests, hunting small invertebrates in the largely dark interior. Dispersal between logs is risky because conditions outside are drier and more exposed. Even moving from one gully to the next can be a barrier, since the ridges between drainage areas tend to be cooler and drier, supporting fewer velvet worms.
This log-bound lifestyle has left a genetic signature. Populations in the Tallaganda region of southeastern Australia contain deeply divergent genetic lineages, suggesting that velvet worms persisted in sheltered gullies for extremely long periods, with little mixing between neighboring groups. For an animal that can barely survive a short trip across open ground, a ridge or a dry stretch of forest can be as effective a barrier as an ocean.
New Zealand’s Surprising Diversity
New Zealand hosts a remarkable number of velvet worm species for its size. The genus Peripatoides alone includes multiple species spread across both the North and South Islands, each with a relatively restricted range. Peripatoides novaezealandiae, for instance, is limited to the southern parts of the North Island around Wellington. Another species, Peripatoides indigo, is known only from the northwest corner of the South Island near the Wakamarama Range.
Other species fill in the map: Peripatoides sympatrica has a wide distribution across the North Island, while Peripatoides taitonga occupies Southland and southern Otago on the South Island, from the Catlins coast inland to the Blue Mountains. One recently described species, Peripatoides otepoti, ranges from southern Canterbury to Dunedin and has been found in native forest, scrub, pine plantations, swamp edges, and under rocks. The habitats are varied, but they share the same requirement: reliable moisture. Specimens are typically collected from decomposing logs, humus beneath native vegetation, under rocks during the day, and on cave walls and trees at night.
Cave Dwellers
A handful of velvet worm species have taken the preference for dark, humid places to its extreme by colonizing caves permanently. Only two true cave-adapted (troglobitic) species are known, one from each family. Speleoperipatus spelaeus was discovered in the 1970s in Pedro Great Cave in Jamaica’s Clarendon Parish and has since been spotted in only one other cave. It is one of the rarest velvet worms on record. The other, Peripatopsis alba, was first described from the Wynberg and Bat Cave systems on Table Mountain in South Africa and has been collected only a handful of times since 1931. Both species are red-listed by the IUCN.
Threats to Their Habitat
The IUCN classifies the entire velvet worm phylum as vulnerable, with habitat disturbance identified as the greatest threat. Because these animals cannot survive even brief exposure to dry conditions, any disruption to their forest microhabitat can be catastrophic. Deforestation, urbanization, and climate change all reduce the patches of moist habitat they depend on.
The consequences are already visible. In South Africa, the species Peripatopsis claveriga declined after road construction and development destroyed much of its range. Another South African species, Peripatopsis leonina, has not been seen since 1900, when its habitat was converted to housing. These losses highlight how little buffer velvet worms have. An animal that cannot cross a dry ridge to reach the next log stand has no way to recolonize once its patch of forest is gone.