FaunaHub

Velvet Worm (phylum Onychophora)

InvertebrateLiving fossilPredator

Velvet worm (Peripatus), a soft, caterpillar-like animal with stubby legs.

Velvet worm (Peripatus juanensis).

Image: Wes Gapp, CC BY 4.0, via Wikimedia Commons.

Overview

Velvet worms (phylum Onychophora) are soft-bodied, caterpillar-like land animals with rows of stubby, clawed legs and a velvety, often beautifully patterned skin. They are not true worms, nor insects — they belong to their own ancient phylum, closely related to the arthropods (insects, spiders, and crustaceans). Velvet worms are sometimes called “living fossils” because their body plan has changed remarkably little over an immense span of time, with relatives stretching back roughly half a billion years.

For such small, slow, gentle-looking creatures, they are formidable predators — thanks to an extraordinary weapon: they hunt by shooting jets of sticky slime to trap their prey.

Note: there are many velvet worm species; details here cover them broadly. Treat general statements as approximate and verify against authoritative sources.

Habitat & Range

Velvet worms live in moist habitats in tropical and temperate regions of the Southern Hemisphere and the tropics — in rainforests and damp forests, hidden in leaf litter, rotting logs, soil, and crevices. Because they lose water easily through their skin, they need humid, sheltered places and are mostly active at night or after rain.

Diet

Velvet worms are carnivores that hunt small invertebrates such as insects, spiders, woodlice, and worms. Their signature method is to squirt two jets of sticky slime from glands on either side of the head, entangling and immobilising the prey in a gluey net. The velvet worm then bites into the trapped victim, injects saliva to begin digestion, and feeds — even recycling some of its own slime by eating it.

Behavior

Velvet worms creep slowly on their soft, fluid-filled legs, feeling their way with a pair of antennae, and approach prey stealthily before unleashing their slime from close range. The slime is fired as fast-oscillating jets that can reach a small distance and quickly turn into a sticky tangle. Some velvet worms are surprisingly social, living in groups and even hunting cooperatively in a few species, with a dominance hierarchy. Many give birth to live young, and some nourish their developing offspring inside the body — advanced traits for such an ancient lineage.

Human Interaction & Conservation

Velvet worms are harmless to people and rarely seen because of their secretive, moisture-loving habits, but they are of great interest to scientists for what they reveal about the evolution of arthropods and early animal life, and for their remarkable slime. They depend on damp, undisturbed habitats, so forest loss and drying threaten some species. Consult authoritative sources for details.

More photos of the velvet worm

A velvet worm on the forest floor, showing its many stubby legs.

Velvet worm (phylum Onychophora).

Image: Wes Gapp, CC BY 4.0, via Wikimedia Commons.

Frequently Asked Questions — Velvet Worm

Is a velvet worm a worm or an insect?
Neither. Despite the name and worm-like look, velvet worms belong to their own ancient phylum, Onychophora, which is closely related to the arthropods (insects, spiders, crustaceans). They sit near the base of that broad group and have kept a very old body plan, which is why they're called 'living fossils.'
How do velvet worms catch prey?
By shooting slime. A velvet worm fires two jets of sticky fluid from glands beside its head, oscillating them rapidly to spray a gluey net over small prey like insects and spiders. Once the victim is entangled and stuck, the velvet worm bites in, injects digestive saliva, and feeds — and it often eats some of the spent slime to recoup the resources.
Why are velvet worms called 'living fossils'?
Because their body plan has changed so little over an enormous span of time. Velvet worms belong to an ancient lineage with relatives going back roughly half a billion years, and modern species still resemble those very old forms. Studying them helps scientists understand the early evolution of arthropods and related animals.
Are velvet worms dangerous to humans?
No — velvet worms are completely harmless to people. They are small, slow, secretive animals that prey only on tiny invertebrates using their slime. They have no interest in, or ability to harm, humans, and most people never encounter one because they hide in damp leaf litter and logs.

Sources and further reading

Authoritative wildlife references used for general educational context. Conservation status should always be verified against current IUCN Red List data. External links open in a new tab.