Overview
Acacio’s Velvet Worm (Peripatus acacioi) is an astonishing terrestrial invertebrate belonging to the phylum Onychophora, an ancient lineage of ‘velvet worms’ that has endured virtually unchanged for over 500 million years since the Cambrian period. Endemic strictly to tiny, fragmented pockets of the Atlantic Forest in Minas Gerais, Brazil, this enigmatic creature resembles a cross between an earthworm and a caterpillar. Clothed in a velvety, water-repellent pelt of microscopic papillae, it wields one of the most remarkable predatory mechanisms on Earth: twin slime-projecting cannons capable of immobilizing quarry from afar.
Biology and Physical Characteristics
Peripatus acacioi possesses a soft, hydrostatically supported cylindrical body supported by 28 to 32 pairs of unjointed, conical stub feet (lobopods) that terminate in tiny dual claws. Its skin is not a hard chitinous shell, but rather a velvety, hydrophobic cuticle covered in thousands of microscopic sensory scales that detect airborne vibrations and humidity gradients. On either side of its head sit oral slime papillae connected to massive reservoirs of proteinaceous glue; when hunting, it ejects twin oscillating jets of adhesive slime that cross mid-air, entangling struggling insects in a sticky, fast-hardening net within milliseconds.
Behavior and Ecology
Because their simple tracheal breathing pores cannot close, velvet worms are exceptionally vulnerable to desiccation and must live in microhabitats with near-100 percent relative humidity. Peripatus acacioi is nocturnal and cryptic, sheltering inside rotting hardwood logs or deep soil fissures by day and emerging at night to stalk the forest floor. Once prey is trapped in its hardened slime matrix, the velvet worm injects digestive saliva into the insect’s body, liquefying its internal organs before sucking up the nutrient broth. Reproduction is viviparous, with females gestating embryos internally for nearly a year and giving birth to fully formed miniature young.
Conservation and Human Impact
Classified as Endangered by Brazilian conservation authorities and the IUCN, Peripatus acacioi faces severe risks due to the catastrophic fragmentation of the Brazilian Atlantic Forest (Mata Atlântica). Extensive iron-ore strip mining around the Quadrilátero Ferrífero, urban sprawl around historic mining towns, and illegal wild collection have fractured its already tiny distribution. The Tripuí Ecological Station and local municipal reserves were created specifically to protect critical microhabitats for this priceless evolutionary relict.
Interesting Factoid
Acacio’s velvet worm hunts by shooting two rapid streams of sticky slime from cannons beside its mouth; the slime hardens into glassy threads within seconds, gluing fast-moving crickets to the ground before they can escape.
Last updated: October 2026