Velvet worms (also named Onychophora) have been in global existence for an estimated 500 million years. Currently, there are 2 main families containing well over 100 species, with a global distribution across the Southern Hemisphere.
The family named 'Peripatidae' has fewer species and is found in the tropical region of the Caribbean, Mexico, North, South and Central America, equatorial West Africa, and South East Asia (India, Thailand and Indonesia and parts of Malaysia).
The family named 'Peripatopsidae' is found in South Africa, where 9 species have been studied. They're also in Chile, New Guinea, New Zealand and Australia, which has the greatest diversity and abundance, with 74 species, mostly found in Tasmania.
The global regions of the velvet worm are currently restricted to the Southern Hemisphere, although fossils have been found in the fossil resin Baltic Amber, indicating that they were once to be found in the Northern Hemisphere, when conditions used to be more suitable.
Tasmania is their main home and in this region they're found in the wet Eucalypt woodlands and forests to the South and the East of the Tasmanian Central Plateau. It's interesting to note that 3 species living here are protected by the Tasmanian Threatened Species Protection Act 1995.
Velvet worms are land-based creatures with the majority of species living in relatively moist coastal areas and tropical/temperate rainforests. They prefer damp, dark habitats with high humidity because they breathe through little holes distributed all over their bodies that are permanently open so, as easily as water can be absorbed, it can easily be lost. They are, therefore, very susceptible to dehydration.
Since they lack any kind of skeleton, they're able to crawl through very narrow passages and find places that are safe, dark and humid. Their ideal home is in places such as moss cushions, rotting logs, the underside of tree trunks, beneath stones, in termite tunnels and amongst leaf litter. They've also been found living in grasslands, but only if the soil has enough cracks into which they can crawl during the daytime.
Biologists have discovered 2 species living in underground caves, which provide an ideal habitat since they can squeeze themselves into tiny cracks in the rocks, where consistently dark, damp living conditions can be permanently maintained.
Farming and modern agricultural practices are thought to have created new habitats for the velvet worm where, for example, cocoa and banana plantations in South America and the Caribbean are home to some species, providing that they've not been killed off by pesticides.
Velvet worms are nocturnal carnivores. They avoid daylight and are normally well hidden away from view. Since dehydration is most likely during the day and in dry weather, they tend to come out mostly at night and during rainy or damp weather. If the weather turns cold or dry, they look for tiny cracks and crevices into which they can crawl and rest until conditions are more favourable.