Range: Australia, Africa, South America, Central America and Caribbean islands Habitat: Caves, forest floors, and other moist environments Size: 0.5-6 inches (12.7-150mm) long Diet: Termites, snails, worms, and more Threats: Birds, spiders, and snakes Life span: Five years or more

Transcript:

Today on Animal Fact Files we’re talking about velvet worms. When they were first discovered, velvet worms were originally thought to be slugs. Today they’re known as “worms” though they aren’t really worms, they’re not really arthropods either; but they have features of both and are often discussed as something in between worms and arthropods. The most recent research seems to indicate they’re more closely related to arthropods than annelids, but because they aren’t technically classified as arthropods as of this recording, and because they lack the segmented limbs found in true arthropods, we’re putting them in the “other inverts” playlist here on the channel - just know this could change with new information!

Like arthropods, velvet worms have different ways of reproducing. Most species are sexual reproducers meaning the males and females are separate and they reproduce with fertilization of a female’s egg by the male’s sperm; of course, every family, or in this case phylum, has its outlier, and with velvet worms it’s the species that reproduces via parthenogenesis. Scientists haven’t even found a male of this species! All the other species, however - of which there are more than 100 described - may produce eggs, which is less common; give birth to live young that hatch from eggs inside the mother, which is more common; or give birth to live young, which is the velvet worm’s most common method of reproduction!

Male velvet worms make packets of sperm, called spermatorpores, maybe dance them around on their heads - for… obvious… reasons - and then place them in a female’s genital opening or even just somewhere on her body. Velvet worms do this weird thing where their body just kind of absorbs the spermatophore and the sperm eventually make their way to where they need to be. Female velvet worms can retain sperm, so they’re still able to produce babies even if they can’t find a mate for long periods of time.

Depending on how they give birth it may be anywhere from six months to almost a year and a half for their babies to develop. In general, in the species that lay eggs, the development takes longer. The babies are born looking like miniature adults, and they can live more than five years growing to sizes anywhere from half and inch (12.7 millimeters) to half a foot (150 millimeters)! And they don’t even start breeding until well into their first year of life!

Like the tardigrades we’ve talked about previously, velvet worms have clawed feet; their scientific name actually represents this, but they don’t use the claws to hunt - for that, they use slime. Velvet worms shoot slime from modified feet on their heads to catch their prey. The slime gets super sticky when it’s exposed to air. Basically it’s like real life string shot.

Once captured, the velvet worms will bite through their prey using their “claw jaw” mouths and drip digestive salvia all over. Prey to velvet worms can include termites, snails, and… worms. Once liquidy, the velvet worm will slurp up the juices. Velvet worms may also use their slime to help protect them from predators such as birds, spiders, and snakes.

Generally, these animals are most active at night because they actively avoid light. They may also come out during the rain because they are pretty dependent on water. Velvet worms live in moist places such as caves, the undersides of logs, and the damp forest floor. They have to stay wet or else they’ll dry out.

Like millipedes they have holes over their bodies for breathing, but unlike millipedes they can’t close them, so they can easily dry out. Of course, they also don’t want to get too wet either, so their velvety looking bodies are designed to help repel unnecessary amounts of water.

Velvet worms are mostly found in the southern hemisphere. They take up residence in Australia, Africa, and South America. There are, however, some species found in tropical areas of Central America and Caribbean islands, as well.

For more facts on velvet worms, check out the links in the description. Thank you to Blank and SBs Animals for today’s request. Give a thumbs up if you learned something new today, and thank you for watching Animal Fact Files!