Speaker 1: Welcome to brain Stuff production of iHeartRadio. Hey brain Stuff,
Speaker 1: Lauren bog obamb Here. Let's start with the basics. Millipedes
Speaker 1: are not worms, nor are they insects. Insects have six legs,
Speaker 1: and obviously millipedes have many more. But exactly how many
Speaker 1: more The answer may vary by the particular specimen in question,
Speaker 1: but it's never going to be nine ninety four. It
Speaker 1: turns out that no one chose their name millie meaning
Speaker 1: a thousand, and pedes referring to feat as a way
Speaker 1: to convey the precise number of legs. These organisms have
Speaker 1: their cousin, the centipede, with the prefix centi meaning a hundred,
Speaker 1: are similarly named by way of illustration, not precision. Millipedes
Speaker 1: fall within a subphylum of arthropods. All arthropods have in
Speaker 1: common a hard exoskeleton, segmented bodies, and jointed legs, like arachnids, insects,
Speaker 1: and crustaceans. What distinguishes millipedes is that they have many
Speaker 1: segments in their body, and for each segment, they have
Speaker 1: two pairs of legs instead of one pair, as you
Speaker 1: would see with say, centipedes having so many legs as
Speaker 1: part of what makes millipedes so adaptive. Fossil evidence suggests
Speaker 1: that millipedes were among the first ever terrestrial animals, which
Speaker 1: means they've been around for about four hundred million years.
Speaker 1: Back in the Coniferous Period, about three hundred million years ago,
Speaker 1: a millipede species known as arthur Plora grew to an
Speaker 1: enormous six and a half feet long and one and
Speaker 1: a half feet wide that's about two meters by a
Speaker 1: half a meter. Today, millipedes range in size, thank goodness,
Speaker 1: from just a tenth of an inch or three millimeters
Speaker 1: to about eleven inches or a third of a meter.
Speaker 1: So far, researchers have discovered about twelve thousand species on
Speaker 1: every continent except Antarctica, but estimate that there could be
Speaker 1: as many as eighty thousand species here in the United States,
Speaker 1: every state has some species of millipedes that are unique
Speaker 1: and can't be found anywhere else. Scientists have developed new
Speaker 1: imaging techniques that use u VY light to help them
Speaker 1: differentiate between millipede species. This approach works because millipede exoskeletons
Speaker 1: and reproductive organs glow under u VY light, as is
Speaker 1: the case with many other arthropods like scorpions. Some species
Speaker 1: of millipede in California, however, are bioluminescent, which means they
Speaker 1: glow in the dark. Millipedes feast on leaf litter that's
Speaker 1: plentiful around the world. This means millipedes spend most of
Speaker 1: their time in soil, under leaves and rocks. And what
Speaker 1: makes them so effective at getting around in this dense
Speaker 1: habitat is there many mighty legs. They use the first
Speaker 1: segment of their body like a bulldozer, and having so
Speaker 1: many legs means they have a lot of power with
Speaker 1: which to push burrowing through the dirt. When millipedes hatch,
Speaker 1: they have only a few pairs of legs. Then, just
Speaker 1: like many other arthropods like crabs and spiders, they grow
Speaker 1: through a process called molting. This process involves shedding their
Speaker 1: exoskeleton and growing a new one. Each time they do this,
Speaker 1: millipedes also grow a new segment and therefore two new
Speaker 1: pairs of legs. Some millipedes stop molting when they reach adulthood,
Speaker 1: and others molt their whole lives, which is on average
Speaker 1: about two years. So how many legs to millipedes have
Speaker 1: it depends on the group, but it ranges between twenty
Speaker 1: four and seven hundred and fifty at most, though that's uncommon.
Speaker 1: Most millipede species have under a hundred legs. Millipedes have
Speaker 1: some defense mechanisms, but they don't bite or sting. They
Speaker 1: have very poor eyesight. Some species have no eyes at
Speaker 1: all and mostly just use their antenna to find their way.
Speaker 1: A millipedes best move when it feels threatened is to
Speaker 1: curl up in a ball and secrete chemicals that ward
Speaker 1: off predators. The chemicals they secrete vary, but are released
Speaker 1: in such tiny quantities that they're generally not hazardous to humans.
Speaker 1: Some research describes how in certain tropical regions, monkeys actually
Speaker 1: seek out millipedes and use the chemicals they secrete as
Speaker 1: mosquito repellent. Centipedes, by contrast, can bite using small things
Speaker 1: that do secrete venom. Even then, while a centipede bite
Speaker 1: can be painful, it usually won't cause other harmful effects.
Speaker 1: If you're looking to tell the difference between a centipede
Speaker 1: and a millipede, legwise, centipedes legs tend to spread out
Speaker 1: to their sides, while millipedes legs point downward. Centipedes only
Speaker 1: have one pair of legs per segment, while millipedes have
Speaker 1: two pairs. If you're not keen on getting close enough
Speaker 1: to check, observe the creature's behavior. If it runs away quickly,
Speaker 1: it's likely a centipede. If it just curls up, it's
Speaker 1: probably a millipede. Today's episode was written by Danielle Duez
Speaker 1: and produced by Tyler Clang. Brain Stuff is a production
Speaker 1: of i Heeart Radio's How Stuff Works. For more on
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