Tuesday, May 10, 2011


Today was such a beautiful spring day, the family and I went for a bit of a hike on the Shawangunk Ridge - if you know the area, we did the Overcliff/Undercliff Road loop from the Trapps parking area in the Mohonk Preserve.

One of the usual sights in spring along Undercliff Road, besides the abundant rock climbers and boulderers, are millipedes crossing the carriage road.  There were literally thousands (alive and squished).  Here are a couple of pictures (click to enlarge):

I believe they're Narceus annularis - one of the largest North American millipede species and I'm guessing they're out and about this fine spring day because they're looking for love.  Despite their intimidating appearance for those who dislike creepy-crawly things, they're mostly harmless although they can secrete a mildly irritating chemical when handled (it protects them from being eaten by predators like birds).

Despite their name, millipedes only have between 60 and 400 legs (depending on the species).  Two pairs of legs exist on each body segment (leading to their taxonomic classification into Class Diploda) except for the 1st and 4th segments, which have no legs, and the 2nd and 3rd, which only have one pair each.

The number of legs on the millipede is therefore 4 times the number of body segments minus 10.  I counted 57 segments (hard to do!) on the millipede pictured at right above which would work out to 218 legs which seems reasonable.  It's neat to watch them walk as their legs seem to ripple as they move.

Millipedes are detritivores eating leaf litter and other decaying vegetation.  They're relatively slow moving and can be distinguished from centipedes which have one pair of legs on each body segment.  Centipedes are faster moving and many can deliver a painful bite.

Millipedes have evolved very little since they first appeared about 428 million years ago in the Middle Silurian Period.  They were among the first arthropods to colonize the land following the appearance of early land plants like mosses.  Paleontologists have even identified a number of millipede trackways in some ancient rocks.

The nightmarish Arthropleura, a relative of centipedes and millipedes shown reconstructed at left, crawled through the primeval forests of the Carboniferous Period and grew to a length of 2.6 m (8.5 ft).

Sweet dreams!


  1. woah... can u give me info about centipedes?

  2. Hey, I loved your formula on calculating the number of legs on a millipede. No doubt your article is a good source of information on this species including that freaking restructured picture of Arthropleura.

  3. Wow, that's a big millipede! Is that real? Im afraid of bugs and anything that crawl..