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by John M. Regan

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CENTIPEDES 101

John M. Regan

Centipede

            Centipedes are a fascinating branch of the arthropod order of animals grouped under the Class Chilipoda – many footed - an apt description of this resident of the unseen world beneath our feet.  The term Centipede, “100 feet,” is not, however, totally or accurately descriptive.  Centipedes may have anywhere from ten to over a hundred “feet.”

            But while the centipede’s name reflects its most immediately visible characteristic there is a lot more to this creature.   “Centipredator” might have been a better name, because they most certainly are predators, and masters at the game.  All those legs propel this invertebrate with great speed and under the head is the business end of the animal, a pair of powerful fangs called forcipules.  Forcipules differ from all other types of fangs in the reptile and arthropod world; they not true mouthparts, they are modified legs, but so completely adapted to their purpose that they even have venom glands running to the tips. 

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             Although centipedes are poisonous (otherwise why have venom glands, right?), most are not excessively dangerous to humans.  I have italicized the word excessively here because I believe this depends more on the individual reaction than the actual toxicity of the poison.  Despite numerous sources that state that centipede bites are not particularly harmful, I know a fellow soldier who was bitten in Hawaii and had a really rough time.     

 Centipede Centipede Centipede

Varying lengths.  The little fellow on the left barely measured a half an inch while the big guy in the middle went half a foot.  The one on the right was somewhere in the middle range.

            Just about everyone has seen a centipede or a millipede, recognized the similarity, but correctly observed that the two animals were just not the same.  It is relatively easy to determine the difference: pick up a centipede and it will probably bite you; millipedes won’t.  What’s that?  You say you’d rather not try that kind of a species test?  Well, okay, here’s another way to tell.  In general centipedes have one leg per body segment; millipedes have two legs per body segment.  Millipedes, despite having twice as many legs, move a lot slower and are not as moisture dependent as their lesser legged cousins.  Millipedes are often seen strolling slowly about in the middle of the day while centipedes remain hunkered down under rocks and logs.

            An interesting fact about centipede legs is their relative length.  Apparently someone actually has measured them and found that the foremost leg is slightly longer than the leg behind it, thus aiding coordination of all those appendages.

            Of course, I highly discourage picking up a centipede.  Those forcipules, in addition to being poisonous, are powerful.  A large centipede can deliver a painful puncture with or without venom.  There are, however, safe methods to pick one up.  A pair of medical forceps, for example, works extremely well.  But in case you are not a doctor or related to one there are alternatives.  Needle nosed pliers do the job.  For the nimble of finger, even a pair of chop sticks will suffice.  (I have actually done this and it works.)  For the photos below, however, I used the pliers function on my Gerber knife.  Whatever you decide to use, please be careful for yourself and the animal.  Centipedes are tough, but you can easily hurt them and I hate to see any of my little friends suffer.  The animal I captured for the photos below was released unharmed.

Centipedeheld with pliers  Centipede held with pliers  Centipede by John M. Regan

Hold 'em, but don't hurt 'em.  And that goes for you, too.  Those forcipules (fangs) can inflict some damage.

            Why would you want to pick up centipede anyway?  Observation, of course.  The buggers are fast and trying to observe one is pretty difficult when all those legs kick in to high gear.  Centipedes shun the limelight and the sunlight.  The first thing one will do when you find it under a log or rock is scramble to safety.  Safety to a centipede is anything in can crawl into or under; either way it makes close observation very difficult and you really can’t appreciate the anatomy of these fascinating animals until you slow it down somehow. 

            Something you notice right away in examining your Chilipoda specimen are the segmented body parts.  These segments grow at different rates throughout the creature’s life; the rate of growth depends on the species.  Attached to each segment is a single pair of legs, one leg on each side as opposed to millipedes which have two.  Each leg ends in a tiny claw.  The head is fairly flat and a pair of long, distinctly segmented antenna protrudes from it.  At the base of the antenna you’ll notice a pair of small dark spots.  These are compound eyes, although most research indicates that centipedes are only capable of sensing light from dark.   Detection of prey is done using the antenna, and I suspect smell and detection of minute vibrations of potential prey.

Centipede leg  Clown Mlilipede  Red Millipede

Centipede versus millipede.  The close up picture on the left clearly shows the single leg pair sprouting from each segment of the centipede's body.  Note the tiny claws at the end of each leg.  The other photos display the double leg pair per body segment of a millipede.

            Directly under the centipede’s head are the powerful, fanged mandibles called forcipules discussed previously.  Note the centipede’s tail.  A pair of bristled appendages juts out from the back end.  These appendages act as a kind of “rear view window” antenna. I’ve seen these appendages wriggle in an odd twitching motion while the rest of the animals had buried itself in the ground, almost as if they were radar searching for a signal.   This might also serve as a defense mechanism designed to fool predators as to which end is which.

Centipedehead shot  Centipede head on  Centipede forcipules Centipede Tail

From left to right:  The centipede head showing the small compound eyes and segmented antenna.  Mouthparts include the mandibles and above them the maxillae.  The next photo gives a clear shot of the powerful, venom injecting forcipules.  At the far right are the sensitive pair of appendages at the rear of the centipede.

            Although they have not achieved the notoriety of scorpions and camel spiders, centipedes have inspired some fairly wild tales.  As previously discussed they are not deadly poisonous and they are not out to hunt unsuspecting humans.  Although they do reach respectable lengths of up to twelve inches, that is about the maximum.  The largest is said to be the Amazonian Giant Centipede, but the Texas Giant Centipede is claimed to reach lengths in excess of one foot as well.  (But what else can you expect of a Texan centipede?)  I’ve also read claims of the Giant Peruvian Centipede reaching lengths over twelve inches.  There are even one or two You Tube videos featuring a centipede attacking and eating a mouse. 

As usual in these cases overactive imaginations and storytelling prowess often prevails over reality so beware of outrageous claims; it appears that one foot is about maximum, but hey, that’s a big chilipoda!  They largest member of the class I have seen measured just about six inches long.  But even that is a big centipede and is a bit startling when it appears unexpectedly. 

            What about the smallest?  A recent story in the New York Times (in the opinion column of all places) claims the discovery of a 0.4 inch “Central Park Centipede” Nannarrup hoffmani, more properly called Hoffman’s Dwarf Centipede, is the smallest in the world.  Certainly a little guy, but is it the smallest? I don’t know, there are a lot of centipedes in the world and they aren’t all easy to find, but the Guinness Book of World Records does indeed list this little centipede as the smallest.  In a relatively small patch of ground during my own observations I’ve seen these guys range in size from that mentioned above (and maybe smaller) inch to in excess of six inches.  I have seen five or six different species in an area no bigger than child’s swimming pool.  Gives you an idea of how many there must be worldwide.  The number of centipedes worldwide must be staggering, but that’s to be expected in a lot of invertebrates so I am always suspicious about definitive claims with these guys in regard to numbers and size.  For now, however, let’s take the good Guinness people at their word.

     House Centipede  House Centipede  House Centipede

The odd little House Centipede.  About one half of an inch long these guys are very fast and difficult to photograph in their natural habitat.  Sometimes you get lucky when the little fellows are occasionally "sun stunned" for a moment or two. 

 Most centipedes sport that long, lean, dangerous look, but there is an exception to the rule.  The House Centipede, of which there are several species, has taken a new tact with a much shorter body and much longer legs.  Apparently the common name comes from their fondness for human habitations, I’ve always thought the name Hairy Centipede to be more descriptive of these mop like centipedes.  Although I cannot claim to have ever seen one in my home, they must be a common nuisance judging from the number of products and companies that claim methods to get rid of them. 

So there you have it – your non credit Centipede 101 course.  But if you interested in furthering your chilipodian education I recommend the following sources:

Oklahoma State University:

http://pods.dasnr.okstate.edu/docushare/dsweb/Get/Document-2295/EPP-7316web.pdf

Iowa State University:

http://www.ipm.iastate.edu/ipm/iiin/housece.html Iowa State

The Pied Piper:

http://www.the-piedpiper.co.uk/th11d.htm 

HOOAH

Jack

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