Journal archives for August 2016

August 21, 2016

RARE Arizona Bark Scorpion with TWO Metasomas (Tails) and Stingers!

On Sunday evening, August 14, 2016, BJ Stacey (@finatic) and I were black lighting for insects in Madera Canyon, Santa Cruz County, Arizona, at the Carrie Nation Trailhead, when I decided to do a scorpion check with my handheld black light. I made a short walk along the edge of the parking lot - something I have done there countless times before - and stumbled across an expected species for the area known as the Arizona Bark Scorpion (Centruroides sculpturatus). This species is easily recognized by its frequently reddish coloration and contrasting dark back with a line of pale spots running its length.

I observed it for a minute before I realized that something was "off". By now BJ had arrived to photo it and it was at this moment that I noticed that it must be two individuals mating, which didn't sit very well with me because I hadn't ever seen mating scorpions riding each others' backs. When I quickly realized that there was only one set of legs and chelae, it suddenly dawned on me that I was looking at a single Bark Scorpion with two metasomas and two stingers! (View photos of this individual here: After exclaiming that I had a two-tailed scorpion I quickly pulled a vial out of my pocket and VERY CAREFULLY collected it. Arizona Bark Scorpion is by far the most venomous scorpion north of Mexico and is well known in its range as causing severe pain following a sting, and can even lead to death in the very young or very old. In Arizona, it is frequently found in peoples' homes where of course most often they are promptly dispatched. In the case of this juvenile individual, it is quite small, so it would likely have some trouble breaking human skin without a very precise and direct contact, if it can at all.

After bringing it home alive and well, and after gaining permission from my wife to maintain such a creature at least for a period of time (!!), I released it into a terrarium I have ready to accept a scorpion for observation. Her thought was the same as mine that something so rare should be observed to document its behavior. We are experienced with scorpions in captivity, having kept multiple scorpions for this purpose in the past, typically releasing them back where they were found at some point. This specimen will likely never be released, largely in part to the fact that typically these don't survive very long in the wild (or in captivity, for that matter) due to molting issues. That said, there are very few examples.

Scorpions with two tails are extremely rarely observed, and one estimate I found online said that it occurs in only one of every 5,000 individuals. It is my first. Others who are far more experienced with scorpions than I, and who have themselves observed many thousands of individuals have told me they have not yet found one.

I have not been able to fully examine this specimen as yet to determine the exact structural characteristics of the double metasoma, but one other feature worth mentioning is that its right lower chelal claw is significantly stunted, rendering that claw unusable for grasping. See below for additional behavioral information pertaining to its chelal use.

I will use this journal entry as an ongoing record of my observations of this individual, so please check back over time for updates. I look forward to your thoughts and comments, and I'll say it now to get it out of the way - It is not for sale or trade (and I have already turned down offers).

FYI @miketroll @sidesplotch @jmaughn @dominic @rjadams55


8/15/16 - Placed in its terrarium of sandy substrate and a hiding place. Walking around acquainting itself with its new home.

8/16/16 - Small insects including a winged termite and beetles placed in its enclosure, but it is not interested. Getting worried that it may not eat. Placed water droplets in the sand, and it quickly went over to it and very obviously laid down in it. Do they absorb water through their bodies? Added a shallow water dish.

8/17/16 - Caught a small moth at my light and dropped it in.

8/18/16 - In the morning I found four moth wings (phew!) and a still-alive termite (now wingless). Removed the termite. Does not like termites, check! (NOTE: All scorpions seem to be somewhat finicky eaters, so trial-and-error is important. No scorpion that I have kept has ever turned down a moth though).

8/20/16 - Caught a greenbottle fly and removed a wing before dropping it in the enclosure. Now well-hydrated and having eaten a couple of days prior, it aggressively ran toward the fly, grabbed it with its one good chela (the other also being used as a prod) and incredibly stung it accurately with BOTH stingers almost simultaneously! It is quite interesting that it would be able to accomplish this considering scorpions have evolved over millions of years to hunt with a single stinger. I will seek to photo/video document this in the near future.

8/20/16 - Metasoma function: I have been observing the individual's use of its metasomas since capture, and can state that they are each fully and seemingly equally functional in every manner. They are sometimes held over the body, sometimes both off to the side, and sometimes one up with the other down. While eating the fly, it crossed them (I will resist the temptation to anthropomorphize!)

8/22/16 - Ate two small moths, but I was not able to witness the kills.

8/23/16 - Consumed an Alfalfa Looper moth that was bulkier than itself (with one forewing removed). This individual has zero issues with kills, despite its one stunted chela.

8/26/16 - Some type of buildup collected in one of its metasomas, so I removed the buildup with forceps and moved the scorpion to a dry habitat in case it is a cause of the buildup.

8/30/16 - Tail buildup has not returned, so hopefully was a one-time event. It is eating voraciously almost daily, including a termite (so scratch the earlier reference to not liking termites).

9/17/16 - I re-configured its enclosure using pulverized coconut husk as the substrate, which it much prefers vs. sand and is more like its normal habitat. I will mist the aquarium glass periodically to maintain appropriate moisture levels.

10/14/16 - I captured a brief video of the scorpion attempting to kill a cricket, though the cricket proved a bit too fast (video link posted just below). I feel this was a half-hearted attempt, as it did not make subsequent attempts on it. This gives a good solid impression of this scorpion's routine of stinging prey with both stingers simultaneously. I'll try again with this same cricket soon, and hopefully capture an actual kill.

10/26/16 - After 83 days in captivity, it has finally molted (ecdysis)! This photograph was taken approximately two hours after it completed the task, apparently with perfect success. Interestingly, the right lower claw (visible in this photo) which was already malformed at the time of discovery, has lengthened relative to the upper claw. I suspected that it would soon be shedding its exoskeleton after it began to shun any prey twelve days prior.

10/31/16 - Took a cricket for the first time since its pre-molt fast began on October 14. It is still a tiny bit soft, so I monitored it carefully after introducing the cricket to make sure no damage was done. It wasn't particularly proficient with its stingers yet, and it didn't sting it before simply starting to eat its head. It still cannot grasp with its right claw, despite the slight relative lengthening following the ecdyisis, but used it as a prod as it had prior.

4/4/18 - Minor update that this individual is still doing well in captivity. It has not molted since 10/26/16.

Posted on August 21, 2016 01:54 AM by jaykeller jaykeller | 1 observation | 41 comments | Leave a comment


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