Hadrurus care thoughts

[MorbidArachnid]

I found this article that actually measures the conditions inside the burrow of Hadrurus arizonensis in the wild.

https://esajournals.onlinelibrary.wiley.com/doi/10.2307/1935378



This graph shows the temperatures of three scorpions in their burrow, compared to air and soil temp 20cm into the substrate. These measurements were taken in June in Arizona. The first surprising thing is that while the temperature in the burrows stayed more mild than the outside air, it still averaged around 35C. Scorpion "A" was noted to not have dug a deep enough burrow and died during this temperature transient though.


This graph shows scorpion "B" leaving the burrow at about 2am, being exposed to the much cooler temperatures on the surface, then returning to the burrow around 4am and warming up. The authors noted that the peak temperature at 20cm was actually occurring just after the peak surface temperature outside, and existed slightly under the surface of the soil. This is because the sun was heating up the soil throughout the day, and that heat was gradually transferring deeper and deeper into the soil. At night, however, the surface would rapidly cool off, and so the entrance of the burrow quickly cooled, while the heat that had been transferred deep into the soil would then have to transfer back up to the surface or deeper into the earth. Combined, this means deep in the substrate stayed at a very constant warm temperature. I also want to note that these measurements were only done for 3 days in June, I would like to see the temperatures over a longer period of time and in the winter also.

The other important thing to note is the humidity.


This paper was measuring 55-70% humidity in the burrow, even though the surface humidity was occasionally less than 5%.

I've been deep diving on Arachnoboards as well and collecting all confirmed instances of Hadrurus successful molts.

https://arachnoboards.com/threads/hadrurus-arizonensis-molt.368555/
This thread was the most recent, care was on sand/soil mix, kept dry, no opportunity to burrow, with a constant water dish.
https://arachnoboards.com/threads/another-hadrurus-molt-experimental-substrate.125124/
OP had two hadrurus molt, one on sand, one on "moon sand", doesn't give much info about water but does say keeps them at 86F. The scorpion on sand did not burrow, the one on moon sand did. Another user said theirs molted when offered water in some way and they spray theirs.
https://arachnoboards.com/threads/hadrurus-arizonensis-molt.190082/
Two molts, 2/3 clay 1/3 sand, allowed to burrow, kept "hot and relatively humid" with a false bottom set up, water was "down one side every now and then to keep the humidity higher near the bottom"
https://arachnoboards.com/threads/h-arizonensis-successful-molt.354300/
Clay/sand mixture, allowed to burrow. Owner "When spring came around, every 2 weeks or so I would "make it rain" to mimic monsoons. I would also overflow the water dish a bit. I also used a long set of metal tongs to create a vertical channel in the substrate, which I poured some water down and allowed it to trickle down into the bottom layers. I would let it almost completely dry out, then repeat the process again."
https://arachnoboards.com/threads/h...a-desert-hairy-scorpion-dying-of-molt.298491/
Kept on a mixture of substrate, not allowed to burrow, had half solo cup "humidity hides", "I added about a 1/2 cup of water once a week to each cup on top straight through the substrate and misted over top seashells and other rocks to create tiny pools of water for them to drink if they were out and about." Does note their friend kept them similarly without success.
https://arachnoboards.com/threads/hadrurus-arizonensis-finally-molted.321283/
"Temperature approximately 82F at its burrow location during the day, with the rest of its cage being slightly cooler 76F nighttime for the entire cage. Air humidity bounces around between 20%-40%. It always has a full water dish and uses it fairly regularly (every 2 weeks or so from what I have seen, probably slightly less than that though). I would occasionally very lightly mist one part of the cage just to add a small amount of humidity but in reality that probably didn't do too much." Scorpion appears to have been kept on clay, but did not make it's own burrow. Molted in half a cup "humidity hide" similar to previous post.

That's all I could find. I also talked to someone on discord who said they got their Hadrurus arizonensis to molt to adulthood by having a constant water dish and regular spraying with a sand/soil mixture for substrate, but I obviously don't have a link for this. It seems the main constant was having water available and be provided. Only about half of them allowed their scorpions to make a burrow, the other half used some sort of hide. These scorpions were at various sizes and instars. More information or data would be appreciated.

 

[darkness975]

For what it's worth my H. arizonensis all have a water dish. I have caught them drinking from it at various times over the years.

There are some who have sworn not to use a dish with them but I have always begged to differ.

 

[MorbidArachnid]

Another interesting thing I found today, a site where you can look up soil composition.


Compared with range of A. arizonensis

Doesn't seem like they live on clay soil at all, selected the 25-50cm depth option to account for some burrowing, but they still seem to primarily live on loamy sand.

https://casoilresource.lawr.ucdavis.edu/soil-properties/

Here's the site if you want to look at different stuff yourself, clay is primarily used to maintain a burrow and I suspect in the wild the sand is hard packed enough and there's enough stuff like roots to maintain a burrow even in dry sand.

 

[CRX]

Another interesting thing I found today, a site where you can look up soil composition.

View attachment 481415 View attachment 481416
Compared with range of A. arizonensis
View attachment 481417
Doesn't seem like they live on clay soil at all, selected the 25-50cm depth option to account for some burrowing, but they still seem to primarily live on loamy sand.

https://casoilresource.lawr.ucdavis.edu/soil-properties/

Here's the site if you want to look at different stuff yourself, clay is primarily used to maintain a burrow and I suspect in the wild the sand is hard packed enough and there's enough stuff like roots to maintain a burrow even in dry sand.

Roots seem to be pretty integral to them in the wild

 

[MorbidArachnid]

Not going to post the full article here for copyright considerations, but in Invertabrate Magazine 2014 Vol 13 Issue 3 there is an article about molting in Hadrurus arizonensis.

CAPTIVE ECDYSIS OF THE GIANT DESERT HAIRY SCORPION

Text and photos by Trevor Mann

"I kept them apart for the first month or so until I got things together and made a mix of play-sand from the hardware store and Excavator Clay from ZooMed. The mixture was two parts Excavator Clay per five parts of play-sand. I mixed them together while they were dry and then mixed them once more while misting with a spray bottle. This allowed me to make sure the mix was well-blended and packed down as I went along.

The clay mixture went on top of about two inches of pebbles (each around the size of a quarter) I had bought from the pet store less than five miles away from my home. As I added it, I held a PVC pipe in place so I would be able to pour water to the bottom, directly into the pebbles. After the fact, I measured the level of the clay-sand mix inside the 29-gallon aquarium. My goal was to hit eight inches, though it was a hair over that."

"The female scorpion was introduced to the enclosure first while the substrate was still drying via a red 75-watt directional bulb. The bulb might have been five inches above the surface of the sand, though I cannot remember what the levels were (it had to be at least 85 Fahrenheit because the substrate below the bulb was quite warm to the touch) for heat."

"It is also worth noting that the heat lamp was focused over one side of the enclosure, and that no water was giving to the scorpions in the form of a dish."

"I later excavated a small hole against the glass in which I inserted a humidity gauge on the cool side of the enclosure before burying it again with moistened substrate. Even weeks afterward, it would read around 70% where it was deposited three inches or so below the substrate."

No provided water, but they were set up in a false bottom set up with water poured into the lower layers. This report is interesting because the author actually measured the humidity of the substrate, which was reading at 70%. Author does not indicated how often water was added to the bottom nor if the humidity gauge was in the actual burrow, or just in the substrate near it. The subadult female was dug up 6 months later where the author found it had molted into adulthood.