# Those weird white circles on the shell



## cdmay (May 19, 2011)

In what is a strange coincidence I have had a few worried people in the past several weeks contact me and ask about what they described as 'weird circles' or 'water marks' or even 'white squiggles' on the shells of their young tortoises. In one case I got photos showing these things pretty well.
Here are some examples...












They are most evident on the plastron but can ever appear on the larger legs scales...






But they come and go as the tortoise grows. In these next two photos taken a couple of weeks apart you can see that the rings have spread out and faded just in that short period of time. Eventually they fade away and blend into the shell...











So the question arises, what are they? Why do they appear? Here is my answer----I don't know. I would guess that it has something to do with layers of keratin (or other shell material) being laid down as the young tortoise is growing but that is just speculation on my part. 
But I do know that I have seen these things come and go in many species of turtle and tortoise that I have raised over the years. It seems to be a quite natural, and most importantly, harmless part of the growing process.


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## Yvonne G (May 19, 2011)

This question has come up a couple times before here on the forum, and even our MIA resident expert, Danny, doesn't know what or why. I was told many, many years ago that it was the calcium working its way through the keratin, but I don't really know for sure either.


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## bikerchicspain (May 19, 2011)

I had a tort with those same markings, but they disappeared as the tort grew, not a clue what they are.


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## cdmay (May 19, 2011)

Maybe they are tortoise crop circles like the ones made by aliens in fields during the night...


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## Fernando (May 19, 2011)

cdmay said:


> Maybe they are tortoise crop circles like the ones made by aliens in fields during the night...



Good point. Be Careful...


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## dmarcus (May 19, 2011)

My hatchling Sulcata has them on his shell, he didn't have them when I got him but the appeared a little bit after.


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## bikerchicspain (May 20, 2011)

cdmay said:


> Maybe they are tortoise crop circles like the ones made by aliens in fields during the night...


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## Tom (May 20, 2011)

Just an observation: I tend to see those squigglies more on my little ones after they've been outside in the dry air for an hour or two. Within an hour or so of soaking them and putting them back in their humid enclosures, the lines fade again.

I read the title of this thread and saw the author and I got all excited thinking we were going to get a definitive answer...

D'oh!!!


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## GeoTerraTestudo (May 20, 2011)

Tom said:


> Just an observation: I tend to see those squigglies more on my little ones after they've been outside in the dry air for an hour or two. Within an hour or so of soaking them and putting them back in their humid enclosures, the lines fade again.
> 
> I read the title of this thread and saw the author and I got all excited thinking we were going to get a definitive answer...
> 
> D'oh!!!



I had never seen nor heard of these circles/squiggles until I had read this thread. Very interesting. Perhaps it is significant that they appear on the plastron, and not the carapace. Perhaps it is a response to elevated moisture levels under the tortoise's belly, or maybe to a rapid change in moisture (being taken inside or outside, where the substrate is very different from one environment to the next).

Maybe it would be helpful if those who have observed these marks on their tortoises gave a brief synopsis of the type of tortoise they have and the conditions under which it is kept. So, to give a hypothetical example:

"Red-footed tortoise, female, age 4 months
Indoor tortoise in a 4' x 4' enclosure with coconut coir as substrate
Ambient temp 75 F; basking temp 95 F; nighttime temp 65 F
Relative humidity 50%; substrate moist
Diet is usually daily servings of endive, collard and/or mustard greens sprinkled with supplement
Observed marks on plastron after taking tortoise outside for 1 hour
Outdoor activity consisted of walking on grass and feeding on clover"

Something like that. Maybe that way, we could start to see a pattern emerging. Just a thought.


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## cdmay (May 20, 2011)

[_quote='GeoTerraTestudo' pid='253607' dateline='1305913287']
I had never seen nor heard of these circles/squiggles until I had read this thread. Very interesting. Perhaps it is significant that they appear on the plastron, and not the carapace. Perhaps it is a response to elevated moisture levels under the tortoise's belly, or maybe to a rapid change in moisture (being taken inside or outside, where the substrate is very different from one environment to the next).

Maybe it would be helpful if those who have observed these marks on their tortoises gave a brief synopsis of the type of tortoise they have and the conditions under which it is kept. So, to give a hypothetical example:

"Red-footed tortoise, female, age 4 months
Indoor tortoise in a 4' x 4' enclosure with coconut coir as substrate
Ambient temp 75 F; basking temp 95 F; nighttime temp 65 F
Relative humidity 50%; substrate moist
Diet is usually daily servings of lettuce, endive, and/or mustard greens sprinkled with supplement
Observed marks on plastron after taking tortoise outside for 1 hour
Outdoor activity consisted of walking on grass and feeding on clover"

Something like that. Maybe that way, we could start to see a pattern emerging. Just a thought.
[/quote]_

That is good reasoning but then these things commonly appear on fully aquatic turtles as well.


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## GeoTerraTestudo (May 20, 2011)

cdmay said:


> That is good reasoning but then these things commonly appear on fully aquatic turtles as well.



Interesting. I did not realize that. I wonder if it is a parasite burrowing under the scute? Or maybe it is a kind of "growing pain," where the bone underneath grows at a different rate than the keratinous scute overlaying it?


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## Tom (May 20, 2011)

Mine are usually on the carapace. We had a whole thread on this, but I can't find it now. It had pics and everything. All sorts of theoretical explanations were offered.


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## Fernando (May 20, 2011)

http://www.tortoiseforum.org/Thread-Strange-Circles#axzz1Mv0lC500

Is this it?


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## dmarcus (May 20, 2011)

My torts circles are on the carapace only..


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## Tom (May 20, 2011)

FernandoM said:


> http://www.tortoiseforum.org/Thread-Strange-Circles#axzz1Mv0lC500
> 
> Is this it?



That's not the one I had in mind, but its the same kinda thing.

Thanks Fernando.


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## zesty_17 (May 20, 2011)

my three toed box turtle has had them ever since i can remember, about 15 years at least, some of my cooters have them too, but i have no idea what they are. My turtles are otherwise healthy as can be.


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## Jacob (May 20, 2011)

dalano's baby Sulcata Hatchling had this also,


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## Terry Allan Hall (May 21, 2011)

cdmay said:


> Maybe they are tortoise crop circles like the ones made by aliens in fields during the night...



Yeah, that's probably it!... 

Alternately, I'm going with the calcium theory...


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