General Care Discussion :: Measuring Body Weights

[Insanity]

Thought I should begin monitoring my RES body weights, probably on a monthly basis or so.

A'Tuin weighed 943 grams and Morla weighed 814 grams. A'Tuin is larger by at least a half inch in my guesstimation.

So I am wondering what is the appropriate body weight for RES based on body length?
Neither one appears over weight or under weight, and can easily withdraw their legs and head.

A'Tuin by my guess is 6.75" to 7" while Morla is closer to 6.5".
Additionally, does anyone have a good method to measure body length? A'Tuin doesn't appreciate a ruler near her.
I've thought of getting perhaps a paper towel, laying them on it so the water on them leaves a body impression and measuring that, but the water would tend to spread out.

[steve]

There really isn't a baseline for weight when factors like water can affect the results. As for measuring length, maybe just have a place for them to walk around and when they stop, you can quickly go in for a measurement.

[Insanity]

I had the thought today of simply screwing two lengths of boards into an L-shape, mark off 0.25 inch increments and simply place them with the rear of the plastron against the vertical and then check against the marks on the horizontal.

I will do some searching and see if I can find some guidelines on body weights.

[Insanity]

I did find this from the Tortoise Library, written by Susan Donoghue, DVM. It is based on tortoises and box turtles, may not completely applicable for RES and other aquatic turtles, but i is a place to start.
https://sites.google.com/site/tortoisel ... t-and-size

The ideal body weight is determined with the formula:
tWt=SCL3x0.191

where;
tWt is the ideal target body weight in grams
SCL is the straight carapace length in centimeters

Using this, if my current guestimate for A'Tuin's length is 6.75 inches, which equals 17.15 centimeters, her ideal weight is 962 grams, she currently weighs 943 grams. She is a little underweight, but if she is closer to 6.5 inches in length, her ideal weight would be 859 grams, and she'd be a bit overweight.

Likewise for Morla, who I think is 6.5 inches, and the ideal weight is again 859 grams, and she currently weighs 814 grams, and as well would be a little underweight. If she is closer to 6.25 inches, her ideal weight would be 764 grams, and she'd be overweight.

This formula may not be the best for aquatic turtles like RES, but as it was derived from tortoises and box turtles, it should be good for them.
The site itself has other information that may be useful for tortoise and box turtle keepers.

[steve]

Very interesting page, I think it's good starting off point.

[Insanity]

I found some additional information, also for tortoises, though the poster is using it for the Giant Asian pond turtle.
http://www.heosemys.org/Jackson.php

The Jackson ratio formula is:

J=Wt/SCL3

where;
Wt is body weight in grams
SCL is straight carapace length
J is the Jackson ratio, which is unitless

Do some algebra and you get the same equation as above;

Wt=J x SCL3

The only difference is the Jackson ratio and the value of 0.191 in the above equation.

As it sounds like that board measured their turtles to get the equation, might this board be willing to do the same?
I'd be willing to do the math and graph plot.

[steve]

I made your topic a sticky. viewtopic.php?f=5&t=36180

[Insanity]

Thanks, I joined a couple of other sites too to ask there. Hopefully I get enough data, I've had a few responses already.