Jackson Ratio vs McIntyre Ratio.

[wemakegreatpets]

Which is best?

according to Jackson, my two old girls are between .19 and .20, which is perfectly healthy and desirable.

however my new boy (Got him a week ago) is over .25.., obese. He is 102.9 cm and 279 grams.

according to McIntyre he should be 306.5 grams at 102.9 mm long, 91.44 mm wide, and 57.15 mm high (that measurement is a rough guesstimate because how do you precisely measure a tortoises height...)

I’m very confused... He’s quite overweight on one scale and quite underweight on another. Can anyone offer insight?

 

[KarenSoCal]

Not being a smart***...forget the ratios. If he's eating, drinking, peeing, and pooping, he's fine. They grow at such variable rates...He'll grow when he wants to. ??

 

[wemakegreatpets]

Not being a smart***...forget the ratios. If he's eating, drinking, peeing, and pooping, he's fine. They grow at such variable rates...He'll grow when he wants to. ??

Thank you!

 

[ZEROPILOT]

Not being a smart***...forget the ratios. If he's eating, drinking, peeing, and pooping, he's fine. They grow at such variable rates...He'll grow when he wants to. ??

I tend to agree with that logic

 

[jsheffield]

I calculate my Torts' position relative to the "ideal" using the Donoghue Ratio (SCLcm3 x 0.191 = tWTgr) every month or two.

The formula makes sense to me and seems based on reasonable science, but I use it more as a benchmark than an absolute.

I wrote up a pdf document about the Donoghue Ratio to help me understand it when I first came across it.

I find comparing results to past measurements much more useful than the simple result... seeing trends in the health of my tortoises are much more useful to me than a single data point.

The ratio doesn't yield great data for all torts, just the ones it was designed around... my hingeback routinely scores underweight (I think because they're flatter than the species of torts used in establishing the ratio), but even so, comparing the data on him from month to month is useful (to me... I think).

I think at the end of the day, if your tort is eating and pooping and active and putting on weight, then you're in a good place, but I feel that having this sort of data is perhaps a bit more nuanced.

Jamie

 

[Markw84]

Not sure what type of tortoise you are talking about. I assume Russian from your avatar.

I do not use the Jackson ratio at all. For the past 30+ years I have always used a ratio I started doing back then of simply volume as if a cube in inches, divided by weight in grams. So - weight/ length x width x height. To get meaningful results, especially on smaller tortoises, you need to use a caliper to get accurate measurements. I use this on all my tortoises and all species. I look for a result between 7.5 and 9.0. The higher domed tortoises will be towards the higher end, the flatter and less domed tortoises more in the 7.5 - 8.0 range.

According to the method If I take your measurements, I would want a Russian tortoise the size you have at 270g.