There are apparently different ways to measure a tort (starting and end points). But if I measure Morla (they est her at =10 yrs old), I do it along her plastron, (so it's flat) but use the carapace ends for the start and stop points.
I have a fairly big girl whose grown from 5 inches long to about 7 inches long by 6.5 inches wide In four years; she’s a BIG eater. She’s probably a little larger now as she’s just had a growth spurt, I’ll have to check. She’s wild caught and was here for a while before we got her (runaway); vet estimates 15-20 years old. @Yvonne G has some big girls, they were some of the earliest imported into the United States but I haven’t seen her post their sizes for a while.
Size in tortoises aren’t relative to age, they are relative to how much they are eating. I expect some of it is also genetics.
They really don’t look different as they age; just a bigger version of the original. I never thought to take growth photos, the closest I have are below. In both she’s in her night box; if you look at her sleeping against the wall you can kinda see how much wider she’s gotten by checking how much closer she is to the wood divider. She’s outgrown an outside burrow and will outgrow the door to this box this year :/ but again, looks exactly the same. We can tell, obviously; it takes two hands to safely hold her now, compared to one. The onLy is that one of the white “dings” we see in wild caughts from all the scraping they do over rocks, popped off this year. She grew enough keratin underneath to pop off the old bone chip. You can barely see it in the second photo, I circled it in red.
I’ve not seen this 10-inch female mentioned above and now I’m very interested!
This is the biggest one I’ve ever seen; it’s a picture of one for sell. The big one is over eight inches long; the smaller is a bit small at five inches. You can see it’s really just a matter of size, although the big one has very pretty coloring and markings.