How can u find out how old a herman tortoise is?

Answers:
If it's wild caught then it's impossible. If it's from a person or pet store they should be able to tell you. Counting rings and lines on their shells are myths and do not work. If anyone tells you this is way, they're complete morons.

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The only reliable way is to watch it be born.

If you just want to know for fun, you can count the rings on the plastron (belly). It is not anywhere near accurate, but if you count them, then divide by 3 (or 4 if they are really close together) you will be accurate enough for curiosity's sake.

If you know the size, you can try a growth chart for Hermann's, although Icould not locate one to link you to.