Please take a look at this thread:
http://www.tortoiseforum.org/threads/oh-so-you-little-escape-artist-you.113453/
And this one:
http://www.tortoiseforum.org/threads/so-breaks-the-fence.113169/
In Aldabraman's photo thread it shows that he has added a new row of boards to the top of his fence, but I don't remember if he talks about why he had to do it.
Yes, one of his male Aldabras, the newest one I think, but his name slips my mind, Alpha maybe, started to climb the fence.