A bit of a weird question, but I was told this by a tourist guide at Topkapi Palace, and he had a little print of this painting (http://en.wikipedia.org/wiki/The_Tortoise_Trainer). Does this have any basis in reality, and if so, where would such a strange tradition have originated?
The second paragraph of your own source states clearly:
"Osman Hamdi Bey cleverly satirises the slow and ineffective attempts at reforming the Ottoman Empire, depicted through the attempts of an anachronistic historical character to train tortoises."
It's just a metaphor.