I figured dolphins were in that sweet spot where they were smart enough to be curious about exploring the external world, but not so smart that I’d have to worry about them realizing I was manipulating them and revolting against me the way humans might. I did consider crows and parrots as alternative options, but I didn’t want to use animals that small because I didn’t want to have to worry about the loss of knowledge every time one of the smarter ones gets eaten by a predator. In retrospect, elephants might actually have been a better starting choice… wish I’d thought of that before they went nearly extinct.