I have many fond memories of playing this game! I remember spending a lot of time in the animal creator, letting my imagination run wild. I also remember getting frustrated writing in their bio sections with the Wiimote under a low character limit. My favorite animals to play with were the big cats, with bears as a close second. One animal I distinctly remember having was a bright yellow lion called Sunny. Here is Sunny Jr., a reimagining of him I have created in the PC version!
One specific memory I have is spending a day filling each available monkey slot with a randomly generated monkey. I then took them out in the enclosure a few at a time and tried to play with all of them. I think I did this because I wanted to see what kind of cool and different random animals I could get - maybe ones I wouldn't have thought to design myself. I chose monkeys because you can have more monkeys out at a time than any other animal. I also chose them because they weren't one of my favorites, and I wanted to at least do something with them. Also, as a little kid, we had a school project where we had to put together a posterboard talking about ourselves. I talked about how much I loved this game, and I cut out a piece of the manual to use in my project, which my parents told me I would regret (and I do).