Center Pets

So, I have a question for all of you:

Where do you draw the line of center pets?

My husbands center has a pet pig. I never would have dreamed it up, but it has turned out to be a fabulous addition!

We have a gecko, fish, and a turtle.

I have had so many rats I can't even keep count anymore. These are great, especially if you have a teacher who can train it. One of my rats was trained to wake the children up from nap. They loved waking up to that tickley little face next to theirs! The children who were real grumpy when they woke up enjoyed it the most! She would also play in the block area with them and we even had her paint with them one day (when we were talking about animal footprints).

I had a pet tarantula once too! This was also a very fascinating pet that the children loved!

I've heard of hamsters, mice, frogs, and birds. For the most part, this general rule seems to be something that is caged. Then this happened today.

So my question is:

Where do you draw the line at a center pet? Would it be okay to have a dog as a pet? How about a tortoise? Goat? Cat? Iguana? Tell me what kind of pets you have had.