A butterfly counts under the "other Perl mascot" option.
As for the others, like I said, I just can't list all animals, because if there's too many choices then people don't read them.
Also, if I have too many choices, the pollsters won't post the poll in first place. (They have a good reason for this: the poll takes up nodelet space in the default configuration.) This one is already pushing the limits. Just look at what they've done with my sports poll: down from 34 optionsto only 19.
Update: it's also useful that missing options start a conversation under the poll thread so we learn more than by just adding all options.