there is actually a limit on signatures that is meant to prevent people from having super long sigs but we just don't enforce it terribly:

from the FAQs: "...signatures be limited to 6 lines of text without a banner graphic on a 1024x768 resolution screen or 2 lines with a banner on the same resolution."

in order for your script to work in the signature area it would have to be compatible with our forum software, or be written in bbcode. you couldn't just plug it in like it is now...

in each user's profile there is an area called "My Collection"--that was put in place to help alleviate the need for listing your whole collection in your sig--you can list everything there and people can click on your profile to see it. of course, another way to shorten your sig is to list everything separated by semi-colons instead of making a separate line for each animal/species/etc.