Originally Posted by Agent_Of_Chaos

You're right about the animal theme actually. Undertow was originally called "Animals" The track listing was as follows:

1. Rats (Intolerance)
2. Dogs (Prison Sex)
3. Okapee (Sober)
4. Mollusks (Bottom)
5. Crabs (Crawl Away)
6. Cats (Swamp Song)
7. Pigs (Undertow, reason Undertow is on pig's side in booklet)
8. Lions (4*)
9. Locusts (Flood)
10. Sheep (Disgustipated)

They had to change it though because Maynard stumbled upon a Pink FLoyd album that happened to be called "Animals" already. Surprisingly enough, it included songs with the names "Dogs", "Sheep", and "Pigs". The coincidence got even weirder when they saw the cover art of a pig floating above a factory: Danny Carey had suggested the very same thing for the Tool album. So the album title itself and all the song names had to be changed so Tool wouldn't look like ripoffs. They were still able to keep the pig on the back cover though, so Undertow was considered a success.