These con blue to a level 35 and still con blue to a level 40. They start conning green around level 40.
Loot: Common: Bat Fur, Bat Wings and up to a few plat No other loot that I found -- and I hunted the mines for 4 levels.
Notes: All of the four mine creatures (tar goos, scuttle bats, scuttle rats and crytal spiders) are KOS but have a very low aggro range. Only the spiders swarm. You can hit a bat that is sitting right on top of a rat and pull only the bat. I don't know if this will help to determine level but while they were green to the 50th level characters who came down for a quest PC, they still attacked them.
ps....they are called Scuttle bats and Scuttle rats, not shuttle....FYI