[quote=@Oraculum]
On that note, how widespread are the Slugs? They seem to have started out as Deepwoods creatures, but must have propagated a fair bit to be a common sight as far south as Tallgrass. 
[/quote]

They are specified as 'Forest Creatures'. While, yes, originally this meant around the Deepwoods, they were created before sentient life, so would have had plenty of time to travel. And since the early days Galbar has been covered in trees (in most places on Earth that aren't deserts, if there aren't lots of trees it's because Civilisation has cut them all down), these forest creatures would have probably spread quite far.