Finally laid the smack down on that damn Duramboros.  Bastard kept tunneling away, and then in the middle of the quest I accidentally shrunk my map and didn't figure out how to fix it for a good 5 minutes or so.  Felt so good smashing the jerks humps and then finally seeing him go down.  The bastard even tail whipped me off the waterfall at one point and I had to swim all the way back around.  
Anyway, I finally have a little buddy again!  Hooray!  (Even if it's not the same one.  When do I get Chacha back, by the way?  Am I going to be waiting a while?)  It also feels kind of cruel that one of the quest that pops up after the Duramboros urgent... is to hunt a Duramboros... in the same location.  I guess you won't have Kayamba sitting there being useless, but still.  Don't think I'll do that one for a while yet.