If you are having a hard time finding spino's in their respective spawn zones (especially Ragnarok), kill all the fish in that area. They share the same spawn capacity and can be out spawned by coles! ( up vote so Rag players know!!!)
As far as I know, only 3 wild carnivores will aggro onto the sight of your spino, other Spinos, Rexes, and Gigas. You can probably outfight other spinos, outrun rexes, or outfight lower level ones, and outrun gigas. Very useful.