All I know is to not try and run from one it won’t work they can run 5 times faster than you. but what I do know is that you have to use a giant trapdoor so number 1. Build your house on the bottom of a hill. 2. Find a spinosaurus then make it run after you but make sure your running speed is at like 300% . 3. Jump down the hill into your house then open the small door not the dinosaur gates. 4. Tranquilize it then badda bing badda boom you got yourself a spinosaurus.
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!!!)