You can fight a wild giga with a high lvl raise. Must have asc or mc saddle and must be imprinted to the giga. Then go wreck anything you want basically!
These things (when tamed) take HUGE fall damage. Though if you are falling on it and have time, quickly press the dismount button. The dino will take 0 damage from the fall, you might die from the fall but giga will be fine. (Works on any dino)