Giga has several times more bite force and a much more dense muscle structure in the neck. While Spinosaurus was strong, especially with the whole water dwelling thing, it was mainly for catching, killing, and eating fish and other marine animals. Rarely would Spinosaurus venture out to eat other large dinosaurs.
Giganotosaurus on the other hand sits at the top of the food chain during its time, the late Cretaceous. It would be possible for the two to clash since they were active during the same period of time, but unlikely since they were on different parts of ‘Pangea’ at the time. Certain carnivores did migrate along with herds of herbivores, so I guess it could happen. But like I said, unlikely.
I’d have to give this one to the Giga. The strength and versatility advantage is just too great. If the Spino could get the Giga into the water, then yes, the Spino has a good chance. But it’d need to rely on slashing and bleeding to wear it out even then. A biting Spino is a dead Spino when it comes to large carnivores.
The same applies to the Tyrannosaurus fight in JP3. Anyone that knows ANYTHING about dinosaurs will tell you that a Spinosaurus isn’t going to win a land-based fight against a Tyrannosaurus unless there’s a water advantage present. That movie was funny, soon as Jr had a hold on the Spino’s neck it was over. The pressure alone would’ve snapped that poor Spino’s neck, and then he started chomping on the neck. Not only are the esophagus and trachea severely damaged, but the bones are actively being crushed and bent.
