The only way we're ever going to really know what the dinosaurs looked like is when someone finally pulls a John Hammond on some isolated tropical island.
Then you know nothing about animal behavior and also interspecies conflicts then. Caracharodontosaurs have different prey items and they are specialized for sauropod hunts. In most cases, smaller predators tends not go after large predators because it is not beneficial to attack something larger and dangerous. Spinosaurus is clearly top predator because no other predators would make a meal out of the largest theropod.You also forget that Spinosaurus was not the apexpredator in that environment. With a sail, Spino would be easy prey for Carcharodontosaurus.
Could also be that only female Spinosaurus had such a hump to storage nutritions during breeding season. The problem we have is, that the only existing Spinosaurus got destroyed and we only have shattered remains.maybe spinosaurus was sexually dimorphic. we only have one partial skeleton and scattered fragments. If the female lacked the sale it wouldn't be an issue. the sail could be a display for males. just look at all the other obscure junk male animals have evolved to attract females. With scattered remains who's to tell what sexual differences there were. I know one example is the fabrosaurs. They were initially thought of as a seperate species. They had an almost identical bones to an animal called heterodontosaurus. when complete skeletons were found the only real difference was the fabrosaurs lacked a pair of tusk like teeth in the heterodontosaurs. This shifted the fabrosaurs to being considered female heterodontosaurs as they were frequently found amongst each other
Spinosaurus's jaws are far from being weak...after all he feeds on 3-8 meters long heavily armoured fishes and the fish weren't his only prey items. The evidence shows that Spinosaurus feeds on smaller dinosaurs as well.Spinosaurus has weak jaws and is specialized on fish. He would be easy prey for a Carcharodontosaurus. I don´t see where Spinosaurus is dangerous.
Spinosaurus's jaws were more robust than an Indian Gharial's jaws, and also some giant fishes were heavily armoured so you need a sturdy jaws to handle these armoured fishes. Funny thing is there are evidence says that Spinosaurus was less aquatic than his relatives so it suggests that Spino do not feeding on fishes all times.Spinosaurus has weak jaws like a gharial. He was a fish eater that occasional did bite into a small dino or carcass.
Could also be that only female Spinosaurus had such a hump to storage nutritions during breeding season. The problem we have is, that the only existing Spinosaurus got destroyed and we only have shattered remains.