There is a lot of evidence pointing towards the idea of the Spinosaurus being semiaquatic. According to Paul Sereno, paleontologist at Chicago University, there are lots of features of a Spinosaurus that are semiaquatic.
- Their nostrils were small and located in the middle of their skull, which allowed them to breathe while their heads were semi submerged in water.
- They had neurovascular openings at the end of the snout, similar to that of a crocodile or alligator, which probably allowed them to sense movement in water just like crocodiles and alligators.
- Their teeth were huge, slanted, and interlocked at the front of their snout, which was ideal for catching fish.
- They had a long neck and trunk, which made it almost impossible to walk on two legs on land, but would have worked well for navigating water.
- They had powerful limbs with claws that made it easy to catch prey.
- Their short hind legs and small pelvis could have been helpful for swimming.
- They had dense bones that lacked marrow cavities which lead to more buoyancy control.
- Their feet had long bones and long flat claws similar to that of shorebirds. It is possible they may have even had webbed feet.
- Their tails had loosely connected bones, which would have been helpful to propel in water.
- They had a giant "sail" on their backs that would have made them visible while in water.