They swim out to sea in shoals and feed exclusively on seaweed which grows on the bottom at some distance from shore.

The animal swims with perfect ease and quickness by a serpentine movement of its body and flattened tail, its legs meanwhile being closely pressed to its side and motionless.

This is also the method of propulsion of crocodiles when swimming.
"The carnivorous or flesh-eating dinosaurs that lived on land, such as _Allosaurus_ and _Tyrannosaurus_, were protected from foes by their sharp biting teeth, while the land-living herbivorous forms were provided with defensive horns, as in _Triceratops_, sharp spines as in _Stegosaurus_ or were completely armored as in _Ankylosaurus_.
Trachodon was not provided with horns, spines or plated armor, but it was sufficiently protected from carnivorous land forms by being able to enter and remain in the water.

Its skin was covered with small raised scales, pentagonal in form on the body and tail, where they were largest, with smaller reticulations over the joints but never overlapping as in snakes or fishes.

A Trachodon skeleton was recently found with an impression of the skin surrounding the vertebrae which is so well preserved that it gives even the contour of the tail as is shown in the illustration (fig.