Size and Weight:
In most ways--except for the prominent ridge along its back, from which its name ("high-spined lizard") derives--Acrocanthosaurus was a typical large theropod dinosaur, with big, powerful legs, equally powerful jaws, and relatively stunted arms. The big difference is that, while huge predators like Tyrannosaurus Rex and Giganotosaurus dominated the later Cretaceous period, Acrocanthosaurus was an apex predator of the early Cretaceous, that is, one of the biggest meat-eating dinosaurs of its time and place.
As with other sail-backed dinosaurs, such as Spinosaurus, experts are unsure about the function of Acrocanthosaurus' distinctive back ridge. It may have served as a storage place for fat (like the hump of a modern camel), as a temperature-control device (depending on whether Acrocanthosaurus was cold- or warm-blooded), or as a sexual display (males with bigger, more prominent ridges winning the opportunity to mate with more females).