Spinosaurus holds the world record for being the largest known carnivorous dinosaur, given its impressive length and 9.9-ton build. The imposing dinosaur’s most unusual feature was its large sail Whenever Spinosaurus would arch its back, the sail, made of lengthy spines covered with skin, would rise into the air. Paleontologists continue to debate its function, but most suspect the sail helped to regulate body temperature and was used to woo the opposite sex or to scare off competing males. It’s no wonder Spinosaurus often makes film appearances, since this dinosaur flashed a million-dollar “smile.” While most carnivorous dinos had curved teeth, the teeth of Spinosaurus were straight and probably functioned like knives, skewering often-slippery prey. Like modern grizzly bears, Spinosaurus probably spent a lot of time grabbing fish in, or near, water. A dinosaur of such girth, however, likely did not subsist on an all seafood diet. It probably killed and consumed smaller dinosaurs too, along with scavenging flesh from corpses. Such feasting would not have posed a challenge, since Spinosaurus possessed what was arguably the longest head of any known carnivorous dinosaur. Measuring close to 6 feet in length, the head featured a narrow snout — all the better for showcasing its straight teeth — with tiny ears on either side. Scaly skin covered its neck. Few enemies probably dared to challenge Spinosaurus, considering that its large body could look even twice as big once its sail was instantaneously raised, scaring most would-be attackers. Humans turned out to be a significant threat, to its fossils at least, since a World War II bomb raid destroyed the first known Spinosaurus remains, which were collected by German paleontologist Ernst Stromer. Luckily, Stromer documented his find or else no one would ever have known about the distinctive dinosaur.