The Ballad of Big Al,[a] marketed as Allosaurus[b] in North America, is a 2000 special episode of the nature documentary television series Walking with Dinosaurs.

The Ballad of Big Al was like the other episodes of Walking with Dinosaurs made by Impossible Pictures and was produced by the BBC Studios Science Unit,[1] the Discovery Channel, ProSieben and TV Asahi.

The special begins at the University of Wyoming's Geological Museum, showing the bones of a sauropod followed by an Allosaurus named Big Al. After the ghost of Big Al wanders the museum passing by his own skeleton and a nest of fossilized eggs, the film then travels back in time to 145 million years ago during the Late Jurassic of Wyoming, showing an Allosaurus nest.

Three years pass, and a herd of Diplodocus are migrating across the Late Jurassic salt lake, heading for a nesting site to the south.

His presence however makes other dinosaurs around the pond nervous and the smell of blood he brings with him puts off a pair of Stegosaurus that were attempting to mate.

As the dry season turns to a drought, Al's limp from the fall gets worse and his right middle toe -which he broke in the fall- has become badly infected.

He is said not to have reached full size, dying as a mature adolescent and that the process of his fossilisation was so perfect it preserved even the injuries he sustained in his lifetime, including lumps where his ribs healed after their break and the raging infection on his middle toe.

The narrator concludes the special stating how Big Al, in death, represents a frozen moment in the fast and furious life of a carnivorous dinosaur.