Welcome to BrainStuff, a production of I Heart Radio.

Hey there Brain Stuff, Lauren Vogelbaum here.

They lived about 30 million years apart and never set foot on the same continent.

Yet, Giginatosaurus Carolini eye is always getting compared to the world's most popular dinosaur, the beloved and well-known Tyrannosaurus Rex.

Tyrannosaurus Rex has been a media darling since arguably 1906

when the New York Times called it the Prize Fighter of Antiquity. Named just one year prior, this big beast was already

making a splash over at the American Museum of Natural History in Manhattan. Today, we know that an adult T-Rex could stand 12 feet or about 3.5

meters tall at the hip and measure 40 feet or 12 meters long. As such, Tyrannosaurus was one of the

largest predators to ever walk the earth.

But hold your horses.

A handful of other meat-eating dinos rivaled or possibly exceeded these creatures in size.

Giginatosaurus belongs to this elite group,

and it's part of a dinosaurian mystery that's never been solved.

T-Rex and Giginatosaurus were both representatives of the Therapoda clade, a clade being a group of organisms

that includes a common ancestor species and all of its presumed descendants.

Hollowboned and bipedal, the Therapods were and are a highly successful bunch.

On the list of documented Therapods, you'll find every carnivorous dinosaur ever discovered,

quite a few plant-cobling species, and all birds living and extinct.

The last non-avian dinosaurs were wiped out at the close of the Cretaceous period,

an expansive geologic time that lasted from 145 to 66 million years ago.

Its conclusion marked the end of the Mesozoic era, sometimes called the age of the dinosaurs.

Tyrannosaurus rex lived in North America during the twilight of the Cretaceous,

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