GiganotosaurusSchleich 15010 Giganotosaurus. The Giganotosaurus looks very similar to the T rex. Both were dreaded hunters, had very short arms, walked on two legs and had a large skull. However, the Giganotosaurus lived much earlier and was at home in North America, whereas the Tyrannosaurus Rex lived in South America. Fun Fact: The Giganotosaurus became 12 13 metres long, but its brain scarcely 30 cm big. *Movable lower jaw. Approx: 10. 3 x 20. 1 x 18cm (LWH)