Dimensions 10,30 x 20,10 x 18,0 cm (W x D x H) Age Recommendation 4-12 years The Giganotosaurus looks very similar to the T-rex. 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.