A T-Rex Who Loves to Smile

About this drawing

A friendly T-Rex like this one brings up a very funny question. Why did such a giant animal have such tiny arms? They were so short they couldn't even reach its mouth. Scientists have been scratching their heads over this for a long time.

Those little arms were small, but they weren't weak. They had strong muscles and sharp claws. Some experts think they helped a T-Rex hold on to things, or push up from the ground after lying down. Others think they might have been used to hold on to a mate. Nobody knows for sure yet!

There's another fun idea. When several T-Rex dinosaurs ate together, those giant heads and teeth could cause accidents. Maybe short arms kept them out of the way so they wouldn't get bitten. Or maybe its huge head just did all the work, so it didn't need long arms anymore.

Over millions of years, the head got bigger and the arms got smaller. Something similar happened with ostriches, whose wings can't lift them off the ground. The T-Rex made up for it with super strong legs. It walked on two feet and used its long tail for balance, a bit like a kid on a seesaw.

• dinosaurs
• t-rex
• funny dinosaurs
• preschool