T. rex is some kind of king, so it's only right that he should have really kingly droppings. 'Coprolite' is the fancy name for fossilised faeces, that is, animal dung, or poo.
In 1997, the Royal Saskatchewan Museum sent Karen Chin of the US Geological Survey a rather unusual specimen that they had unearthed. It was large (44 centimetres by 16 centimetres by 13 centimetres), nicely tapered and quite heavy (7.1 kilograms).
It turned out to be a Tyrannosaurus poo, and twice as big as any other previously discovered carnivore's poo. For many years, the palaeontologists thought that T. rex had the biggest head of any dinosaur. One skull measured 1.5 metres long.
But in 1996, Carcharodontosaurus (meaning 'shark-toothed reptile') was discovered in Morocco. Its head was 1.6 metres long. Now the T. rex teeth were in a huge jaw, and powered by huge jaw muscles, so they could generate a massive bite force of an enormous 3100 kilograms.
Comparing this to today's animals, it outclasses the 1800 kilograms of bite force of a great white shark, the 560 kilograms of a large African lion, and is much greater than our pathetic human bite force of just 80 kilograms. On the other hand, T. rex had less bite force than the extinct ancestor of the great white shark, the gigantic Carcharodon megalodon.
This shark, 16 metres long and weighing up to 100 tonnes, could generate up to 18,000 kilograms of bite force.
T. rex had lots of teeth. The biggest tooth found so far is about 30 centimetres long. These teeth sat in a huge jaw, which was U-shaped at the front, not V-shaped like many non-tyrannosaur dinosaurs. The teeth right at the very front of the upper jaw was curved backwards, and had tips like chisels (like our front teeth).
The rest of the teeth were more robust. The palaeontologists often call them 'lethal bananas'. They were also serrated, with the serrations on the front and rear surface.