Ankylosaurus lived during the Late Cretaceous Period in what is now North America. This armoured dinosaur had bony plates covering its body and a heavy club at the end of its tail.

Though it's the most famous member of the ankylosaur group, it's not the best understood. Scientists still haven't found an entire Ankylosaurus skeleton. Some other types of ankylosaurs, such as Zuul, are known from many more bones.

But we do have enough Ankylosaurus remains to see that it may have been one of the biggest ankylosaurs.

When was Ankylosaurus discovered?

The first Ankylosaurus bones were found in 1906 at the Hell Creek Formation in Montana, USA. Barnum Brown led the fossil hunting trip - the same scientist who led the discovery of Tyrannosaurus rex a few years earlier.

These Ankylosaurus fossils weren't very complete. The distinctive tail club wasn't discovered until much later.

Barnum and his team found several pieces of armour, but they had separated from the main skeleton. Even today, nobody knows exactly how Ankylosaurus' back armour should be arranged.

Was Ankylosaurus aggressive?

We can't say for sure how any dinosaur behaved when it was alive. Scientists can only go on fossils and comparisons with living animals.

We know that as a plant eater, Ankylosaurus wouldn't have used its tail club to attack prey. It probably used the club to defend itself against big predators.

Being herbivorous doesn't mean Ankylosaurus was harmless. Many modern plant-eating animals, such as elephants and hippos, can be very aggressive and dangerous. We may never know whether Ankylosaurus was gentle in nature!

How did Ankylosaurus move?

This hefty dinosaur probably moved very slowly most of the time, although it might have been able to move faster when needed.

Ankylosaurus probably couldn't move its tail club up and down much, but could swing it powerfully from side to side - delivering devastating swipes to any would-be predators.

What did Ankylosaurus eat?

Experts think Ankylosaurus grazed on low-growing plants. It probably wasn't picky - eating many kinds of ferns, shrubs and fruit.

Ankylosaurus would've needed to eat around 60 kilogrammes of plant matter a day. That's about the same as a modern elephant.

Some scientists think Ankylosaurus might have been able to use its front limbs for digging. If so, perhaps it also ate roots and any other kinds of plant and animal matter it could dig up.

Were there any ankylosaurs without tail clubs?

Several members of the ankylosaur group lacked the bony tail clubs seen in Ankylosaurus and others such as Tarchia, but were otherwise still covered in armour.

These clubless ankylosaurs include Nodosaurus, Panoplosaurus and the British dinosaur Polacanthus.