This
species of the Ankylosaurids is one of two that are found in North America.
Ankylosaurus skeletal remains have been found in Montana, USA and Alberta,
Canada. They are most noted for their armored exterior and club tail, both of
which served as defensive mechanisms. The clubbed tail is actually several bones
that are fused together and massive, covered by a layer of skin. Ankylosaurus
grew to 33 ft (10 m) in length and were prevalent during the late Cretaceous
period. -- Text by:
Bob Simon