Do you know the difference between elk, moose, caribou and reindeer?
Those four names refer to three different species in the deer family, but which is which depends on where you are in the world, or more specifically: whether you are North American or not.
1) The animal called elk in most parts of the world is called moose in North America. This is the equivalent to the Scandinavian älg or elg. There are subspecies of elk/moose in different areas of the world, with differences in size and colouring, but it is the same animal. It is generally the largest of the three and its horns are distinctly different in shape.
2) The North American elk is a whole different type of deer (Cervus canadensis), and known by its Native American Shawnee name wapiti in the rest of the world, which means "white rump". It is native to North America and East Asia. Nowadays it is also raised on ranches as semi-domesticated deer.
3) The animal named reindeer is known as caribou in North America, but both names refer to the same animal (Rangifer Taranbus). There are subspecies that differentiate the two with differences in size and colouring, but they are considered to be the same animal. It is the only deer where both the females and males grow antlers.
The difference between the 1) elk/moose and 2) elk/wapiti is explained here.
The differences between the 2) elk/wapiti and 3) reindeer are somewhat detailed here.
IMAGES: Moose by Richardfabi, ALL IMAGES PUBLIC DOMAIN VIA WIKIMEDIA COMMONS