and a Moose:

The Muses (Mousai or Moisai) were a group of goddesses whose chief cult center was located at Mt. Helicon, Boetia, in ancient Greece.  They were the patron of all liberal arts and sciences as well as the gymnasia, since physical training was an intergal part of the ancient Greek educational system.  

A Moose (alces alces) is the largest member of the deer family with a shoulder height of 1.5 - 2 meters, weighing 820 kilos.  

The two should not be confused and, in fact, need to be kept completely distinct in cognitive hierarchies to avoid systematic error.  

A Muse, has a particular discipline over which she reigns.  Calliope (not to be confused with a cantalope) means She of the beautiful voice and, thus, reigns over Music.  

Any particular Moose doesn't reign over anything and, during the summer, shuffles along from lake to lake eating water plants.  

The Muses were canonically limited in number to 9.

Moose are limited to the ecology of northern America and Eurasia.  

A Muse was seldom shot, had its head cut-off, mounted on a board, and nailed to a wall.

For a Moose, this process is less common than formerly but is still known to happen.

The common feature providing the maximum source of confusion, lies in the fact Muses, tho' shy, can oft be found dancing in a woodland glade.  A Moose is also found in woodland glades and are also shy.  A Rule-of-Thumb field test, to determine which is which is:

If it's a semi-clad young woman ascending into the heavens there is a high probability you have encountered a Muse.  If it's big, hairy, shaggy, with huge horns, and trampling you to death it is most likely to be a Moose.

I sincerely hope this diary has been of some value in forestalling confusion and misapprehension.