There's lots of meat in there (protein) - but it's also very fatty. The tail is just a big paddle and as you'll notice with your fingers, the muscles that operate them are in the arm. So with the beaver the operating muscles are in the body.
I was going to suggest a similarity to bacon - but you lucky Europeans still have real bacon. Here we search for a package that has some streaks of meat along with a solid gob of fat...
A big problem with the idea of eating beaver is that no-one traps them much any more and so the population has exploded. The ones trapped are those that have been pushed out and are busy building a moat around someone's house etc. They might be able to get by with eating about any type of tree, but eating something that tastes like pinesol isn't too appetizing. Besides the fat content, that's probably the main reason people choke on eating beaver now.
