Hm. Is it strange that my only grievance is that the Dire Beaver having a thinner tail means that it doesn't really live anything like a real beaver would? The tail is instrumental in helping them to build their damns...

I'd rather see it with a proper beaver-like tail, which it might use to send foes flying. Maybe up it to size Large and give it the Awesome Blow feat for use with a tail slap?

Just thoughts.