In my current fort I thought I would be clever and set up a line of cage traps through a very unusual formation between two mountains - it's like a 2-tile-wide straight chasm down to ground level. (I call it Armok's Sundering, since it looks like someone took a BFAxe and sliced right through the mountain.) And because of the layout, to get from one side of the map to the other, you have to either go over the mountain or walk through the Sundering. (And we all know how goblins like to take the shortest path...)
Well turns out we have BADGERS. And they like to follow each other. So what's that mean? It means I now have cages full of badgers. Not Giant Badgers, sadly.
Is this a good thing? Well sorta. On one hand they make good goblin fodder. I modded so they could be War Badgers. They aren't really any better or worse than war dogs in my experience.
On the other, they breed like cats and they mature quickly... Seriously, you will have a badgersplosion on your hands pretty quickly once you get a half dozen or so mature badgers.
And on the gripping hand, it means a near-continuous supply of reasonably effective front-line defense for your fort as your population booms, gets decimated by ambushes, recovers and booms again, etc etc.
I likes War Badgers person'ly. I don't even bother caging or chaining them. I make a pen by the front entrance and assign a dozen or so and they politely stand around waiting for a thief or ambush to try to slip by.