I've once seen something like tamed vermin (not even sure on how I got it but I had no animal traps in) in the Units screen but I can't seem to locate it or view it at all.
Elf caravans like to bring these, in cages. If you can find it on the stocks screen, you can zoom to it from there. Otherwise, you can inspect all the cages at the depot.
Unrelated: you know what doesn't work? Trying to lure the goblin siege who are cowardly hanging around the edge of the map by bringing a tame tiger to a 1x1 pasture near the goblins. I figured the civilian leading the tiger would see the goblins and flee, and then the goblins would pursue the tiger. What acually happened was the civilian still kept hold of the tiger, and her baby in the other hand, and all three of them sort of waddled away from the one goblin who pursued them. The goblin got all three of them. Even though I de-zoned the pasture zone entirely, and even though the pen/pasture job was cancelled upon sight of the enemy, she never let go of that elfin' tiger.