In our Family Archives is a bound set of "Harper's Weeklys" kept throughout the War by an Ancestor who lived through it; there is a detailed report contained therein which I remember reading once regarding the Monitor's fatal last voyage.

For some reason, one thing that touched me a lot in that article was the account of one of the last survivors to leave the foundering ironclad; the ship's cat was wailing like a banshee, apparently all too aware of it's imminent fate (as animals often seem to know better than humans); annoyed by the wailing, the Sailor picked up the feline, stuffed it down the muzzle of one of the 11" Dahlgrens and plugged the big cannon's mouth with a "tompion", which was normally inserted into the muzzle to keep the elements out of the bore. It is assumed that the cannon became the poor cat's seplechure for the next 140 years or so.
I can't help but wonder if they find a feline skeleton still reposing in the barrel of one of the Monitor's two long - silent Dahlgrens.

Make that casualty list 16 Union Tars and a cat.