The younger sailor was in his late teens or early 20s. Not much else is known about him, because he hadn't lived long enough for his habits to leave an imprint on his skeletal remains, Nielson-Green said.
The forensic investigators hope to identify the crewmen by comparing DNA samples from the bones with samples from descendants of Monitor crewmen, Nielson-Green said.
"They will be given a military funeral unless the family member chooses otherwise," she said. "We are optimistic that we will eventually identify them."
Jeff Johnston, historian for the Monitor National Marine Sanctuary, said he thinks the remains are those of the men who were trying to keep the Monitor's steam-powered pumps operating so other crewmen could be rescued.
"The pumps were the only thing keeping it afloat, and these were the last two guys to leave the boat," Johnston said. "Somebody had to keep the fires going."
The Monitor revolutionized naval warfare when it was launched in 1862 during the U.S. Civil War. The ironclad was loaded with ingenious technology, including a revolving turret that allowed the ship's gunners to aim their two 16,500-pound (7,500-kilogram) cannon without turning the entire ship.
In March 1862 the Monitor engaged in an epic naval slugging match with the Confederate ironclad Virginia near Hampton Roads, Virginia. Neither ship could inflict serious damage on the other, but the Monitor prevented the Virginia from breaking the U.S. Navy's blockade of Norfolk. That defense dealt a serious blow to Confederate hopes of winning the war.
Later U.S. Navy commanders decided to send the Monitor to South Carolina to enforce another blockade. But a vicious storm off the North Carolina coast caught the Monitor on the night of December 30, 1862.
The crew was ordered to abandon ship, and the U.S.S. Rhode Island, which was towing the Monitor, sent rescue boats.
Francis Butts, who had volunteered for duty aboard the Monitor only a month earlier, said he was alone in the turret when the ship's cat began "howling one of those hoarse and solemn tunes."
Butts said he removed the muzzle plug from one of the ship's cannons, pushed the cat into the barrel's 20-inch-wide (51-centimeter-wide) opening, and replaced the plug.
Butts wrote about his experience in 1885.
Johnston, the Monitor National Marine Sanctuary historian, thinks Butts's claim is a tall tale. While Civil War sailors often had pets aboard their ships, Butts is the only Monitor crewmember who ever mentioned a cat, Johnston said.
The historian notes that newspaper reporters of the day often wrote about ships' pets and that the press idolized the Monitor and its crew after the dramatic battle at Hampton Roads. "The crew was given a heroes' welcome everywhere they went," Johnston said. "If there had been a cat on board, I think a reporter would have picked up on it."
When Butts wrote about the cat two decades after the warship sank, the nation was undergoing a revival of "Monitor madness." Johnston speculates that this could have motivated the Civil War sailor to spin the cat tale. "In my opinion, Francis Butts told that story, because he needed a claim to fame later in life," Johnston said.
Still, it will be a while before investigators can determine whether Butts was telling the truth, since X-rays can't penetrate the thick barrels of the massive cannon.
The cannon are being treated for preservation, and it will be at least another year before investigators can remove the concretions that accumulated in their barrels during their long stay on the Atlantic Ocean floor.
Then researchers will finally see whether an unlucky feline did indeed go down with the Monitor.
Willie Drye is the author of Storm of the Century: The Labor Day Hurricane of 1935, published by National Geographic Books.
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