Although Oldcroghan man is missing his head and lower limbs, the team estimates his height at six feet six inches (198 centimeters), based on his arm span.
"That was a shock to us," Mulhall said. "He's probably the tallest bog body known from Europe."
Had the two bog men met, Oldcroghan man would have towered over Clonycavan man, who measured just 5 feet, 2 inches (157 centimeters) tall.
Perhaps to compensate for his short stature, Clonycavan man coiffed up his hair using an early hair gel.
"Naturally enough, he wanted to make himself look grander," Mulhall said. "It's a bit like someone wearing platform shoes."
Analysis of the substance by archaeologist Stephen Buckley from the University of York in England showed the gel was made of vegetable plant oil mixed with resin from pine trees found in Spain and southwest France.
The study team says the hair product is evidence of Iron Age trade across Western Europe.
While both bog men appeared to be aristocratic dandies of their day, they still met horrible deaths.
Oldcroghan man shows signs of cruel torture before he was beheaded.
"He was stabbed, his nipples were sliced, and he had holes cut in his upper arms through which a rope was threaded in order to restrain him," Mulhall said. He was also cut in half across the torso.
Meanwhile, Clonycavan man suffered three axe blows to the head, plus one to his chest and was also disemboweled.
"There was definitely an attempt to use several different methods to traumatize and torture the men," Mulhall added.
Similar evidence of grisly murders has been seen in other bog bodies found in Britain, Denmark, Germany, and the Netherlands.
For instance, Lindow man, displayed at London's British Museum, was struck twice on the head, garroted, and had his throat slit from ear to ear.
Various explanations have put forward for such bogland killings. These include punishment for breaking ancient codes of honor.
In the case of the two Irish bog men, the study team says they were probably used as sacrifices to pagan gods.
Ned Kelly, keeper of Irish antiquities at the National Museum of Ireland, suggests the bodies were offered to fertility gods by kings to ensure a successful reign. The victims were possibly political hostages.
Kelly says the bodies were placed on the borders of tribal boundaries "to ensure a good yield of corn and milk throughout the reign of the king."
More than 35 scientists worked on the Bog Bodies Project, which also revealed that Oldcroghan man's last meal consisted of buttermilk and cereals.
"We got a good overall account of these people both during their lives and at their deaths," Mulhall said.
The bog bodies will go on display at the National Museum of Ireland in Dublin in May this year.
Details of the finds are outlined in a television documentary to air on the BBC in Britain this Friday.
Free E-Mail News Updates
Sign up for our Inside National Geographic newsletter. Every two weeks we'll send you our top stories and pictures (see sample).
SOURCES AND RELATED WEB SITES