The remains of 80 men were discovered on the land in York in 2004, but only now have the gruesome bite marks inflicted by a lion, tiger or bear been revealed by experts.
Initially it was thought the skeletons, some of which were found where a patio was to be laid, were the victims of a Roman cult because they had been beheaded while still alive.
But now it is believed that the bizarre cemetery found on the site under Driffield Terrace, near The Mount, was part of the world's best -preserved Roman gladiator graveyard.
Researchers, who have been forensically examining the bones since they were found, say the skeletons feature marks that reflect the violent manner in which the individuals died.
Kurt Hunter-Mann, a field officer at York Archaeological Trust who is leading the investigation, said bite marks on one of the skeletons helped steer the team to their latest theory.
The skeletons were also found to have "arm asymmetry", meaning one arm was larger and more developed than the other, indicating training with weapons from an early age.
Mr Hunter-Mann said: "One of the most significant items of evidence is a large carnivore bite mark – probably inflicted by a lion, tiger or bear – an injury which must have been sustained in an arena context.
"Other important pieces of evidence include a high incidence of substantial arm asymmetry – a feature often mentioned in ancient Roman literature in connection with a gladiator.
"There are also some healed and unhealed weapon injuries, possible hammer blows to the head – a feature attested as a probable gladiatorial coup de grace at another gladiator cemetery, in Ephesus, Turkey."
The research, which features in a Channel 4 documentary, Gladiators: Back From The Dead, has involved a large team of experts who have worked tirelessly over the last few years.
After careful study it has been revealed that nearly all the skeletons have features consistent with gladiators. The majority were male, very robust and mostly above average height for the time.
Mr Hunter-Mann added: "The arm asymmetry would also be consistent with weapons training that had already started in teenage years, and we know from Roman accounts that some gladiators entered their
profession at a very young age."
The skeletons date from the late first century to the 4th century AD.
All the individuals were buried with some respect despite being headless, and 14 of them were interred together with grave goods to accompany them to the next world.
The team said the most impressive grave was that of a tall man aged between 18 and 23, buried in a large oval grave sometime in the 3rd century.
Interred with him were what appear to have been the remains of substantial joints of meat from at least four horses possibly consumed at the funeral – plus some cow and pig remains.
He had been decapitated by several sword blows to the neck. After burial, a low mound of earth, up to a metre high, appears to have been placed over his grave.
Mr Hunter-Mann also said many individuals found in York came from different parts of the empire, which is consistent with a gladiatorial interpretation, but it was necessary to keep an "open mind" about the skeletons.
He said: "At present our lead theory is that many of these skeletons are those of Roman gladiators. So far there are a number of pieces of evidence which point towards that interpretation or are consistent with it.
"But the research is continuing and we must therefore keep an open mind."
Additional research has also been carried out by forensic
anthropologists at the University of Central Lancashire.
Dr Michael Wysocki, senior lecturer in forensic anthropology and archaeology at the university, said: "These are internationally important discoveries. We don't have any other potential gladiator cemeteries with this level of preservation anywhere else in the world."
Gladiators: Back From The Dead is on Channel 4 on Monday June 14 at 9pm.