The decapitated heads of defeated Roman gladiators who competed in London 2,000 years ago were thrown into an open pit near the city walls and gnawed on by dogs, a new report suggests.

The skull parts, and a part of one leg bone, discovered 25 years ago, belong to about 40 young men around the age of 30. "We don’t know where the rest of them are," Rebecca Redfern, curator of human osteology at the Museum of London, told NBC News.

Redfern's new analysis shows evidence of injuries that have healed — in bones from otherwise healthy humans — suggesting that the men were engaged in violent activities, perhaps as gladiators in Roman Londinium between 70 and 200 A.D. They may also have been victims of the Roman practice of head-hunting, when soldiers brought back just the heads of warriors they defeated....