The remains of sausage dogs were found in the 2,000-year-old drains of the Colosseum.
Archaeologists said they might have been made to fight bears or perform acrobatics in ancient Rome.
The bones of lions, bears, and ostriches were also found, along with remnants of spectators' snacks.
Packs of sausage dogs might have been made to fight larger animals like bears or perform acrobatics in the Colosseum in ancient Rome, archaeologists have said.
Archaeologists said they found the remains of small dogs similar to dachshunds for the first time while excavating the drains of the iconic 2,000-year-old amphitheater, The Telegraph reported.
"We found many bones from dogs which were similar to the modern sausage dog," Alfonsina Russo, director of the Colosseum, told The Telegraph.
"They were less than 30cm [11.8 inches] in height. We think they may have been used to perform acrobatic tricks, just as you would see in a circus today. Or it may be that they were used as part of staged hunts or even pitched against bears and animals like that. We don't know for sure."
"Venatio" was a type of entertainment in ancient Rome involving various animals being pitted against each other in fights or being trained to perform tricks.
The dogs would have been ancestors of sausage dogs rather than true dachshunds, the paper noted.
The modern dachshund breed emerged in early 18th century Germany and was developed to go down holes and hunt badgers - Dachs means badger in German. They were "bred to be an independent hunter of dangerous prey, they can be brave to the point of rashness," according to the American Kennel Club (AKC).
The Colosseum archaeologists also found the bones of large dogs, leopards, lions, bears, and ostriches in the ancient drains.
The discoveries were made during a year-long study, during which archaeologists trawled through 70m of drains and sewers underneath the Colosseum, which could host up to 50,000 spectators.
Along with the animal remains, they also found the remnants of snacks that spectators, including fruits, nuts, and olives, would have eaten.
They also discovered more than 50 bronze coins from the late Roman period and a silver coin to commemorate the rule of the emperor Marcus Aurelius from around 170-171 AD, who was popularized by the movie Gladiator, per The Telegraph.