(CNN) -- The majestic bald eagle rises from its trainer's arm, launches itself into the night air and completes a circuit of the stadium to the raucous cheers of thousands of football supporters.

That has been a common sight in the Italian capital for the past few months, after Rome club Lazio "signed" the bird of prey on a €125,000 ($170,000) one-year deal from Portugal's Benfica -- copying a tradition employed for decades by the Lisbon side. The eagle is a prominent feature in the crests of both teams.

"It looked like a great idea to everyone," Lazio owner Claudio Lotito told CNN. "The eagle is very important for us, it is our history.

"It is something that can move the hearts of the fans and make them aware of who we are, to make them feel proud of the values of our club, and to represent in the best way our spirit of freedom."

The arrival of "Olimpia" -- named via a public poll and representing the club's blue-and-white Olympic colors -- has coincided with Lazio's resurgence in fortunes this season.

The September 22 home match against AC Milan marked the bird's debut flight at the 82,000-capacity Stadio Olimpico, but a leading animal rights group has questioned whether such a publicity stunt can be justified given the unnatural pressures put on the eagle.

"Eagles and other live animals don't belong at noisy athletic events. Most professional sports teams use human mascots, who, unlike scared, spooked and vulnerable animals, can safely interact with fans," PETA spokesperson Sandra Smiley told CNN.

"Birds and other animals can become severely distressed by the crowds, the high spirits, the misbehavior, the confusion and the racket at big sports events."

Lazio officials chose not to make Olimpia fly before November's home derby defeat by Roma -- traditionally a fiercely-contested clash between clubs who share the same stadium.

"It was just a precaution. It was only for that match, in order not to spoil our rival's fans and not to cause any disorder," Lotito said.

"It was suggested by the police the days before the match and we completely agreed. All in all, there is not any worry that a crowd could be too loud and bother the eagle, because the bird has been specifically trained for these kind of situations.

"The derby was, and will stay as, an exception. This eagle is our symbol. And unless there is some complication, we intend to keep the eagle for a long time."

So is there a place for live animal mascots in these times of hi-tech sporting entertainment?

"Very few sports teams in Europe still use live animals as mascots," Smiley said. "This reflects the fact that public sentiment is rapidly moving away from the antiquated notion that animal displays are acceptable or fair to the animals.

"Unlike star athletes, animal mascots don't get star treatment -- their almost constant confinement ensures that they are sad, lonely, bored, depressed and deprived of all that is natural and enjoyable to them."

Animal mascots became popular in English football around the start of the 1900s, says Alexander Jackson of the National Football Museum.

"Manchester United captain Charlie Roberts was given a goat by the manager of a traveling circus whom he was friendly with," Jackson told CNN.

"Apparently, after a home win Roberts would take the goat out to the pub with him for a drink, and it actually died after one drink too many after Manchester United won the 1909 FA Cup."

Jackson says the vogue for animal mascots slowed down in between the two World Wars and shifted towards suited-up humans, as is generally the case these days. But there are exceptions.

At the 2010 World Cup finals in South Africa, Nigerian fans complained after not being allowed to take painted live chickens into stadiums.

German soccer club Cologne has paraded its goat mascot Hennes at home games since the first incarnation was donated by a carnival ringmaster in 1950.

And in the United States, there is a strong tradition of using live animals such as tigers, buffaloes and horses in the college gridiron football scene -- much to the dismay of groups like PETA.

Louisiana State University has had a tiger as its mascot since 1936, and visiting teams have to pass the caged beast on the way to their locker room. Mike VI, a Bengali-Siberian hybrid, lives in a $3 million on-campus habitat, while rules were put in place to protect the animals after the third incarnation died on active duty in 1976.

"Many of the animals chosen as mascots are animals who would naturally roam or fly over many miles of territory, live in social groups, hunt, and raise their young," Smiley said.

"Many animals used as mascots also suffer injuries. Bevo, the steer used by the University of Texas, endured at least two painful brandings, and two mascot goats used by the United States Naval Academy died from poisoning."

However, Lotito said Olimpia -- a five-year-old male -- was treated as a "noble."

"A team of three Spanish people is around her. They care a lot about her, in every way," said the 53-year-old, who has been president since saving the club from bankruptcy in 2004.

"The eagle is eating like a noble person -- the staff is feeding it only with things like salmon or chicken off the bones. The eagle lives in Formello, the town outside Rome where we have our training camp, and it has his own house.

"Sometimes fans can see it when they come along, because every day the eagle is flying for a few hours around the camp. But we are planning to schedule daily visits for all the visitors, especially for all the kids that come to the camp and ask about it."

Lotito admitted that animal rights groups had protested against the club's decision to introduce the eagle, but said Lazio had received permission from all but one regional body.

"There is still one last tribunal that has to pronounce his sentence. It is expected in the next weeks, but everything is regular. So we have to wait for it, but we have nothing to fear."