The three-year old, known only as M49, was captured Sunday in the Val Rendena valley in the Trentino region in northern Italy after it was spotted several times approaching inhabited areas.
But in a getaway compared by Italian media to Steve McQueen's exploits in the 1963 WWII film “The Great Escape”, M49 went on the lam Saturday after scaling a four-metre (13-foot) high and 7,000 volt electric fence.
“Run bear, run!” said one user on Twitter as the #fugaperlaliberta (#escapeforfreedom) hashtag went viral.
Three teams from the state forestry corps with sniffer dogs were set on its trail.
The search was complicated by the fact that the bear's tracking collar was apparently removed after its capture.
“If M49 approaches inhabited areas, the forestry service is authorised to kill it,” said Maurizio Fugatti, governor of the Trentino region.
“The fact that the bear managed to climb over an electric fence with seven cables carrying 7,000 volts… shows how dangerous it is,” he said.
But Environment Minister Sergio Costa was quick to countermand that order. “M49's escape from the enclosure cannot justify an action that would cause its death,” he said.
'Escape genius… superhero'
Farmers' association Coldiretti claimed the bear had approached inhabited areas 16 times, and killed 13 farm animals.
WWF Italy ridiculed the region's efforts to deal with the bear.
“A solid electrified fence with adequate power is an insurmountable barrier even for the most astute bears,” it said.
“Obviously the structure was not working properly, since bears do not fly.”
It was particularly serious that the collar had been removed, “making it even more difficult to track”, it added.
The global conservation group insisted “its danger to people is still to be demonstrated.
“At most, it can be considered problematic for causing economic damage to farming activities, following the failure to adopt appropriate prevention tools,” it said.
M49 is part of the Life Ursus project, which since the early 1990s has worked to reintroduce brown bears into the Trentino region after they were driven to extinction in northern Italy.
Professor Luigi Boitani from Rome's La Sapienza University told Italian media they now number between 50 and 60.
The mistake had been failing to use electric fences to dissuade M49 from approaching inhabited areas.
At the same time, he added, an electrified cage was never going to contain “a large, adult and spirited male bear”.
The League for the Abolition of Hunting (LAC) said it suspected the bear had been allowed to escape, so that it could be declared a danger to humans and killed.
“M49 is, of course, an escape genius… endowed with superpowers like a Marvel Comics hero,” it said.
“He just happened to climb over the fence, unharmed by electric shocks, by chance without his radio collar — and, what do you know, he can be declared public enemy number one and the escape sparks a maximum security alert”.
Michela Vittoria Brambilla, president of the Italian Defence League for Animals, told M49 to “run and save yourself!”
“We are on the side of the bear, and of freedom,” she said.