Aged 13 or 14, Goiat, as he is known, is originally from Slovenia but was taken to the northeastern region of Catalonia in 2016 to add to the number of bears in the area.
“He has an abnormal behaviour, he's too much of a predator and attacks animals that bears don't normally attack like horses, foals and mares, near homes and villages,” a spokeswoman for the Catalan regional environmental department told AFP.
“It's very strange that a bear kills adult horses — some of them weighing 500 kilos — and it's caused lots of concern,” added Guillermo Palomero, president of the Brown Bear Foundation.
The bear's predatory behaviour “could lead to his removal,” he added.
The environmental department spokeswoman confirmed, saying “the possibility of removing him from the Pyrenees' natural environment has been considered since last year”. But first authorities are trying to persuade it to end its killing spree.
“To scare it, bangers are thrown” and rubber balls and blank bullets shot, she said.
Since he came out of hibernation, Goiat is suspected of at least three attacks in the Vall d'Aran in northern Catalonia, where he was detected thanks to his GPS collar.
In April, he ate a foal, a ewe and a lamb, according to the council of the Vall d'Aran which has asked Catalan authorities for a meeting to discuss the issue.
In France, the central government's office in the Hautes-Pyrenees region on Wednesday blamed Goiat for three attacks earlier this month. In a statement, it called it an “abnormally predatory bear.”
French media says Goiat has attacked eight ewes, one ram, one pig and one mare.
Palomero however warned against calling into question the programme that has re-introduced bears into the Pyrenees. Launched in 1996, he said it “works really well”.
According to his foundation, at least 49 bears now live in the Pyrenees, on the French and Spanish sides.
Another brown bear brought over from Slovenia, Claverina, has sparked fear in Spain after having reportedly killed several ewes in the region of Navarra. Representatives of the Spanish and French governments met last week in Madrid to discuss her, with both countries agreeing to strengthen their cooperation to prevent further attacks.