Polish authorities are searching for a man who tangled with a bear at Warsaw's zoo and escaped, leaving traces of his blood behind.

Maria Krakowiak, head of the animals of prey section at the Warsaw zoo, said Thursday the man hasn't been found after his dangerous stunt Sunday.

Some blood was found Sunday outside the enclosure but it appears the man was not badly hurt and no local hospitals reported treating him. Krakowiak said the stunt was "very dangerous" and "could have ended much worse."

A witness to the stunt posted photos on the Internet showing the man in shorts and with bare feet. From the photos it appears the bear tried to bite the man's arm and that the man hit the bear.