A man who broke into the Calgary Zoo overnight and scaled a fence around a tiger exhibit is hospitalized with serious injuries to his arms after he was attacked by a tiger.

Zoo spokesman Grahame Newton says two men, both 27, broke into the zoo at around 1 a.m. early Monday by scaling an 8-feet-high main fence topped with barbed wire.

Newton says one man climbed an outer safety fence around the tiger enclosure. A Siberian tiger, a 2-year-old male named Vitali, hooked the man with a claw and pulled the man's arm through the inner fence.

Police are investigating and say they are considering charges of breaking and entering. They haven't determined whether alcohol was involved.