Viktor Rassadin said Pers the poodle ran away from his trainer with the St. Petersburg-based circus before a performance this week in the city of Cheboksary, RIA Novosti reported Friday.
"He must have sensed a female dog nearby and got to chasing it. He's male, after all," Rassadin said.
Rassadin said the circus will seek a replacement for Pers if he is not found by next week.
Exploding whale video goes viral on Internet
Jordana Brewster on Paul Walker: 'He was an enormous presence in my life'