A lioness and eight tigers belonging to a private Russian circus died in the back of a truck during a 20-hour trip through Siberia, authorities said Tuesday.
The animals were on their way to the eastern Siberian city of Yatkutsk to perform in New Year shows. When the "Dream" circus's trucks were unloaded shortly after midnight Tuesday, the tigers and lioness were found dead, local authorities said in a statement.
The region's Interior Ministry said that an investigation has been opened and early indications point to "poisoning."
"Preliminary data indicates that the animals could have died from inhaling exhaust fumes," a local police spokesman told the state-run RIA Novosti press agency.
The felines were traveling in a refrigerator container, which, according to an employee of the circus where the tigers and lioness were to perform, caused their death.
"The exotic animals were kept in a container without air-conditioning or heating," the employee told RIA Novisti. "The lioness and tigers had inhaled exhaust fumes and froze to death."
Pictures have emerged on Russian Web sites of the dead tigers lying on top of each other. The chest of one was cut open; the site kursor.ru says authorities did this to perform tests.
The animals' journey started in Khabarovsk, near Russia's Pacific coast. From there they traveled to the city of Neryungri where they were fed, according to their owners. Then they started the 500-mile trek through Siberia to Yatkutsk, during which time they died.
"Those who were in charge of transportation are guilty and have to be held responsible," says Natalia Dronova from the World Wildlife Foundation in Moscow.
The "Dream" circus is subject to fewer regulations than those that are part of Russia's famous state circus organization.