ST. LOUIS — Kallu and Kallik, the twin polar bears who replaced 12-year-old Kali, have made their debut at the Saint Louis Zoo.

The Zoo says the two love to play and spar during the day and sleep side-by-side at night. Kallik, the older, yet smaller of the two, weighs 620 pounds and is very curious. His younger brother, Kallu, weighs 740 pounds and is more cautious than his brother.

Before coming to St. Louis, the twins lived in the Toledo Zoo. But now, they live in Polar Bear Point, which has two temperature-controlled pools and an arctic cave room.

Kali has been sent to the Toledo Zoo to be paired with the twins' mother, 26-year-old Crystal. The exchange was made to enhance the genetic diversity of the species.