The Pittsburgh zoo introduced four Canada lynx kittens Wednesday as they got their first check-up and round of vaccines.

The kittens – named Bjorn, Ragnar, Helga and Lagertha, after characters in the History Channel TV show “Vikings” – were born to mom Chayne on May 8. The kittens are about seven weeks old.

“They already have some personality and spunk even though they’re young little kittens,” said Dr. Ginger Sturgeon, the zoo’s director of animal health.

Native to the northern United States, Alaska and Canada, the Canada lynx is a threatened species. The four kittens will eventually move on to other zoos as part of a breeding program.

“For these Canadian lynx, they’ll live here at our facility for a year … and then move on to the next institution for breeding – and to serve as ambassadors,” Sturgeon said.

The kittens got their first round of vaccines, and Sturgeon checked to see which sex each kitten is – two boys and two girls.

They aren’t currently on display, and they’ll stay in the back room with Chayne until they’re ready to venture into the exhibit’s yard.