MEMPHIS (AP) — Two African penguins have been born at the zoo in Memphis, Tennessee, bringing the total number of the birds housed there to 20.

The penguin chicks were born at the end of October but they are not yet on exhibit because they are currently being hand-raised, Memphis Zoo officials said in a news release.

The African black-footed penguin can be found in large colonies in southern Africa. They are one of 17 species of penguins found in the world and are considered the most endangered type of penguins, the zoo said.

Forty-two penguin chicks have been hatched and reared at the Memphis zoo, officials said. There are currently 20 penguin chicks housed at the zoo.