BERLIN (AP) — Naming two baby giraffes proved to be a major challenge for a Berlin zoo this summer.

After the half-siblings were born on June 24 and August 11 at the Tierpark, one of the city’s two zoos, officials turned to a school class and the zoo director’s 18-year-old daughter for inspiration.

The class shared the name of their mascot, a giraffe named Gisbert, which was shortened to “Berti” after the new bull. And the zoo director’s teenage daughter, Emily, is about 1.80 meters (5.91 feet) tall – about the size of a newborn baby giraffe – so the female cub now bears the same name.

The children are Rothschild giraffes, which are threatened with extinction, and they live in the herd with nine other animals – including their mothers and their father. And a tenth is on the way: Maude, the giraffe cow, is pregnant and is due to give birth in September.

Berti and Emily’s names were officially announced on Thursday as two of the cows, 21-year-old Paula and 17-year-old Andrea, groomed themselves for the cameras with their long, blue tongues. The newborns remained in the background of the habitat, feeding from their mothers’ udders and frolicking on the grass.

Rothschild giraffes are classified as “vulnerable” by the International Union for Conservation of Nature, with fewer than 1,100 remaining in the wild. Their territories in Kenya and Uganda are threatened due to illegal hunting and habitat destruction caused by the expansion of agriculture.

Berti could grow to 5.80 meters tall and weigh 1.8 tons, while Emily could grow to 4.50 meters tall and weigh 1.2 tons. In care, they can live up to 35 years – 10 years longer than in the wild.

Claudia Walther, the giraffe keeper, said that calves are usually born at the zoo every two years. This year is “really special” because the number of pregnancies has increased.

“Three calves in a row and so close together, that’s really great,” she said.