Monarto Zoo giraffe calves named Bwanji, Mtoto on World Giraffe Day | VIDEO

Video: Zoos SA.

Two of Monarto Zoo's youngest residents have been given names to celebrate World Giraffe Day.

The giraffe calves will be known as Bwanji, meaning "hello" in Zambian, and Mtoto, meaning "child" in Swahili.

Keeper Matt Brewer said the youngsters were doing really well as part of the zoo's herd.

As the 46th and 47th calves born at Monarto, they are also an indication of the success of its breeding program, which aims to counterbalance the effect habitat loss, poaching and war have had on the species in its native African environment.

About 70,000 giraffes are left in the wild, down from about 155,000 in 1985.

"Giraffes are a very iconic and well-loved species, but sadly they are facing a bit of trouble in the wild," Mr Brewer said.

"Our herd, including the newest calves, are playing an important role as ambassadors for the species."

The Giraffe Conservation Foundation annually encourages zoos and other organisations around the world to celebrate the world's longest-necked animal on what is, in the northern hemisphere, the longest day of the year: June 21.