Adelaide Zoo orangutan loses sixth baby

Adelaide Zoo's critically endangered Sumatran orangutan, Karta, has lost her sixth baby.

Zoos SA veterinarian Ian Smith says the exact cause of death is unknown but there are indications the infant was stillborn.

Karta had another stillborn in January last year, while four other babies have died soon after birth since 1995.

Dr Smith said on Thursday Karta and her mate Kluet were in good health but would be given appropriate time and space to mourn.