CINCINNATI — The Cincinnati Zoo is on 24-hour watch as its mom hippo, Bibi, shows signs she could give birth at any minute. 

The zoo posted a photo of Bibi on its Instagram, saying, "it could be any day now!"

The zoo and its caretakers are hosting a Facebook live that began at noon Wednesday to talk about the pregnancy.

Bibi is the mother of beloved hippo, Fiona, meaning she will become a big sister. The zoo announced Bibi's pregnancy in April and expected the baby to be born around mid-August, but zoo officials said the hippo could be born 30 days before or after the due date.

On Tuesday, the zoo reported that Bibi was showing signs of restlessness — another signal she could soon be in labor.

"The hippo team is optimistic that the baby will be born within the normal birth window," the zoo posted on Instagram in July, adding that her fetus is bigger than the size of Fiona when she was born. 

The zoo said its reproductive physiologists at the Center for Conservation and Research of Endangered Wildlife are assisting Bibi's caretakers to ensure the pregnancy goes as smooth as possible for the mother. 

The father of the soon-to-be born hippo is Tucker, who arrived in Cincinnati in September 2021 from the San Francisco Zoo after the Association of Zoos and Aquariums (AZA) Species Survival Plan (SSP) Program recommended the transfer for breeding purposes. 

Zookeepers will probably separate the father, Tucker, from Bibi during the birth and for about two weeks after. In the wild, female hippos leave the group a few days before birth and return with the calf 10-14 days later, according to the zoo.

Digital reporter Casey Weldon contributed to this report.