Chimpanzee Gestation Period: How Long Is a Chimpanzee Pregnant?

How long is a chimpanzee pregnant?

A chimpanzee carries her infant for an average of 237 days, or about 7 months and 3 weeks. Counting from the breeding date, birthing is normal anywhere from day 230 to day 240.

Key checkpoints across the 237-day chimpanzee gestation, measured in days from breeding:

Estimate your chimpanzee's birthing date

Enter the breeding date for an estimated birthing date at 237 days.

Chimpanzee gestation stages, month by month

Signs a chimpanzee is pregnant

• The monthly sexual swelling no longer appears
• A positive urine pregnancy test, as used in zoos
• A gradually rounded belly from around month four
• Enlarged breasts and nipples in the second half of pregnancy

Signs of approaching birthing

• Slowing down and resting more in the final weeks
• Building nests more often and staying apart from the group just before birth
• Contact your vet if labour stalls, if the animal strains without progress, or if there is abnormal discharge before birthing begins.

What affects chimpanzee gestation length

• A chimpanzee is pregnant for about 230 to 240 days, roughly eight months, a little shorter than a human pregnancy.
• Female chimps show a large pink swelling of the genital skin around the fertile part of their cycle. When a female becomes pregnant, the swelling stops returning.
• Pregnancy can be confirmed with human pregnancy tests, because chimps produce a very similar pregnancy hormone. Zoos use this routinely.
• Chimps usually have one infant, weighing about 1.5 to 2 kg. Twins happen but are uncommon.
• Infants cling to their mother's belly for the first months, then ride on her back. They nurse for around four to five years.
• Because of this long period of care, wild females usually give birth only every five years or so.

Chimpanzee gestation chart

Every fifth breeding date across the year with the matching birthing date, calculated at 237 days. Find the row closest to the date the chimpanzee was served; because normal gestation spans 230 to 240 days, plan for a window of a few days either side. Filter by month, or print the chart for the barn wall or breeding record: navigation, buttons and adverts are hidden on paper.

Sources for chimpanzee gestation figures

Figures on this page are drawn from AZA great ape husbandry guidance, zoo primate reproduction records and long-term field studies of wild chimpanzee communities, and checked against the references below. Averages describe healthy animals under normal management; individual animals vary, and nothing here replaces advice from your vet.

• Association of Zoos and Aquariums (AZA) — species husbandry and animal care manuals
• Smithsonian's National Zoo & Conservation Biology Institute — species fact sheets
• Published zoological studies of captive births