Hippopotamus Gestation Period: How Long Is a Hippopotamus Pregnant?

How long is a hippopotamus pregnant?

A hippopotamus carries her calf for an average of 240 days, or about 7 months and 3 weeks. Counting from the breeding date, calving is normal anywhere from day 225 to day 250.

Key checkpoints across the 240-day hippopotamus gestation, measured in days from breeding:

Estimate your hippopotamus' calving date

Enter the breeding date for an estimated calving date at 240 days.

Hippopotamus gestation stages, month by month

Signs a hippopotamus is pregnant

• No outward change for the first months of pregnancy
• Hormone monitoring or ultrasound confirms pregnancy in zoos
• A fuller, rounder belly in the last two to three months
• Increased aggression towards other hippos as calving approaches

Signs of approaching calving

• Udder development in the final weeks
• The cow leaving the group and seeking shallow water or dense reeds
• Contact your vet if labour stalls, if the animal strains without progress, or if there is abnormal discharge before calving begins.

What affects hippopotamus gestation length

• A hippo is pregnant for about 240 days, close to eight months, which is short for an animal weighing well over a tonne.
• Hippos mate in the water, and calves are often born in shallow water too, although some cows give birth on land in dense cover.
• In many populations conception peaks in the dry season, so most calves arrive during the rains, when grazing is best for the nursing mother.
• A newborn calf typically weighs somewhere around 25 to 50 kg and can nurse underwater, closing its ears and nostrils while it feeds.
• The cow leaves the group to give birth and keeps the calf apart for the first days before rejoining, partly to protect it from aggressive adults.
• Females usually calve about once every two years, so a cow raises one calf at a time.

Hippopotamus gestation chart

Every fifth breeding date across the year with the matching calving date, calculated at 240 days. Find the row closest to the date the hippopotamus was served; because normal gestation spans 225 to 250 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 hippopotamus gestation figures

Figures on this page are drawn from zoo hippopotamus husbandry guidance, published field studies of wild hippo populations and natural history references, 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