Dolphin Gestation Period: How Long Is a Dolphin Pregnant?

How long is a dolphin pregnant?

A dolphin carries her calf for an average of 365 days, or about 11 months and 4 weeks. Counting from the breeding date, calving is normal anywhere from day 340 to day 380.

Key checkpoints across the 365-day dolphin gestation, measured in days from breeding:

Estimate your dolphin's calving date

Enter the breeding date for an estimated calving date at 365 days.

Dolphin gestation stages, month by month

Signs a dolphin is pregnant

• No visible change for the first several months
• Ultrasound confirms pregnancy in managed care
• A gradually widening abdomen from mid gestation
• Increased appetite as the calf grows

Signs of approaching calving

• Visible fetal movement and a swollen genital area in the final weeks
• Swimming slowly, arching the body and staying near other females shortly before birth
• Contact your vet if labour stalls, if the animal strains without progress, or if there is abnormal discharge before calving begins.

What affects dolphin gestation length

• This page uses the common bottlenose dolphin, the species most people mean by 'dolphin'. Its gestation is about 12 months.
• Bottlenose dolphins can breed all year, but many populations show seasonal calving peaks, often in the warmer months.
• Calves are usually born tail first, which helps keep the calf from drowning before it is fully out.
• Newborn bottlenose calves are roughly 1 to 1.3 metres long. The mother, often with help from another female, guides the calf to the surface for its first breath.
• Calves nurse for a year or more, often well over a year, and typically stay with their mother for several years while they learn to hunt.
• With a year-long pregnancy and a long period of care, females usually have a calf only every few years.

Dolphin gestation chart

Every fifth breeding date across the year with the matching calving date, calculated at 365 days. Find the row closest to the date the dolphin was served; because normal gestation spans 340 to 380 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 dolphin gestation figures

Figures on this page are drawn from NOAA Fisheries species information, aquarium reproduction programmes and long-term studies of wild bottlenose dolphin 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.

• NOAA Fisheries — common bottlenose dolphin species profile
• 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