Manatee Gestation Period: How Long Is a Manatee Pregnant?

How long is a manatee pregnant?

A manatee carries her calf for an average of 380 days, or about 12 months and 2 weeks. Counting from the breeding date, calving is normal anywhere from day 365 to day 400.

Key checkpoints across the 380-day manatee gestation, measured in days from breeding:

Estimate your manatee's calving date

Enter the breeding date for an estimated calving date at 380 days.

Manatee gestation stages, month by month

Signs a manatee is pregnant

• A mating herd seen around the female about a year earlier
• No visible change for most of the pregnancy
• Ultrasound or hormone tests in managed care
• A wider body and increased feeding in late gestation

Signs of approaching calving

• The female moving to calm, protected water
• Restlessness and staying apart from other manatees 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 manatee gestation length

• A West Indian manatee, which includes the Florida manatee, is pregnant for roughly 12 to 14 months.
• Manatees usually have a single calf, roughly 1 to 1.4 metres long and around 30 kg at birth. Twins occur but are rare.
• When a female is ready to mate, she may be followed by a 'mating herd' of a dozen or more males for days or even weeks.
• Calves are born underwater and can swim to the surface to breathe within minutes, often with help from their mother.
• Calves nurse from teats located just behind the mother's flippers, usually for one to two years, and stay with her for up to two years.
• Females typically give birth only every two to five years, so the population grows slowly, which is why manatees are vulnerable to boat strikes and cold stress.

Manatee gestation chart

Every fifth breeding date across the year with the matching calving date, calculated at 380 days. Find the row closest to the date the manatee was served; because normal gestation spans 365 to 400 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 manatee gestation figures

Figures on this page are drawn from Florida Fish and Wildlife Conservation Commission and U.S. Fish and Wildlife Service manatee information, and published manatee reproduction research, and checked against the references below. Averages describe healthy animals under normal management; individual animals vary, and nothing here replaces advice from your vet.

• Florida Fish and Wildlife Conservation Commission — Florida manatee biology
• U.S. Fish and Wildlife Service — West Indian manatee information
• 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