How Fast Do Manatees Grow?
Manatee mother and calf by David R. Schrichte
(Photo © David R. Schrichte)

Q. About how fast do manatees grow, and at what age do they stop?
--Alison Elgass, Illinois

A. Just like humans, manatees can vary in how quickly they grow and when they stop. At birth, manatees are usually approximately four feet long and weigh around 60 pounds. For the first one to two years of its life, a manatee is considered a calf and is less than eight feet long. At the age of three years, manatees usually fall into the category of “subadult” and range between about seven and a half and nine feet in length. Manatees are typically considered adults by the time they are five years of age, or approximately nine feet long, or larger. So, if a manatee is four feet long at birth and nine feet long at the age of five, that manatee may have grown one foot each year. Once a manatee reaches adulthood though, growth slows. Manatees can grow to be 13 feet long and weigh upwards of 3,000 pounds, although many adults average 10 feet in length and weigh in at approximately 1,000 pounds. Females tend to be slightly larger than males, and they certainly weigh more during pregnancy.

--Katie Tripp, Ph.D.
Director of Science and Conservation, Save the Manatee Club

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