In earlier surveys that percentage had been much higher. It was concluded that percentage of birthrates had diminished rapidly. It is not known if the birth rate percentage is high enough to replace the 120 manatees that are killed every year by human influences in Florida. The majority of female manatees breed when they are seven to nine years old. Some may reproduce earlier, but such births are unsuccessful because the mothers lack of experience in birthing and survival.
Mothers usually wait another three to five years before having another calf.
Although a female who has lost a calf may reproduce sooner. Calving occurs throughout the year because of migration to warmer climates. Calves remain dependent on their mothers for up to two years. They nurse from teats located at the junction of the forelimbs of the body. Manatee milk contains more fat than cows milk does.