A manatee can move each side of its lip pads independently. This
flexibility allows the manatee to "grab" aquatic plants and draw
them into its mouth.
Manatees do not have eyelashes, their eyes close in a circular motion, much like an aperture on a
camera. They have a lid-like membrane (called a nictitating
membrane) that closes over their eyes for protection when they
are under water.
Manatees can hear very well despite the absence
of external ear lobes.
A manatee's heart beats at a rate of 50
to 60 beats a minute. The heart rate slows down to 30 beats a
minute during a long dive.
Manatees have no "biting" teeth, only
"grinding" teeth. A manatee's teeth (all molars) are constantly
being replaced. New teeth come in at the back of the jaw and
move forward about a centimeter a month. The front molars
eventually fall out and are replaced by the teeth behind them.
This tooth replacement is an adaptation to the manatee's diet,
as it consumes plants that may hold a lot of sand.
only six cervical (neck) vertebrae. Most all other mammals,
including giraffes, have seven. As a result, manatees cannot
turn their heads sideways; they must turn their whole body
around to look behind them.
The manatee's rib bones are solid,
there is no marrow. They make red blood cells in their sternum
where marrow is found.
The manatee has pelvic bones, but they
are not attached to its skeletal frame, they are remnants of the
time manatees lived on land.
The bones are found in a cartilage
tissue area of the body in the vicinity of the reproductive
organs and the urinary bladder. The bones are soft when the
manatee is young and later harden as they mature. Other remnant
bones found in the manatee are the hyoid bones located near the
neck region. These bones are similar to the Adam's apple in
humans. Today, there is no known use of these bones in the
The manatee's lungs lie along its backbone instead of
along its rib cage as is found in most mammals. The lungs are
long (1 meter or more in adults), wide (20 cm), and thin (5 cm
or less). Besides breathing, the lungs help the manatee with
The bones in a manatee's flipper are similar
to a human hand. The jointed "finger bones" of the flipper help
the manatee move through the water, bring food to its mouth, and
Three or four nails are found at the end of each
The adult manatee averages about 10 feet long and
weighs about 1000 pounds.