Manatee Anatomy Facts

  • Although they feed in an aquatic environment, manatees exclude most of the water when they swallow, which makes the contents of their stomach relatively dry. Like terrestrial herbivores (plant-eaters), manatees have large salivary glands (for lubrication and initial digestion of food).

  • Like horses, manatees are hind-gut digesters as opposed to fore-gut digesters (like cows). This means that more of the digestive processes occur further along the intestinal tract. It takes about seven days for material to pass through the manatee's digestive system.

  • A manatee's teeth are similar to the molars of some other mammals and are located in the back half of the lower and upper jaws. They are unique in that they are replaced horizontally, as opposed to vertically as in most other mammals. Tooth replacement is continuous (polyphyodont) throughout their lives, as opposed to that of other mammals that replace a single set of teeth once in a lifetime (diphyodont).

  • A manatee's circulatory system is very important in transporting heat and regulating body temperature.

  • The lungs of a manatee are unique. Unlike other mammals, their lungs are flattened and elongated and extend horizontally along the back almost to the anus. In addition, the branching pattern of the bronchi (the primary air tubes) and blood vessels in the lungs is more simple in manatees that it is in other mammals.

  • A manatee's ribs are more arched than most other mammals, allowing the lungs to be positioned much higher along the vertebral column. The manatee's elongated lung distributes the buoyant forces along more of the body, thus helping the manatee to float horizontally. This orientation also minimizes the pressure differences between different parts of the lung.

  • The manatee swims with up and down (dorsoventral) motions of its body and fluke. This motion is similar to that of cetaceans such as dolphins and whales. Fish and seals, on the other hand, swim with side to side motions.

  • The muscles of a manatee have little of the myoglobin (muscle hemoglobin) that is typical of the muscles of other diving mammals. This trait means that manatees cannot store as much oxygen as seals and dolphins, which is reflected in their relatively short (8-15 minute) and shallow (10-20 feet) dives.

  • A manatee's ribs and other long bones lack marrow cavities, which means the manatee has a dense and relatively heavy skeleton. Marrow, which produces red blood cells, is mostly restricted to the centra (bodies) of the vertebrae and possibly the sternum.

  • Manatees do not have hind limbs. Their pelvic bones are vestiges of the more complex structures of their ancestors. The pelvic vestiges are attachment sites for muscles.

  • Manatees live in both fresh and salt water. Their kidneys filter blood to control levels of salt and to maintain water balance. Their urine is stored in the bladder until it is released into the environment.

  • A female manatee's mammary glands (milk glands) and teats are located behind the forelimbs or flippers, one per side. Like cattle and goats, a manatee's milk glands have no storage sacs, so manatee calves suckle frequently at short intervals.

  • Compared to other mammals of the same size, manatees have relatively small brains. Their brains are very smooth and have few surface folds that are associated with higher intelligence in other mammals.

Manatee Anatomy Facts courtesy of the Florida Fish and Wildlife Conservation Commission, Bureau of Protected Species

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