About the Circulatory System of a Manatee

Manatees are part of the small group of mammals that spend their entire lives in water, only surfacing to breathe. One of the reasons that manatees can only live in the water is because their weight needs the buoyancy of water. On land, their body weight would likely crush their internal organs.

Identification

Manatees can grow as long as 15 feet and weight up to 2000 lbs. They There are three types of manatees: West Indian, Amazonian and African. All three are currently endangered, and it is illegal to hunt manatees in the United States of America. The reasons for their endangerment include hunting and injuries from motor boats.

The Facts

The circulatory system of a manatee is similar to other mammals. A manatee heart has four chambers and beats about 60 times every minute (a human heart beats around 80 times a minute). During long dives, a manatee's heartbeat can slow to as little as 30 beats per minute.

Significance

It is vital that manatees remain in warmer waters. Even though they weight a lot, manatees do not have blubber like whales. In fact, it is difficult for manatees to maintain their body temperature and to stay warm because of their size and lack of fat. Because their heart rate and metabolism are slow, manatees simply don't generate much body heat. Many breeds of manatees live in warm, tropical waters, but Florida manatees live in waters that can drop in temperature. Even a drop to 70 degrees Fahrenheit can be dangerous for these water-dependent mammals and can cause illness. If this species is to be preserved for future generations, more protections must be put in place and more awareness focused on conservation of manatees.

Expert Insight

In the winter, you'll often find Florida's manatees snuggled up where the warmer natural springs and rivers come into the coastal waters. They also can be found in Tampa near Teco Tampa Electric, where the warm waters the company releases back into the bay attract hundreds of manatees in the winter. The company has build a manatee-viewing station and museum to educate the public on this endangered animal and to allow both tourists and local residents to observe manatees in a natural environment. You can book reservations or find out when public viewing starts at http://www.tampaelectric.com/manatee/.

Misconceptions

Manatees are often thought to be related to the walrus. Actually, they are more closely linked to elephants.

Resources

• National Geographic information on manatees