Manatee Manatee
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Manatee Adaptations: The Lungs

Lung Size, Shape and Location
Manatees have unique lungs. Unlike other mammals, manatee lungs are flattened-out and long. They are positioned lengthwise along the back.

Can you find the lungs?
(Click on diagram to enlarge)


The real deal: Long lungs


Amount of Air Exchange/Capacity
The manatee's amount of air exchange/capacity is massive. How do humans compare? How do scientists measure lung volume? Manatees Hugh and Buffet at Mote Marine Laboratory have actually been trained to exhale into a device called a "spirometer". Watch the video below--who do you think has the most lung power?

Lung Power!
Who's Got the Most--Human or Manatee?

(Viewing Tips)


Credit: Mote Marine Laboratory

The manatee's amount of air exchange is higher than any other mammal's. Humans are thought to exchange only about 10% in a breath.

In contrast, the rate of exchange of air in the manatee's lungs is very quick and very complete. In a single breath, manatees can exchange about 90% of the air that is in their lungs. This is even more amazing because manatees only breathe through their nostrils. They don't breathe through their mouth.

Photo Credit: FWC

"One breath is all I need"
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To achieve such a large air exchange, manatees will blow out or exhale very forcefully when they reach the water surface, and then breathe in or inhale. Manatees have muscles in the bronchials and a very muscular diaphragm, which helps to facilitate rapid air exchange.

Because of this large air exchange, manatees take in more oxygen with each breath. That allows them to stay underwater longer between breaths. While resting, a manatees can stay underwater for as long as 20 minutes before coming up for another breath.

The lengthy manatee lungs also help them to rise and fall in the water, and spread out the bouyancy very effectively along the length of the body helping them to float

"That Thing Got A Hemi?"
Another unique anatomical feature of manatees is that instead of having a diaphragm that divides the animal in half across the chest , they have a hemi-diaphragm, like two diaphragms, that runs the length of much of their torso. And each of these lungs can exchange air separately. This is a huge benefit, and just works in their favor for any animal that has been hit by a boat and had one of the lungs injured. Though one lung is no longer functional, the animal is still able to survive using the other lung. There are some animals in the wild that scientists have seen with this injury, and you can see the manatee sort of lists to one side, they're a little crooked in the water. But such a manatee is still using the uninjured lung and they're able to get by with just that one lung exchanging.

Try This! Investigations/Journaling

1. How Much Air Do You Exchange In One Breath?
After a normal breath, exhale. Then without inhaling again, blow out. It's quite amazing how much more air can be expelled from one's lungs with the extra effort! This short demonstration helps you realize how little air humans exchange during normal breathing. When you blew out after exhaling, there was still a lot more air in your lungs to exchange.

2. Comparing Your Lungs
How are your lungs situated in your body? What shape are they? How does the size of your lungs compare to the size of a manatees? Compare these and other aspects of your lungs to manatee lungs, and summarize the similarities and differences in your journal.

3. What makes it possible for animals as large as manatees to easily float and move in water? Write your ideas, then try these investigations into density and the properties of salt water. summarize your new understandings in your journal.

4. Underwater mammals differ in many ways from mammals that live on land. In what ways are land mammals and underwater mammals similar? What common characteristics qualify both groups of animals to be called mammals?

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