How Marine Mammals Hold Their Breath Underwater

August 5, 2013

Unlocking Word Meanings

Read the following words/expressions found in today’s article. 

1. mammal [MAM-uh l] (n.) – a warm-blooded animal that has hair or fur on the skin and can produce milk for its young
Example: Marine mammals can produce milk for their babies.

2. repel [ri-PEL] (v.) – to keep away or to cause to move away
Example: Disturbances from humans repel the dolphins in the sea.

3. evolve [ih-VOLV] (v.) – to gradually develop
Example: Some experts think that humans have evolved from the apes.

4. anatomical [an-uh-TOM-i-kuh l] (adj.) – relating to the study of bodily structure or anatomy
Example: Each mammal has different anatomical structure.

5. transfusion [trans-FYOO-zhuh n] (n.) – a process of transferring blood or other fluid into the blood vessel of a person or animal
Example: The patient needs to have blood transfusion after losing so much blood.


Read the text below.
Scientists have discovered the secret to how marine mammals manage to hold their breath for a long time underwater.

The mystery on how mammals can store oxygen in their bodies has long been puzzling the scientists.  The research, which was published on the Science journal, involved a team of researchers who focused on the myoglobin [mahy-uh-gloh-bin] in mammals. Myoglobin is a kind of protein that allows our muscles to store oxygen.

In this study, the research team used muscle samples from three kinds of mammals: land-based, semi-aquatic, and marine mammals.

The researchers specifically studied the electrical charge on the surface of myoglobin. They found that the presence of the protein is greater in marine mammals than land-based mammals.  

Scott Mirceta, the lead researcher, said that the myoglobin molecules have a strong positive charge, which makes the molecules repel each other. Thus, the proteins are prevented from sticking together, allowing a much higher concentration of myoglobin. With higher myoglobin concentration, marine mammals can store more oxygen in their muscles.

This discovery helps scientists understand how mammals have evolved over the years. The results also allow experts to know the anatomical changes that occurred during the land-to-water transitions among mammals.

With the newly discovered data, scientists could determine how many times the marine mammals can dive. The study can also help experts better understand the evolution of deep diving.

In addition, the study may be able to benefit the medical industry. Experts can use the study’s discoveries to develop oxygen-carrying liquids that can deliver oxygen to tissues when blood transfusion can no longer be done.

Viewpoint Discussion

Enjoy a discussion with your tutor.  

Discussion A

·         Do you think the study on how marine mammals breathe underwater is important? Please explain your answer.
·         In your opinion, how can studying the evolution of marine mammals benefit the humans?

Discussion B

·         What are the disadvantages of using animals in research or experiments? Please explain your answer.
·         Do you think scientists should continue conducting research that involves animals? Why or why not?


August 5, 2013