Sonar and Marine Mammals

Name: _________________________________       Date: _____________

Sonar is a tool that uses high energy sound waves to find underwater objects. Its use is growing in oceans around the globe, by both research and military ships. Evidence is growing that underwater sonar tests are causing big problems for whales and dolphins. Marine mammals can be harmed physically or confused by the tests. Sonar has also been linked to strandings.

In this activity, you'll learn more about how sonar affects marine mammals. You'll also learn about recent efforts to protect whales and dolphins from these tests. To begin, go to the United State's Navy's Understanding Sonar page. Read the first paragraph.

1. What do the letters in the word "sonar" stand for?
   
   
   
2. What is sonar used for by the Navy?
   
   
   
3. Read the paragraph Passive Sonar. Describe how passive sonar works.
   
   
   
   
4. Continue to the paragraph Active Sonar. How is active sonar different from passive sonar?
   
   
   
   
5. Read about Marine Mammals and Sound. Describe how and why marine mammals use echolocation.
   
   
   
   
6. Scroll to the last paragraph. If the Navy is concerned about the effects of active sonar on marine mammals, why does it keep using it?
   
   
   
   
7. Now go to the Whales and Sonar Strandings page. What is the definition of a stranding?
   
   
   
   
   
8. What causes are listed for strandings?
   
   
   
   
9. Describe what happened in the Bahamas in 2000.
   
   
   
   
10. What did the Navy and NOAA learn from the Bahama stranding?
    
    
    
    
11. Read NOAA's Mass Stranding of Melon-Headed Whales report. Describe what happened in July 2004.
    
    
    
    
12. What is the most likely hypothesis for why the whales became stranded?
    
    
    
    
13. Read Protecting Whales from Dangerous Sonar then watch the video. What is the NRDC doing to protect marine mammals from sonar?
    
    
    
    
14. Scroll to Active Sonar: How It Harms Marine Life. Describe the different ways sonar physically harms marine mammals.
    
    
    
    
15. Click the Act Now link at the bottom of the page. How can you help protect marine mammals from sonar?