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Grades 3-5
Overview:
The humpback whale is an endangered species that inhabits both the Atlantic and Pacific Oceans. Humpbacks in both oceans have long migration routes. For example, North Pacific humpbacks mate and give birth in Hawaii and Baja California in the winter and migrate to Alaska to feed each summer. They practice an unusual group feeding behavior called bubblenet feeding (also known as lunge feeding), in which a group of whales works together to capture large schools of herring.

Each whale has its own role in the process: one blows bubbles around the herring school to keep the fish from escaping, others vocalize to scare or confuse the fish and help bring them to the surface, and others herd the fish together and upwards. Once the fish are at the surface, all the whales lunge upwards with their huge mouths wide open and try to gulp as many herring as they can.

Students will learn about this process and conduct their own simulation of bubblenet feeding to see how it might look underwater. They will discuss why humpbacks might feed in this manner, and they'll draw pictures showing what bubblenet feeding might look like from the Crittercam's viewpoint.

Connections to the Curriculum:
Geography, life sciences
Connections to the National Geography Standards:
Standard 8: "The characteristics and spatial distribution of ecosystems on Earth's surface"
Standard 18: "How to apply geography to interpret the present and plan for the future"
Time:
One to two hours

Materials Required:
  • Computer with Internet access
  • Construction paper and other materials for making hats or costumes (optional)
  • Blowing bubbles (optional)
Objectives:
Students will
  • view and answer questions about a map of humpback migration routes;
  • discuss the pros and cons of animals feeding alone versus in groups;
  • see pictures of humpback whales feeding using the bubblenet method;
  • do a simulation of bubblenet feeding;
  • discuss the purposes and advantages of bubblenet feeding; and
  • draw pictures showing what bubblenet feeding might look like from Crittercam's viewpoint, and write captions describing the pictures.
Geographic Skills:

Acquiring Geographic Information
Organizing Geographic Information
Answering Geographic Questions
Analyzing Geographic Information

S u g g e s t e d   P r o c e d u r e
Opening:
Have students look at these pictures of humpback whales . Share these facts with the class:
  • Humpbacks can grow to 56 feet (17 meters) long.
  • They can weigh about 40 tons.
  • Each individual has a distinct pattern on its tail (fluke) and people can recognize these patterns and identify the same whales year after year.
  • Whalers used to kill large numbers of humpbacks. Over a century ago there were probably about 125,000 humpbacks but now there are fewer than 15,000. Today, very few are killed, thanks to an international treaty that protects them.
Have students read more about humpback whales (have them scroll down to the "Habitat and Range" and "Migration" sections, in particular). Ask them to answer these questions, based on what they see at the map:
  • Where do the humpbacks eat?
  • Where do they give birth to their calves?
  • At what times of year do you think they feed and have babies?
Discuss students' answers to the above questions as a class. Make sure they understand that humpbacks feed in northern waters in the summer and have their calves in warm waters in the winter.
Development:
Have students look at a photograph of baleen . Explain that humpbacks are baleen whales, which means they don't have teeth. They use their baleen to filter tiny plankton and shrimplike krill out of the water. In their northern feeding grounds, however, humpbacks often eat small fish, particularly herring , which swim in large schools.

Ask students to think about the eating behaviors of animals they're familiar with. Which animals eat alone? Which animals eat in groups? What are some pros and cons of eating alone versus eating in groups? What might be some pros and cons of eating alone versus in groups for humpback whales?

Explain that humpbacks are generally solitary animals and spend a good deal of time by themselves. When they eat in northern waters such as Alaska, however, they often work in groups to capture fish for their meals.

Have students go to How Do Whales Feed? and scroll down to the section entitled "Bubble Feeding." Ask students to take turns reading these sentences out loud as everyone looks at the pictures.

Tell the class that each whale has a special role to play in the bubblenet feeding process. For example, one whale is responsible for blowing the bubbles to trap the fish, which will not travel through the net of bubbles. Several other whales make sounds that scare or confuse the fish and draw them up to the surface. Other whales swim in circles and "herd" the fish up toward the surface, where all the whales rise with open mouths and try to capture as many fish as possible.

Explain these additional facts that scientists have discovered:

  • Not all whales get a lot of herring, but scientists aren't sure why some get more than others.
  • The whales don't always cooperate perfectly; sometimes they'll butt each other and jockey for position underwater.
If your computers have speakers, have students listen to some humpback songs. They should go to National Geographic's Radio Expeditions: Humpback Whales and select "Symphony of the Deep" on the lower right. They should scroll down and click "Listen" in the yellow text. This will open a RealAudio file that will play some narration and then the whale songs. It would be ideal to listen to this as a class so that students hear only one audio file rather than a cacophony of whale sounds from different computers.

Next, follow these instructions to conduct a simulation of humpback bubble feeding:

  • Assign one student to be the "bubble blower," about five students to be "herders," and three to be "singers." The rest of the class will be herring (make sure most students are herring so there are plenty of fish for the whales to capture). The whales and fish should have special hats, fins, or other props for identification. Depending on your time frame, students could make and wear construction paper hats of one of two colors, depending on their roles, or they could use craft materials to make costumes that look like the species they're playing.
  • Have the herring stand together in their "school."
  • Tell the bubble blower to blow bubbles in a circle around the room.
  • Instruct the singers to make "incredibly beautiful and haunting sounds" (as described here ) to scare the herring, and ask the herders to encircle the herring and get them to move closer to the center.
  • Tell the herring that, since they're afraid of or confused by the bubbles, they can't move through them. The songs and the presence of the huge whales herding them are also frightening and confusing, so they need to move to the center of the room.
  • Once the herring have been successfully herded, all the whales should open their huge mouths and "eat" the herring.

Closing:
Discuss the bubblenet feeding technique as a class. Ask students why they think the whales eat in this manner. Why do they tend to feed in groups rather than alone? Why do the whales have special roles (bubble blower, herder, singer)?
Suggested Student Assessment:
If students haven't learned about Crittercam yet, have them go to the Crittercam Chronicles and read the introductory page and the page about whales.

Ask students to draw pictures from a whale's point of view, showing what Crittercam might see as it is attached to the back of a feeding humpback whale.

Ask the students to write captions to accompany their pictures, explaining what's going on in the pictures and what each whale is doing.

Extending the Lesson:
  • Explain that humpback whales are an endangered species and that many scientists and conservation organizations are working to study them and educate people about how to save these animals. Have students brainstorm how Crittercam might assist in efforts to protect the humpback, and have them write and illustrate paragraphs explaining their ideas for linking Crittercam with conservation efforts.

  • Have younger students color the humpback whales in the National Geographic Coloring Book .

This material is based on work supported by the National Science Foundation under Grant No. 0229817.

Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

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