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 bubble or 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.

In this lesson, students will learn about the bubblenet feeding process and how Crittercam is being used to investigate it underwater. They will read and discuss a National Geographic News article about Crittercam. They'll also consider the implications of this research for humpback conservation efforts and write letters to the director of a whale conservation organization describing how Crittercam research might help the organization in its conservation efforts.

Geography, life sciences

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"

Two to three hours

• Computer with Internet access

Students will

• view pictures of humpback whales;
• view and answer questions about a map of humpback migration routes;
• read and answer questions about a Web site discussing humpback conservation;
• read and answer questions about the bubblenet feeding process;
• illustrate what bubblenet feeding might look like underwater;
• discuss why bubblenet feeding benefits whales;
• read and answer questions about Crittercam's role in humpback conservation; and
• write letters to the director of a whale conservation organization explaining how Crittercam research might help the organization in its conservation efforts.

Have students look at pictures of humpback whales. Share these facts with the class:

• Humpbacks can grow to 17 meters (about 56 feet) long.
• They can weigh 40 tons.
• Each individual has a distinct pattern on its tail (fluke); people can recognize these patterns and identify the same whales year after year.
• Whalers used to kill large numbers of humpbacks; 150 years ago there were probably about 125,000 humpbacks, but now there are fewer than 15,000.
• Very few are killed today thanks to an international treaty.

Have students look at maps of likely humpback migration routes and discuss these questions:

• 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?

Have students go to the National Wildlife Federation's humpback whale species profile. Ask them to browse this site to find information about conservation issues concerning humpbacks, including threats the whales are facing and what can be done to help. Ask students to take notes answering these questions:

• Approximately how many humpbacks are living today? Approximately how many were there in the middle of the 19th century?
• What threats do humpbacks face today?
• What needs to be done to increase and protect the humpback population, according to this site?

Have students look at the pictures of whales bubblenet feeding at How Do Whales Feed? and read the accompanying text.

Next have students read the first half of the National Geographic News article Crittercam Reveals Secrets of the Marine World (through the paragraph beginning "And they all get together in the group...").

Discuss the different roles that whales play in bubblenet feeding.

Ask one or two student volunteers to draw a picture on the board of what bubblenet feeding might look like underwater.

Ask students why they think humpbacks feed in this manner, particularly since they are generally solitary animals. Why might the whales have specialized roles? How might this behavior benefit the whales?

Point out that in the Crittercam study they read about, DNA samples have revealed that none of the humpbacks in the feeding group were related. Why do the students think unrelated humpbacks would come together to feed? Explain that scientists aren't sure of the answers to these questions but continue to investigate them.

Explain these additional facts that scientists have learned:

• 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.

Have students read the rest of the National Geographic News article Crittercam Reveals Secrets of the Marine World (beginning with the paragraph that starts "The technology used to spy on feeding time..."). Ask students to answer these questions, either on paper or in a class discussion:

• Why is Crittercam helpful in studying bubblenet feeding?
• What information might Crittercam provide to help us "be better stewards to the ocean"?
• If you were a volunteer for an organization trying to save humpback whale populations, why might you be pleased with Crittercam's research and results?

Discuss how Crittercam can help in the conservation of humpback whales.

Have students write one- or two-paragraph letters to the director of a whale conservation organization explaining how Crittercam research might help the organization in its conservation efforts. Their letters should discuss bubblenet feeding, but they may mention other information about humpbacks that Crittercam may eventually help uncover (e.g., mating behavior).

• Have students work in groups to prepare presentations to a humpback conservation organization explaining how Crittercam research might help protect the whales. You can have the students create oral presentations, written reports, or multimedia slide shows on the computer. The presentations should address specific topics that the Crittercam scientists are studying and explain how these studies might help humpback conservation efforts.
  
  
• As an option, to illustrate the bubblenet feeding process more clearly, follow these instructions to have the class conduct a simulation of humpback bubblenet 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.

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.

How Do Whales Feed?
Humpback Whale Photographs
National Geographic News: Crittercam Reveals Secrets of the Marine World
National Geographic: Crittercam Chronicles
National Wildlife Federation: Humpback Whale Species Profile