Orca United Nations
Understanding Behavioral Adaptations: Orca Society
Students study the vocalizations, hunting techniques and social behaviors of four communities of orcas and discuss whether, due to their differences, they can be considered different cultures.
Two or three class periods
Students will be able to:
- Recognize similarities and differences between sets of data.
- Analyze data based on set criteria.
- Explain how organisms are uniquely adapted to their environment.
acoustic data — recorded sounds and sound pictures (spectrograms)
behavioral adaptation — any action or response that increases an organism's chances for survival
clan — related orca pods using the same or similar calls
culture — the set of learned behaviors and social traditions specific to a population that are unique, consistent and passed on from generation to generation
echolocation — the use of echoes from sound waves to create a sensory map
hydrophone — an underwater microphone used to record vocalizations and other sounds
matriarch — the oldest female of a resident orca community family group; the matriarch is the leader over multiple generations
orca dialect — two orca groups using the same calls with only small variations are said to "speak" the same dialect
pod — a group of related orcas lead by a matriarch; pods may include the adult male and adult female children and their young; animals in the same pod use the same calls
saddle patch — the pigmented skin found directly behind the dorsal fin; scientists use the shape and personalized markings on the saddle patch to identify individual whales
spectrogram — an image describing a sound; a spectrogram is a line graph showing the changes in frequency over time
Orcas are highly intelligent, socially organized marine mammals in the order Cetacea, a group that includes both dolphins and whales. Although known as "killer whales," orcas are actually the largest species of dolphin. They have large brains and tightly knit societies. Widely distributed as a species, distinct populations of orcas are found in all of the world's oceans. Interestingly, each of these communities is characterized by its own unique set of behaviors, leading biologists to debate the idea of orca cultures.
Beyond differences in pod size, range and food preferences, the various orca communities exhibit different social structures, group foraging strategies and vocalization patterns. Many orca researchers believe these differences extend beyond the opportunistic use of different resources in their local habitats and represent traditions (learned behaviors that persist from generation to generation). But for all their differences, one element remains consistent across communities. Orcas are peaceful, cooperative and communal organisms.
Orca physiology allows these animals to perceive their environment using sound waves. A series of air passages and a unique organ called a melon enable orcas to emit a concentrated pulse of sound, termed clicks. These sound waves reverberate back to the whales as echoes, creating a sensory picture used to navigate and locate food sources. Orcas also use calls and whistles to communicate. A whistle is a constant tone, and a call is a distinct pattern of sound characterized by changes in frequency over a short period of time. Since each pod produces its own specialized calls, these vocalizations have become useful tools for marine biologists as they track the location and behaviors of different groups.
Scientists use hydrophones, underwater microphones, to record the calls. Spectrograms, which are graphic pictures of the different calls, help biologists create catalogs of the different vocalizations. Careful analysis of these pictures has revealed that related pods produce similar calls, sometimes with small variations to the end pattern. This consistency of sounds is considered a dialect. Pods that speak the same dialect are considered part of the same clan.
Biologists have established a standardized way to describe and identify individual whales based on high-resolution black and white pictures of the dorsal (top) fin and the saddle patch (pigmented patch behind the dorsal fin). Subtle differences in the shape of the dorsal fin and the saddle patch act as a whale fingerprint. Longer, straighter fins typically belong to adult males, whereas females and juveniles have smaller, slightly curved dorsal fins.
The best-documented orca communities are found living along the Pacific Northwest coast and Alaska. Three distinct groups, the northern resident orcas, the southern resident orcas and the transients have overlapping ranges, though have never been seen interacting. Even within the same waters, these three orca groups share few behavioral adaptations. A little known fourth group, the offshores, also shares some of this range. Even within the same waters, these orca groups share few behavioral adaptations.
See the Orca Community sheets for more information on each population:
- Northern Resident Community
- Southern Resident Community
- Orcas in New Zealand
Cut up each spectrogram sheet into five strips of three squares. Shuffle all of the strips and place them in an envelope.
(Note: Spectrogram sheets are based on a class size of 25 students. Make additional copies if class size is larger. Hand out fewer strips from each sheet if class size is smaller. Each spectrogram sheet represents a different pod. Pods 1 and 2 share a similar call and, therefore, are from the same clan. Pods 3 and 4 also share a similar call and are from the same clan. Pod 5 is unrelated to any of the other pods.)
- Ask students what they know about culture. What does it mean? What defines culture? Tell students that they will be exploring four orca communities and discussing whether, due to their differences, they can be considered different cultures. Inform students that they will be participating in the Orca United Nations. Explain that the United Nations is an assembly of representatives from different cultures and that each nation has its own customs and traditions.
- Pass out the Orca Vocalizations student worksheet and read together as a class, reinforcing the vocabulary. After students complete their descriptions of the two sounds represented by Spectrogram A and Spectrogram B, invite them to share their descriptions with the class.
- Introduce the term behavioral adaptation (any action or response that increases an organism's chances for survival). Break down the word and ask students for examples of behavioral adaptations.
Examples of behavioral adaptations in orcas:
Watch the "Orcas Hunting" video (4 minutes 55 seconds) at http://www.pbs.org/kqed/oceanadventures/video/orcas/. Talk about the different food sources and strategies used by the various orca communities. Discuss how these foraging behaviors help different groups survive in their environment and capitalize on the cooperative nature of orca society. Also discuss how these feeding behaviors are examples of each population of orcas having a set of unique behavioral adaptations.
Tell students, "For the Orca United Nations, you will be orcas from different communities. In order to find the members of your pod, you will be using what you know about orca calls. You will be receiving a sheet with three spectrograms representing three different calls. Your job will be to compare your calls with the calls of your classmates to find your pod. Remember,
- Orcas sleep by swimming side by side in synchrony while one whale remains more alert. This formation provides protection for the whole group.
- In some groups, young female orcas are designated the special role of babysitter for the young in the pod. This role gives future mothers firsthand experience and frees other members of the pod to hunt and search for food.
Hand out the spectrogram strips. Allow students to move about the room comparing their sounds until they find the other members of their pods. Ask students to gather in different areas of the room as pods form.
Discuss the ways each pod is related or not related to the other pods based on their calls. Ask students to identify which pods are from the same clan. Ask students what information they used to identify these relationships.
Hand out the Orca Identification student worksheet to each student to read and complete. Talk about how scientists are able to learn more about orca communities by identifying individual animals. (Additional images of orcas can be found at the Center for Whale Research website (at whaleresearch.com)
- Members of the same pod make the same calls;
- Members of the same clan make some of the same calls;
- Members of different communities make completely different calls."
Answers for Orca Identification student worksheet
|Adult male||Adult female|
Assign each pod of students a different orca community: southern residents, northern residents, transients and New Zealand orcas. You may want to assign the northern resident community to two groups. Distribute the appropriate Orca Community student handouts, a sheet of chart paper and markers to each group. (Explain that the relationships they uncovered among their pods using the spectrograms don't carry over to these new groups.)
Have students read the background summary specific to their group to learn about their orca community.
Hand out the Orca Pod student worksheets. Explain to students that they will first need to identify who they are in their pods and then draw a dorsal fin that conveys their identity and position in the pod. Then as a group, they will create a banner using symbols, pictures, diagrams and text to represent their community, following the directions on their worksheets.
Give students 30 minutes to work in their pods and then gather the class back together for a U.N. assembly. Have students present and explain their banners and dorsal fin pictures.
After all the groups have presented, brainstorm a class definition for culture and record ideas on the board.
Next, post the following question and ask for students' thoughts and ideas: Do the differences we see in orca society represent different orca cultures?
End with a discussion on the endangered state of orcas worldwide. Discuss the importance of preserving all of the different orca groups based on their unique behavioral adaptations and cultures.
Have students research the different threats to orcas worldwide, such as bioaccumulation of toxins, reduction in food supplies brought on by overfishing, water diversions, sea lice and global warming.
RELATED RESOURCES FROM JEAN-MICHEL COUSTEAU: OCEAN ADVENTURES
Whale Watcher Game lesson
Students take on the role of an Ocean Adventures expedition member in charge of filming various gray whale behaviors as the team follows the whales on their annual migration, in the Web-based game Whale Watcher.
Parasite Perils Data Analysis Game
In this activity, students collect and analyze data that explores the correlation between the presence of fish farms and mortality rates in wild salmon runs adjacent to the fish farms.
Call of the Killer Whale Viewing Guide
The Center for Whale Research
National Marine Mammal Laboratory, Alaska Fisheries Science Center
The Vancouver Aquarium
The Whale Museum, "Frequently Asked Questions about the Whales"
American Cetacean Society, Orca Fact Sheet
Seattle Aquarium, "Orca Whale Curriculum Background Information"
Te Ara - the Encyclopedia of New Zealand, "Orcas"
National Science Education Standards Grades 5-8 (at www.nap.edu)
Life Science --
Content Standard C:
Regulation and Behavior
Populations and Ecosystems
Diversity and Adaptations of Organisms
OCEAN LITERACY ESSENTIAL PRINCIPLES AND FUNDAMENTAL CONCEPTS
Essential Principle #5: The ocean supports a great diversity of life and ecosystems.
ABOUT THE AUTHOR
Amy O'Donnell is a science curriculum specialist for Columbia University's Center for Environment, Economy and Society and an independent contractor for KQED Education Network. KQED Education Network uses the power of KQED Public Broadcasting to inspire learning by providing projects for youth and curriculum materials and professional development for teachers, child-care providers and families.
Special thanks to John Ford for the use of the black and white spectrograms and high-resolution dorsal fin photographs. Brooke Nelson,
Community Conservation Liaison of the Seattle Aquarium (http://www.seattleaquarium.org), generously offered her insights and
expertise about orca communities. We also greatly thank NOAA's Alaska Fisheries Science Center for sharing ideas from
their "Saving Springer" curriculum to adapt for this lesson (http://www.afsc.noaa.gov/outreach/teacherresources.htm.)
Jean-Michel Cousteau: Ocean Adventures is produced by KQED Public Broadcasting and the Ocean Futures Society. The corporate sponsor is the Dow Chemical Company. Additional major support comes from the Richard and Rhoda Goldman Foundation, KQED Campaign for the Future, and the Corporation for Public Broadcasting.