Killer Whales

Why are killer whales difficult to study? How have killer whales adapted to feeding on different types of prey?

This audio is part of the One Species at a Time series hosted by Ari Daniel and produced by Atlantic Public Media and the Encyclopedia of Life, with the support from the Harvard Museum of Comparative Zoology. Licensed under Creative Commons Attribution 3.0.

Story Length: 5:30

Download transcript of audio.

Download and print this lesson plan.

  • Objectives

    Students will know and be able to…

    • Discuss pros and cons of choosing to study killer whales.
    • Describe the purpose of different types of vocalizations of killer whales.
    • Discuss adaptations for feeding that are observed in killer whales.
    • Answer questions about killer whale behavior by producing and interpreting graphical information.
  • Student Background

    This lesson requires no additional information. This could serve as the introduction to discussions of feeding behavior and adaptations.

    Vocabulary terms:

    Ambush- to attack by surprise from a hidden place

    Echolocation- a process used to locate objects using reflected sound waves

    Pod- the term for a group of killer whales

    Predator- an animal that consumes another animal for food

    Prey- an organism that is used for food by another animal

    Resident populations- groups of killer whales that regularly live in the same area

    Transient populations- groups of killer whales that only spend a short time in any one location

    Vocalizations- sound produced with the voice of an organism

  • Materials

  • Lesson Plan

    One Species at a Time Podcast: 5:30

    1) Listening Guide

    Biologists studying killer whales face the challenge of studying organisms that spend the majority of their time underwater.  This story and accompanying materials and lessons explore the difficulty of studying killer whales and emphasizes the reasons that scientists are willing to work so hard to study them.  In addition, the story discusses adaptations that different populations of killer whales have evolved to capture prey.

    2) Listening Prompts for Students

    a. Why do the researchers enjoy studying killer whales?

    b. Where do killer whales live?  Why does that it make it difficult for biologists to study killer whales?

    c. What do killer whales eat?  Are there differences in the diets of killer whales living in different places?

    d. How does the feeding behavior of killer whales feeding on fish differ from that of killer whales feeding on seals and porpoises?  What is the reason for that difference?

    e. How do the researchers in the podcast locate dolphins in order to study them?

    f. Do you think you have the patience required to be a killer whale biologist?

    3) Play the One Species at a Time Story

    4) Reading Guide

    Killer whales, orcas, are the largest member of the dolphin family.  They are highly social animals that live in groups and rely on heavily on sound to locate their prey and communicate with other killer whales.  Killer whales eat a wide range of prey and use different strategies to capture different types of prey.

    5) Reading Prompts for Students

    a. What do scientists call a group of killer whales?  How many individuals typically live in a group?

    b. What types of sounds, or vocalizations, do killer whales use?  What is the purpose of each type of call?

    c. What types of food do killer whales eat?  What is a hunting strategy that killer whales use to capture fish?  What is a hunting strategy used by killer whales to capture marine mammals?

    d. How does the pod size vary between killer whales hunting for fish and killer whales hunting for marine mammals?

    6) Read the Encyclopedia of Earth Article (focus on the sections on Behavior and Food habits)

    Orca Whales

    7) Watch Video (38 sec)

    Nothern Resident Orca vocalizations.WWF Canada.

    8) Lesson

    Total lesson time: 90 minutes

    Listening time: 5:30

     

    Class Activities:

    1. What would it be like being a biologist that studies killer whales?

    Put students in small groups of 2 – 3.  Have each group discuss the good aspects and bad aspects of studying killer whales.  Have each group come up with a list of three good things and three bad things about studying killer whales.  Have each student write a paragraph answering the question- “Would you like to study killer whales? Why or why not?”

     

    2. How do killer whales capture their food?

    Killer whales are social hunters (hunt in groups) and their hunting strategy varies depending on the type of food they are eating.

    Have students discuss how killer whales use vocalizations to capture their prey.   What is the purpose of “clicks”?  What is the purpose of making other calls when hunting prey?  Why would killer whales feeding on fish benefit from using clicks, calls, and whistles?   Why wouldn’t killer whales feeding on dolphins and whales make sounds while hunting?  What other senses could killer whales feeding on seals and dolphins rely on?  Discuss other adaptations killer whales have to catch food.  Have students write a paragraph discussing feeding adaptations of killer whales.

    Have students discuss the costs and benefits of hunting in groups.  What are some examples of animals that hunt in groups and what are examples of animals that hunt alone?  Discuss reasons these differences in hunting strategy.  How can killer whales benefit from feeding in groups?  Why might killer whales choose to feed in different sizes of groups when feeding on different types of prey?

     

    Extension:

    Researchers studying killer whales around Vancouver Island in British Columbia, Canada have observed that transient pods may break up into smaller groups while hunting marine mammals.  When they discovered a group of killer whales, scientists followed them for as long as they could and documented the number of times that the killer whales successfully captured food.  Note: the scientists were unable to spend the same amount of time observing pods of different sizes.

    This data was taken from the article “Ecological and social determinants of group size in transient killer whales”.  By Robin W. Baird and Lawrence M. Dill. Published in Behavioral Ecology Volume 7, pages 408-416. http://www.cascadiaresearch.org/robin/BehavEco.pdf

     

    Group Size      Time Observed (hours)               Observed Number of Successful Prey Captures

    1                                  31.9                                         2

    2                                  41.9                                         12

    3                                  111.4                                       53

    4                                  65.8                                         15

    5                                  51.6                                         9

    6                                  42.4                                         18

    8                                  15.6                                         3

    9                                  13.2                                         0

     

    Looking at the Data

    1. Draw the graph that shows how the length of time scientists spent observing a group varied with pod size. (hint: think about what type of graph is most appropriate to display this information)

    Graph Interpretation Question:  What pod size was observed for the longest period of time?

    Biology Question:  If pods of different sizes were equally successful at catching prey, then which pod size should have been observed to catch the most prey?  Why?

     

    2. Draw the graph that shows how the number of successful feeding attempts depended on pod size?

    Graph Interpretation Question: Which pod size had the most successful captures?

    Biology Question: What are two possible reasons that scientists observed pods with three members capturing food more than any other pod size?  Think about how to distinguish between these two possibilities.

    Hint:   If killer whales are equally effective at capturing prey regardless of the size of the hunting group then we might expect to observe the most captures by the group size that we had observed the longest.  To determine which group size is best for catching prey then we would have to figure out which groups caught prey at the highest rate (that is, the number of successful captures/time observed).

     

    3.  Calculate the rate of successful captures per foraging time by dividing # captures by the observation time.  Draw the graph that shows how the rate of successful captures depends on pod size.

    Graph Interpretation Question:  What size of pods had the highest rate of successful food capture?

    Biology Question: The capture rate of pods with 3 and 6 members were very similar.  Do you think that it matters to the dolphin whether they are feeding in a pod of 3 or 6 members?  Which pod size do you think would be best?  Why?  How would you try to test your ideas?

     

    4. Using a fairly complicated formula, the scientists estimated the average amount of energy gained per day (measured as Kcal/kg/day) by killer whales feeding in groups of different sizes.

     

    Group Size      Average Energy Intake

    (# ind)             (Kcal/kg/day) 

    1                      31.9

    2                      41.9

    3                      111.4

    4                      65.8

    5                      51.6

    6                      42.4

    8                      15.6

    9                      13.2

     

    Draw the graph that shows how average energy intake depended on pod size?

    Graph Interpretation Question: Which pod size had the highest average energy intake?

    Biology Question: Which is the best group size for hunting marine mammals in this environment? Write one paragraph discussing your answer.

  • Homework Socrative Quiz

    Tell students to listen to the public radio story at home. Then assign a Socrative Assessment or written homework.

    socrative logo
    Short answer quiz: SOC-3937923

    Socrative.com allows you to give quizzes through any device or browser and get graded score reports immediately sent to you! To learn how to use Socrative shared quizzes, view this tutorial.

    Or tell students to listen to the Public Radio Story at home and answer the following questions:

    a. Why do the researchers enjoy studying killer whales?

    b. Where do killer whales live?  Why does that it make it difficult for biologists to study killer whales?

    c. What do killer whales eat?  Are there differences in the diets of killer whales living in different places?

    d. How does the feeding behavior of killer whales feeding on fish differ from that of killer whales feeding on seals and porpoises?  What is the reason for that difference?

    e. How do the researchers in the podcast locate dolphins in order to study them?

    f. Do you think you have the patience required to be a killer whale biologist?

  • Assessment Evidence

    Students’ written answers to questions and participation in group discussion.

  • Standards

    Common Core Standards: Speaking and Listening

    Grade 6

    CCSS.ELA-Literacy.SL.6.1 Engage effectively in a range of collaborative discussions (one-on-one, in groups, and teacher-led) with diverse partners on grade 6 topics, texts, and issues, building on others’ ideas and expressing their own clearly.

    CCSS.ELA-Literacy.SL.6.1a Come to discussions prepared, having read or studied required material; explicitly draw on that preparation by referring to evidence on the topic, text, or issue to probe and reflect on ideas under discussion.

    CCSS.ELA-Literacy.SL.6.1b Follow rules for collegial discussions, set specific goals and deadlines, and define individual roles as needed.

    CCSS.ELA-Literacy.SL.6.1c Pose and respond to specific questions with elaboration and detail by making comments that contribute to the topic, text, or issue under discussion.

    CCSS.ELA-Literacy.SL.6.1d Review the key ideas expressed and demonstrate understanding of multiple perspectives through reflection and paraphrasing.

    CCSS.ELA-Literacy.SL.6.2 Interpret information presented in diverse media and formats (e.g., visually, quantitatively, orally) and explain how it contributes to a topic, text, or issue under study.

     

    Grade 7

    CCSS.ELA-Literacy.SL.7.1 Engage effectively in a range of collaborative discussions (one-on-one, in groups, and teacher-led) with diverse partners on grade 7 topics, texts, and issues, building on others’ ideas and expressing their own clearly.

    CCSS.ELA-Literacy.SL.7.1a Come to discussions prepared, having read or researched material under study; explicitly draw on that preparation by referring to evidence on the topic, text, or issue to probe and reflect on ideas under discussion.

    CCSS.ELA-Literacy.SL.7.1b Follow rules for collegial discussions, track progress toward specific goals and deadlines, and define individual roles as needed.

    CCSS.ELA-Literacy.SL.7.1c Pose questions that elicit elaboration and respond to others’ questions and comments with relevant observations and ideas that bring the discussion back on topic as needed.

    CCSS.ELA-Literacy.SL.7.1d Acknowledge new information expressed by others and, when warranted, modify their own views.

    CCSS.ELA-Literacy.SL.7.2 Analyze the main ideas and supporting details presented in diverse media and formats (e.g., visually, quantitatively, orally) and explain how the ideas clarify a topic, text, or issue under study.

     

    Grade 8

    CCSS.ELA-Literacy.SL.8.1 Engage effectively in a range of collaborative discussions (one-on-one, in groups, and teacher-led) with diverse partners on grade 8 topics, texts, and issues, building on others’ ideas and expressing their own clearly.

    CCSS.ELA-Literacy.SL.8.1a Come to discussions prepared, having read or researched material under study; explicitly draw on that preparation by referring to evidence on the topic, text, or issue to probe and reflect on ideas under discussion.

    CCSS.ELA-Literacy.SL.8.1b Follow rules for collegial discussions and decision-making, track progress toward specific goals and deadlines, and define individual roles as needed.

    CCSS.ELA-Literacy.SL.8.1c Pose questions that connect the ideas of several speakers and respond to others’ questions and comments with relevant evidence, observations, and ideas.

    CCSS.ELA-Literacy.SL.8.1d Acknowledge new information expressed by others, and, when warranted, qualify or justify their own views in light of the evidence presented.

    CCSS.ELA-Literacy.SL.8.2 Analyze the purpose of information presented in diverse media and formats (e.g., visually, quantitatively, orally) and evaluate the motives (e.g., social, commercial, political) behind its presentation.

     

    Common Core Standards: Other Standards

    CCSS.ELA-Literacy.RST.6-8.7 Integrate quantitative or technical information expressed in words in a text with a version of that information expressed visually (e.g., in a flowchart, diagram, model, graph, or table).

    CCSS.ELA-Literacy.RST.6-8.8 Distinguish among facts, reasoned judgment based on research findings, and speculation in a text.

    CCSS.ELA-Literacy.WHST.6-8.2 Write informative/explanatory texts, including the narration of historical events, scientific procedures/ experiments, or technical processes.

    CCSS.ELA-Literacy.SL.7.4 Present claims and findings, emphasizing salient points in a focused, coherent manner with pertinent descriptions, facts, details, and examples; use appropriate eye contact, adequate volume, and clear pronunciation.

     

    Next Generation Science Standards

    MS-LS2-2. Construct an explanation that predicts patters of interactions among organisms across multiple ecosystems.

    MS-LS4-6. Use mathematical representations to support explanations of how natural selection may lead to increases and decreases in specific traits over time.

  • Other Resources

    Killer whales (Scientific name: Orcinus orca, also known as orcas) are a species of marine mammals from the order Cetacea (dolphins, porpoises, and whales).  In spite of their common name, orcas are not actually whales at all, but are instead the largest member of the dolphin family.   Cetaceans have a number of adaptations to allow them to live in the sea including streamlined shape, powerful tails and fins for swimming, echolocation for finding prey, and blowholes on the top of their heads to allow them to breathe.  Orcas are predators that feed on a variety of animals.  Killer whales live in groups called pods and often members of a pod work together when hunting for prey.

    Orca

    These articles can help provide context for the information about killer whales:

    Oceans

    Marine mammal

    Cetacea

    Marine biomes

    Biome

    Predation

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