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Orca Connections

In this activity, the connection between terrestrial mammals (humans) and open water marine mammals (orcas) is investigated through the comparison of traits. Students will compare and contrast features of orcas with themselves.

Orcas, also known as killer whales, live mainly in deep, open ocean water, but are also often found close to the shore. While orcas are smaller compared to other whales, they are very large compared to land animals. Some adult males can have having dorsal fins up to 2 metres tall!

Orcas:

  • are mammals
  • are the largest members of the dolphin family
  • breathe air
  • live in families called pods, led by females
  • can live up to 70–80 years
  • eat 50–150 kg of food a day, depending on size and energy needs
  • are voluntary breathers and need to be at least half awake at all times
  • communicate with each other through vocalizations.

Each Orca pod has its own collection of calls (dialect), which is almost like a language.

Orcas use calls to find each other in the water, but how do they find their food in dark murky waters? By using echolocation; a series of high-pitched clicks. Orcas send out clicks through their fatty "melon" brow. The clicks bounce off objects and come right back onto the orcas' lower jaw. By using echolocation orcas can determine sizes, shapes, and distances of objects, as well as communicate with each other.

Southern resident killer whales, found in the waters of southern British Columbia, are protected as a Species at Risk with the classification Endangered because there are less than one hundred whales in the population.

Issues affecting the Southern resident orcas include:

  • declining fish populations for food
  • toxic exposure through water pollution
  • surface impacts such as commercial shipping, fishing, whale watching and pleasure boating
  • underwater noise that causes communication interference and sound pollution
     

Objectives

  • Identify the habitat of orcas.
    Describe adaptations and needs of orcas.
    Identify orca as a “Species at Risk” and explain the term.
    List and describe human impacts on ocean environments.
    List and describe ways in which we all can be ocean stewards.

Materials

  • Orca Vocalizations (If you don’t have access to the Internet, you can download orca sounds here and save them to play later.)
    Orca model such as a stuffed animal or photo
    replica killer whale tooth (Bone Clones)
    scale
    slinky
    string or masking tape

Key Questions

  • How are orcas like humans? How is the body of an orca specialized to live in the open ocean?

What To Do

SIZE:
Measure out and mark with tape or string the length, width, and height of an orca:

  • 7 m long 
  • 2 m wide
  • 1.75 m “tall” with a fin up to 1.8 m on top

Would it fit in the classroom? Compare to the size of a student. Compare the size of students’ teeth to the size of an orca tooth (3–4cm tall from gum to tip).

SOUNDS:

  1. Ask each student to close their eyes and pretend that they are an orca.
  2. Play a recording of orca vocalizations from the British Columbia Killer Whale Adoption website. Explain that these are the sounds of their family communicating with them.
  3. Assign different groups of students to listen to the recordings of different pods. Can they identify “their” pod?

ECHOLOCATION:

  1. Stand holding one end of the slinky while one student holds the opposite end still (about 1.5 m away).
  2. A second student volunteer plays Chinook salmon (approximately 70 per cent of Southern resident orcas’ diet comes from Chinook.)
  3. Have the Chinook pinch about 4 coils of slinky in the middle and hold it still. 
  4. While holding one end of the slinky, pretend to be an orca and explain how you are sending out a series of clicks trying to find your food. As you make clicking sounds, send pulses through the slinky. These pulses will bounce back after reaching the student in the middle, demonstrating how the sound waves produced by an orca bounce off objects in the water, and return in the form of echoes. 

FOOD:

  1. Using a scale, have a few students weigh their lunch. 
  2. To estimate the amount of food they eat in a day, multiply this amount by 4.
  3. Compare the result with the amount an orca eats in a day (50–150 kg/day.)
  4. What does 100 kg of food look like? If you’re collecting donations for the food bank, weigh the results.
     

Extensions

  • What other animals communicate or find food by echolocation? What kinds of environments are best for using echolocation? How does what we do on land affect orcas? What makes orcas different from other whales? What is another example of a species at risk?

Other Resources

Science World Resources | Unit | Coastal Connections
Engaging Science Online Games | Secrets @ Sea
Smithsonian Magazine | Understanding Orca Culture