PACIFIC LIFE WHALE EDUCATION KIT - LESSON 4

Whale Communication and Echolation

Goals/Objectives:

Students will:

• Understand the value of sound as a means of "seeing" underwater.
• Demonstrate how whales may use sound to keep in touch with each other and their surroundings.
• Gain an appreciation for the complexity of whale communication.

Teacher Overview:

Students engage in a variety of activities showing how whales communicate.

Time: 45-50 minutes (Each activity is approximately 10 minutes)
Setting: Indoors and Outdoors
Subjects: Science, Visual Art and Math
Key Words: Echolocation, High frequency, Low frequency, Songs, Pod

If you dive deeper than twenty five feet in the ocean you will notice that 90% of the light from the surface is gone. Some of the sunlight gets reflected back into the air, some of it is turned into heat (have you ever felt warmth from light coming through a window?) and some of it is blocked by suspended mud, pollution or plankton in the water. Therefore, whales can't rely on their eyes to find food or to communicate under all circumstances. Instead they use sound. Sound travels five times faster in water than in air!

Whales don't have vocal cords like we do, but they appear to have membranes of similar form which may serve the same purpose as vocal cords. They produce sounds by forcing air from their nasal passages into sacs, without exhaling any air. It is believed the sounds are made in the throat or larynx. After taking a breath of air, they can reuse that air several times to make sound before exhaling it.

Whales use a mechanism called echolocation to "see" with their ears. They direct a beam of click-like sounds and listen to the echoes that return from objects in the path of the sound. If you direct a flashlight at something in the dark, you illuminate the object with light and you can see it. Whales can "illuminate" a silent fish with sound in order to "see" it. From the returning sound, the whale learns the size, shape, speed and direction of the subject. Dolphins can even beam their sound waves into mud to find hiding fish! (Seawater and flesh have approximately the same density so the sounds whales emit penetrate the flesh of submerged animals. It has been suggested that whales can actually see the inside of their companions and their prey. The resulting image might look like an ultrasound picture). Fish can't hear the high pitched sounds so they don't realize they are being observed. It has been postulated that some whales may even use strong pulses of sound to stun their prey! (see Zoobooks. Dolphins and Porpoises, and Whales for graphic descriptions).

Toothed whales generally spend most of their time in shallow, coastal areas and use sharp, high frequency sounds that don't travel very far through the water before being converted into heat. Short, high-pitched, rapid sounds used on objects in close proximity allow whales to hear the finer details. Some types of baleen whales (like blue and fin whales) spend a lot of time in deep, dark waters, using loud, low frequency, long-ranging sounds to communicate and navigate the seas. Low frequency sound can travel for long distances, but only gives broader details. The distance traveled depends largely on the depth and temperature of the ocean the sound is sent from (temperature and pressure change the conductive properties of water).

Fin and blue whales are examples of loud-voiced whales. They are larger baleen whales that are found in all oceans. While humpback, right, bowhead and gray whales have specific breeding grounds, so far no one has found a breeding ground for the rorquals other than the humpback. Fin and blue whales may not need a distinct breeding ground. They may just start calling with their loud, low songs to potential mates. These calls can travel for hundreds and even thousands of miles. It is not out of the question to assume that the calls may also contain information about where food is.

Humpback whales make rhythmic, repeated patterns of sounds or songs. Their songs (sung mostly by males) seem to be related to mating and may function the same way bird calls do, as a challenge by males to other male rivals and as a means of attracting females. Suspended head down in the water, very still, humpbacks can sing for hours. All humpbacks sing the same song on the same breeding ground even if they are very far apart. The lowest sounds in their songs are audible over long distances.

Other possible forms of communication that whales employ are breaching, lobtailing and flipper slapping, which may be ways of sending sounds intended as communication at short range through the water. They could be saying, 'I'm over here!"

Materials:

• CD player
• 'Deep Voices' CD
• 4 Blindfolds

Before Class:

1. Position the 'Deep Voices' CD to where you want to start it. (Recommend starting at # 3: Blue and right whale sounds)
2. Have blindfolds ready.

During Class:

Have 'Deep Voices' CD playing when students enter classroom. Remind them that whales have special adaptations that help them to do everything underwater even though they breathe air like us. One of the most important adaptations whales have developed is their ability to image their surroundings.

Explain the use of sound as a method of seeing underwater. Whales seem to use sound to locate food, as an aid in navigating through the vast ocean, as a way to keep in touch with one another and as a means to attract a mate. Scientists believe that some whales can use sound not only to see objects underwater, but to look right inside them, like Superman with X-ray vision!

Activity 1: Full of Hot Air (5 Min.)

Discuss how scientists think whales produce sound underwater. Whales produce the loudest sounds made by any animal! While scientists know that some whales produce these sounds without releasing air, just how they do it remains a mystery. When humans communicate verbally we expel air, whales do not. This activity demonstrates that some whales produce sounds underwater without releasing air.

1. Have the students take a deep breath, plug their nose and try to communicate with another student without releasing any air. Give 2 minutes to this play activity.

Activity 2: Pod Squad (10 Min.)

This activity demonstrates the great density of information contained in sound.

1. Have the class form a circle facing inward.
2. Blindfold one student and put him or her in the middle of the circle.
3. The person in the middle of the circle will be trying to identify other people in the circle using sound only.
4. Spin the blindfolded person twice, then point him or her at someone in the circle. That person is to say, 'Hi _____' (blindfolded student's name) in his/her normal voice. (Try to pick one student who is known well to the subject and someone who is not.)
5. Using this information, the blindfolded student is to make his/her best guess at who is talking to him/her, then respond 'Hi ______' (the name of who he/she thinks it is)

Let several students try, giving each the chance to identify a few classmates. Discuss the following questions with the class.

• Although each person in the circle said the same two words, were students surprised with their success in identifying people in the circle?
• What were some of the things that they could tell about the speaker, just in those two words? (Male or female, age, identity, are they sick or healthy, were they smiling or laughing, are they a friend, where are they?)

Using sounds of many types, whales can determine many things about each other and their surroundings without having to use their eyes (100 foot visibility underwater is extraordinarily rare. Much of the time the underwater world is too dark and murky for them even to see their own tail, it is simply too far away.)

Activity 3: Pod Up! (10-15 Min.)

Take the class to an area outside or in the auditorium. Tell them that you will now be playing an activity to demonstrate how different species of whales use their own sounds to keep in touch with members of their pod, herd or group.

1. Whisper into the ear of each student the species of whale that they will become for this activity (for example, you might want to choose 10 dolphins, 5 orcas, 3 humpbacks, and 2 fin whales-choose the loud kids to be fin whales). Tell students to keep their species a secret until it's time to play the activity.
2. Explain that each species will have a voice. When the activity begins, they are to use this voice to locate members of their own kind and form a pod. Give them the following voices: Dolphin: whispers 'dolphin', Orca: in a high, squeaky voice, 'Orca', Humpback: sing at normal voice level 'humpbaaaack', Fin Whale: Shout at the top of their lungs 'FIN WHAAAALE!'
3. Using these voices, students are to 'Pod-Up' with other members of their own species. Members of each pod should stay as far apart as possible, but still be able to hear every member of their species.
4. Spread students out on the field and give them three minutes to play the activity.
5. Gather class for wrap-up. (If indoors, point out that a real life fin whale would be 70 feet long. Compare to auditorium)

Like song birds, each species of whale uses a different type of sound to communicate with members of its own species. High frequency sounds can contain more detail than low frequency sounds, but don't travel very far underwater. Low frequency sounds used by fin whales are some of the loudest made by any animal on earth and allow them to communicate over vast distances (over 1000 miles, possibly up to 4000 miles!). This also dictates how close to one another animals need to be to keep in touch. Dolphins form tight groups in large numbers, while fin whale pods may be scattered as widely as the area of an entire ocean!

Activity 4: Telegraph (Rainy day or indoor alternative to Pod-Up!)

Gather students into a circle. Explain that they will be playing one more activity about communication. It may be an activity they've played before, but today it will demonstrate an important idea about the way different species of whale may form pods.

1. Whisper a short story into one student's ear. That student will then quietly whisper the story to the person on his/her left, say it only once and not repeating any part of it. That student will then whisper it quietly to the person on his/her left and so on until the story has made it all the way back around to the first person.
2. The last person to hear the story will say the new story out loud.
3. The teacher will say the original story aloud as well and together the students will list the errors that were made. (If some students have played this game before and decide to introduce errors intentionally just for laughs, you can offer the class some prize for transmitting the story correctly.)
4. Now try speaking a story aloud to the class. Ask several members of the circle to repeat it back to you aloud.
5. Was this method more accurate?

Explain to the students that whale scientists believe that whales are also aware of this difference. Some whales, like dolphins, have developed very high-frequency sounds that appear to be used as contact calls for keeping together. These sounds don't travel very far underwater before becoming too faint to hear. Therefore, the pods that can be formed by using these sounds are very dense with many animals close together so everyone can hear whoever is the sender. Fin and blue whales on the other hand, have developed voices so low and loud that they may be able to hear each other 1000 miles away, perhaps much farther across deep water. This means that a single pod of fin whales may conceivably be spread across an entire ocean and therefore may contain a great many animals.

Teacher Wrap-up:

As we've seen today, whales are believed to use sound to learn vital information about their environment and each other, information their eyes can't provide them with. Large whales, like fin whales, can see huge areas of ocean. Some have acoustic abilities so finely tuned that they may be able to look right through a swimming human to see the skeleton, organs and even babies in the wombs of their mothers. In the case of the humpback whale, some of the sounds they make are so eerily like our own music that musicians have used them as an inspiration for their own works. These are the behaviors that we know least about and may teach us the most about another intelligence on earth that is not like our own. Learning about these behaviors is something that today's students may contribute to in the future.