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Project title or topic of activity

Thermoregulation in Marine Mammals

Author(s): Angela Gauthier, Patti Lucas, Alisha Edwards, and Kim Ledford

Date: Spring 2001


Summary of Activity

Students will learn how mammals maintain a fairly constant body temperature under various conditions. Specifically they will become aware of marine mammals and their utilization of blubber through a hands-on activity.


Grade levels

This activity is designed for grades 3-5. It can however be modified to make it simple enough to perform in first and second grade classes.

Background information

The students will be asked to call upon their previous knowledge of mammals in order to assist them in understanding the activity. This will be accomplished through the use of pictures of marine mammals such as, walrus, polar bears, dolphins, whales and seals. Students will also look at pictures of mammals that live in warm climates (tigers, elephants, giraffes) and animals that live in cold climates (wolves, elk, snow hares). These pictures will all be presented to the students on cards. Each student will receive a card and be asked to discuss that animal’s characteristics. Example questions include: What is the animal? Where does the animal live? What is the climate like where they live? How does this animal cool off/warm up? When all of the cards have been explained the students will be asked what all of the animals have in common. This will be the characteristics that all mammals share. After viewing the pictures the students will be able to make the connections between mammals and their characteristics and will recall their previous knowledge and information given in this station. The discussion will lead the students into concluding that the characteristics of mammals are that they are warm blooded, give live birth, have hair, breath air and have lungs, exhibit parental care, have mammary glands, and have a placenta. After establishing the fact that mammals are warm blooded the students will review ways that mammals can maintain a constant body temperature in various environments. Some things that the students could come up with are that when the animals are hot they can pant, sweat, become lethargic, etc. When animals are cold they can shiver, lie in the sun, and increase their activity level. The presenter will ask the children to compare and contrast land mammals such as elephants, dogs, tigers, and kangaroos to marine mammals. The presenter will then propose the question, "how do mammals that live in the ocean keep warm?" This will guide the discussion to the use of blubber in thermoregulation. The students will learn that blubber is a fatty layer of insulation that can be found in marine mammals. We can compare where the student’s insulating layers can be found (arms, legs, stomach) to where it is found in marine mammals, which is over the entire body, directly under the skin. Blubber helps to streamline the body. This reduces drag when swimming and diving. Blubber can also serve as an energy reserve when the animal is fasting. This is useful to seals and sea lions that fast for three months during the breeding season. Walruses and seals have blubber that is a few inches thick. Ask the students how thick they think the blubber is on a whale. The answer is that it is two feet thick on large whales. An interesting thing to discuss with the students is that when seal pups are born they have very little blubber. They rely on long hair to keep them warm until their blubber develops. They also rely on metabolizing brown adipose tissue (fatty tissue). This is the same tissue that human babies use to keep warm!

Credit for the activity

The idea for the activity was obtained from the discovery channel website. (http://www.discovery.com) It was slightly modified to include more precise directions and more background information.

Estimated time to do the activity/activities

The total time for this activity can be adjusted depending on the grade level and the amount of background information that is presented. To complete the entire activity as presented here it takes approximately 35-40 minutes.

Goals of Activity/Activities:

  • Students will learn the characteristics of mammals.
  • Students will understand what blubber is and its function in marine mammals.
  • Students will become more familiar with the process of making observations and recording data.


Materials Needed

    1. Pictures of animals on small cards
    2. Vegetable Shortening
    3. Gloves
    4. Alcohol Thermometer
    5. Bowls
    6. Ice
    7. Paper towels
    8. Water

Preparation & teacher "heads up"

It is a good idea to have things set up before the students arrive. The instructor should make place settings at each table for the student to sit at by placing a paper towel at each place. Also have gloves at each table, a container of Crisco, icy water, and extra paper towels. Setting up is easy and should only take about 5-10 minutes.

Step-by-Step Procedure

The experiment will integrate the student’s knowledge of mammals and their thermoregulation by being an active participant in this activity. The experiment is designed to allow students to explore thermoregulation though a hands-on procedure.

    1. Divide the group of students into smaller groups (3-4 in a group).
    2. Next the two groups will each be given a large bowl filled with water, ice and rubber gloves. The students will be directed to place the ice in the bowl, creating an arctic-ocean environment. The students will wait three minutes for the water to chill. While they are waiting they will be instructed on how to use the student data sheet, which is self-explanatory, and each group will be given a sheet.
    3. After the water has chilled, the students will take the temperature of their water and record that data in the appropriate box on the data sheet.
    4. The students will then place one glove on either of their hands. They will take turns having one student place their hand in the water for thirty seconds and telling the other students how it feels. For example, does his or her hand feel cold? Does it hurt at all? How do you feel? The other students will record these observations on the data sheet. When everyone has finished experiencing the water temperature they will move onto the next phase.
    5. Dry off the wet gloves and then liberally apply vegetable shortening to their gloved hands. A second glove will be added to represent the dermal layer, which covers the insulating blubber of marine mammals. Once again the students will take turns placing their hands in the water for thirty seconds, making observations and recording observations.

Images, work sheets, additional web pages

Student Data Sheet

Students Name

Water Temperature

Observations w/out shortening

Observations with Shortening







































Items for discussion or conclusion


During the discussion of the results the students will be engaged in answering questions related to the experiment.

    1. What was the difference between the first time their hand was in the water and the second time? Why did it feel different?
    2. Possible responses: The first time there was no insulation….

    3. What does this experiment show about the function of blubber?
    4. Possible responses: Blubber acts as an insulator for mammals…

    5. Besides blubber, what are some other physical characteristics that help keep animals warm in cold climates?
    6. Possible responses: Fur, hair, behavior, metabolism…

    7. Think of some animals that live in cold climates and some that live in hot climates. Compare and contrast their physical characteristics.
    8. For this question the students will be presented again with the pictures of the mammals that were shown to them at the beginning of the station. They will pick a few to discuss.

      Possible responses:




    * hair

    * hair

    * warm blooded

    * warm blooded

    * fat reserves

    * fat reserves

    * give birth

    * give birth




    * sustains swimming and diving for long periods of time

    *short bursts of energy

    * can’t live away from water

    * can’t live in water

    * blubber layer

    *fat layer

  1. Humans have a layer of fat under the skin, but not enough to keep us warm. How do humans keep warm in cold temperatures?

Possible responses: clothes, manipulate temperature, move into the sun…

The wrap up will help bring closure to the station while giving the students a chance to review what they have learned. A good way to incorporate this will be to let the students explain in their own words what they have learned while the presenter cleans up the station. If time permits, students will be encouraged to ask any additional questions.

This lesson should teach students the basic principles of thermoregulation. The activity is simple and can be used to demonstrate an important marine mammal adaptation. Blubber plays a very important roll in the lives of marine mammals. It serves as an energy resource during fasting, streamlines the body, and most importantly, acts as an insulator.


The questions provided in the section titled "Items for Discussion or Conclusion" should initiate and promote conversation. The student’s responses and participation in this discussion should serve as an assessment as to how much they learned and retained from the activity.


Beyond the Activity
Further activities which relate to and extend the complexity of the experiment.

There are a few things that can be added onto this activity. First of all, there can be a quick discussion comparing heat loss in water and in air. The following activity can be used to illustrate the concepts behind this:

The presenter will lead into the activity by asking, "Do you think it’s easier to lose heat in water or air?" Then the presenter will perform a demonstration to help show that heat is lost in water more quickly than in air. The demonstration entails taking two 50mL beakers and filling them with hot water. Then the water temperature is measured in both beakers and recorded. One of the beakers is set on the counter at room temperature. The second beaker is placed into another beaker that is filled with water that is at room temperature. An original observation will be made to see which is cooling faster, and then the beakers will be left until the end of the experiment and a final observation will be made. The results will quickly be discussed. If for some reason, results other than what were expected occur, the presenter can ask why that is and reasons for error can be discussed.

Another simple addition to the activity can be used to compare the different ways that marine mammals keep warm. As discussed in the main activity, they can use blubber. But some marine mammals, such as sea otters, need to rely on other means to keep warm. They use their fur. Air gets trapped between their hair and forms tiny chambers of air that help insulate the body. A quick way to add this in would be to get a mitten made of synthetic rabbit fur, or the like, and have the students put that on a hand and submerge it in the water. Have the students determine which type of insulation works better. Do they think that different forms of insulation correspond to what climate the animals live in?

Web Resources
A web address with information on the topic of the activity.

Web Address

http://school.discovery.com/lessonplans/index.html : This is the discovery channel website for teachers. It has lesson plans broken down by grade level and subject. The template for this activity can be found in the lesson plans for K-5, titled "Underwater Animals."

http://www.britannica.com/eb/article?eu=51638&tocid=0 : This is a nice website to get quick facts on mammals.

Additional References


Campbell, Neil A. Biology. 4th ed. New York: The Benjamin/Cummings Publishing Company, INC., 1996.

Castro, Peter and Michael Huber. Marine Biology. 3rd ed. Boston: McGraw Hill Co., 2000. 


Spanish keywords

Thermoregulation = Termorregulación

Walrus = Walrus

Whale = Ballena

Marine mammal = Mamífero marino

Blubber = Grasa de ballena

Elephant = Elefante

Tiger = Tigre

Fur = Piel

Hair = Pelo

Warm = Caliente

Cold = Frío

Climate = Clima

Characteristics = Características