Activity #1: How Sea Otters Thrive
Sea Otter Insulation
The water temperature in Glacier Bay is about 37°-50° F. Sea otters don't have a lot of body fat (blubber) like seals and whales, but they do have very dense fur. In fact their fur is the thickest of any animal in the world and it allows them to maintain their body temperature.
Briefly, ask students to respond to the following questions:
Answer: Answers will vary. Accept all insulating possibilities as long as they can support their suggestion with reasonable data and/or experience.
Experiment: Insulating Properties
Answer: Answers will vary depending upon the material tested, the quantity of insulating materials and the conditions under which the materials are tested.
Next, ask teams to run another experiment to test the insulating ability of air. The directions for the experiment are on Student Handout 2: Air as an Insulator. When they have completed the experiment discuss their findings:
Answer: Students will discover that the balloon that has air will keep their fingers warmer than the balloon without air. The down vest is a good example of other insulators that use air, in this case between the feathers. Also, in many houses air is trapped between two layers of material and becomes a fairly effective insulator.
Sea Otters Fur Background
Share the following information with students:
Otters don't live in the air as we do. The down vest tested in Step 2 would keep them warm as long as it had a waterproof outer layer because down works by trapping air between feathers. The air-filled balloon is both waterproof and uses air as a fairly successful insulator. In Glacier Bay human divers use dry suits made of neoprene that trap a layer of air between their skin and the suit when diving in the Bay's cold waters. Otters also have a unique and very effective "covering" to keep them warm beneath the frigid waters of Glacier Bay.Have students read about sea otter's fur, using the Resources below so that they can explain how otters' fur keeps them warm and dry in the frigid water in which they live. Then ask students to:
Describe the sea otter's fur, both the outer coat and underfur. Include color(s), measurements and density.
Explain the reason why the sea otter’s fur is able to insulate the animal from extreme cold.
Explain why sea otters are constantly grooming their fur.
US Fish and Wildlife Service: Marine Mammals Management: Sea Otters: History of the Sea Otter http://alaska.fws.gov/fisheries/mmm/seaotters/history.htm
Return of the Sea Otter
Sea otters, Kelp and Killer Whales
Wikipedia – Sea Otters
The 2 sites that follow are excellent and very readable sites on sea otters. However, they both fail to state that sea otters are now found in healthy populations in SE Alaska, such as Glacier Bay National Park and Preserve.
Otternet: Species Profile – Sea Otter
Young People's Trust for the Environment: Otter (Sea)
Wise Old Sea Otter Activity
Have students complete this activity by writing a paper or staging a presentation, written by or led by a "wise old sea otter of Glacier Bay," about the science of staying warm below the waters of the bay.
What does a typical cold water drysuit look like?
How does a dry suit keep a person warm?
Why Dive Dry?
Cold Water Diving Wearing A Drysuit is Fun
Wikipedia: Diving Suit
The sea otter, a marine mammal, has adapted to an environment that would be impossible to sustain the human mammal. An even more difficult environment for a marine mammal, perhaps, would be the intertidal zone.
Have students research to discover what animals live within the intertidal zone. Are any of them mammals? What adaptations might a mammal have to make to survive in this constantly changing environment? They should design and illustrate an intertidal mammal that is perfectly adapted to the rigors of the intertidal zone and label or model the necessary adaptations.
Did You Know?
Glacier Bay has a maritime climate, heavily influenced by ocean currents. The result is mild winter and cool summer temperatures at sea level. Summer visitors can expect highs between 50-60F. Winter lows rarely drop into the single digits.