Adventures With Otters

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1 Grades 4 5 Adventures With Otters Otter Versus Otter bit.ly/toptalentepi6 Unit 6 Which animal is Georgia Aquarium s top talent? You decide! It s otter against otter before a panel of three penguin judges as sea otters and an Asian small-clawed otter demonstrate social behavior and eating habits. These amazing animals provide an otter-ly chaotic competition in the Aquarium s Top Talent video presented by Georgia-Pacific. Next Generation Science Standard: Structure and Function, 4-LS1-1 Plants and animals have both internal and external structures that serve various functions in growth, survival, behavior and reproduction. Both the sea otter and Asian small-clawed otter have structures to help them survive. These playful animals have streamlined bodies that make them strong swimmers. They eat about a quarter of their weight every day to fuel their bodies, which is one way they keep warm. When they dive beneath the surface, their hearts slow and they close their noses and ear canals. The sea otter actually uses rocks as tools to break open shellfish for food. WORDS TO KNOW grooming: to clean and keep up the appearance social: living or growing in groups or communities solitary: growing or living alone INTRODUCING THE LESSON: 1. Write the following sentence on the board: I am known for doing a lot of ing, ing, ing and ing. Have each student write on scrap paper four verbs ending in -ing to describe actions he often takes, such as reading, snacking, talking and running. 2. Provide time for students to share their verbs. Then announce that if you were an otter, you would say I am known for doing a lot of grooming, eating, playing and swimming. Then explain to students that they ll be learning about two special members of the otter species: the sea otter and the Asian small-clawed otter. Tell them that the sea otter, from the North Pacific Ocean, is solitary and spends all its time in the water. The Asian small-clawed otter is social and lives in family groups. The smallest type of otter, it spends only about half its day swimming, because its small body loses heat easily in the water. Both types of otter spend much of their time grooming, eating and playing.

2 Grades 4 5 Adventures With Otters Designed Fur Warmth Next Generation Science Standard: Structure and Function, 4-LS1-1; Information Processing, 4-LS1-2 Plants and animals have both internal and external structures that serve various functions in growth, survival, behavior and reproduction. Different sense receptors are specialized for particular kinds of information, which may then be processed by the animal s brain. ESTIMATED LESSON TIME: minutes MATERIALS: 4 balloons 2 large cups ice water ruler Background Information: Otters have two layers of fur. A thick layer of fine underfur traps air next to an otter s skin. This insulates the otter from cold water temperatures. Thicker guard hairs form a waterproof topcoat. Sea otters use their whiskers to sense changes in the water current and to find food. WORDS TO KNOW The stiff hair on Asian small-clawed otters snouts and elbows also helps them locate prey and sense water turbulence. dense: thick insulate: to prevent the transfer of heat turbulence: in a state of being disrupted underfur: the thick, soft layer of fur beneath the longer, coarser hair of a mammal Lesson: 1. Have each student use a ruler to draw a one-inch square. Next, have the student draw lines (hairs) on the square inch. Direct her to count the hairs she drew and write the number beside her drawing. 2. Explain to students that otters have double-layered coats of fur. Tell them that the sea otter s underfur with up to one million hairs per square inch is the densest fur in the animal kingdom. Have students look at their square inches and compare their numbers to one million. To give even more perspective, share that the average human has about 100,000 hairs on his entire head. 3. Explain that the sea otter s fur traps a layer of air against the otter s skin. To show how air insulates the animal from cold water temperatures, have student partners complete the experiment steps.

3 Grades 4 5 Adventures With Otters EXPERIMENT STEPS 1. Fill both cups with ice water. 2. With your partner s help, slip a balloon halfway up one index finger. Make sure the balloon fits tightly around your finger. Then slightly inflate the second balloon and have your partner help you slip it halfway up the index finger on your other hand. 3. Place each finger covered by a balloon in a different glass of water. Determine which finger feels warmer: the finger covered by the deflated balloon or the one with the slightly inflated balloon. 4. After all students have completed the experiment steps, ask which finger felt warmer and invite them to consider why it felt warmer. (Students should report that the finger covered by the slightly inflated balloon felt warmer. The air in this balloon insulated the finger from the cold better than the uninflated balloon did.) 5. Help students realize that a layer of air in an otter s fur insulates the otter s body from the cold just as the air in the balloon insulated their fingers. Explain that, to protect its insulating qualities, an otter spends quite a bit of time cleaning its fur every day. In fact, some sea otters spend as much as half a day grooming, cleaning their fur after eating by rolling in the water and rubbing it with their paws and then fluffing it with air bubbles. 6. As a follow-up, have students research other ways that sea otters and Asian small-clawed otters have adapted to survive in their different environments. DID YOU KNOW? Although they don t use tools like sea otters do, Asian short-claw otters sometimes carry small pebble toys in their armpits. When they re playing, they juggle the pebbles with their paws!

4 Name Date Interdependence in ecosystems (5-LS2-1) Two Special Types of Species Read the information in the chart. Then read each statement on the right. Write each statement s letter in the chart to show whether it is an example of a keystone species or an indicator species. a. Alligators live in swamps in the southern United States. They use their snouts and tails to dig holes to live in. During dry periods, these holes are often the only areas that still have water. Species such as frogs, insects, fish and crustaceans move in with the alligator so they can survive the drought. keystone species: any plant or animal that is important for the survival of other living things in an ecosystem indicator species: any plant or animal that can show the health of an ecosystem. When an indicator species is doing well, it means the ecosystem is healthy. If the species dies or moves away, it means the ecosystem has problems. Sea otters are an important keystone species in a kelp forest. Kelp is a type of seaweed. Sea urchins eat kelp, and sea otters eat sea urchins. This keeps the sea urchin population from growing so large that it destroys the habitat. Sea otters are an indicator species. They eat animals that are filter feeders. Filter feeders may collect toxins, such as those from pollution, in their systems. They pass these toxins on to sea otters. If the sea otter population isn t doing well, it shows there is a problem in the habitat. b. When a beaver builds a dam that blocks a stream, the overflowing water can change a dry stream bank into a wetland. This creates a new habitat for other species, such as dragonflies, herons and frogs. c. Mangrove trees grow in some wetlands. Their large roots provide a place for many species to lay eggs. Birds, manatees, fish and crustaceans feed among the roots. If mangrove trees were to disappear, the swamps would not exist. d. Dragonflies buzz around wetlands, eating other insects. If dragonflies disappear, it shows there is a problem with the wetland. e. Elephants live on Africa s savannas, or grasslands. They feed on the trees there. If they did not, too many trees could grow and destroy the grasslands for many different species. f. Snails eat algae. If there is a great deal of water pollution, algae won t grow. If a snail population in a habitat is large, scientists know that there is plenty of algae and that the water quality is good. Bonus: Design a poster to encourage others to protect sea otters. Use the information in the chart to help you.

5 ADVENTURES WITH OTTERS Two Special Types of Species ANSWER KEY keystone species: a, b, c, e indicator species: d, f Bonus: Answers will vary.

6 Name Date Structure and function (4-LS1-1) Otters Big and Small Sea otters and Asian small-clawed otters have a lot in common. For example, they both have webbed feet and long bodies that are perfect for swimming. They also have very thick fur that keeps them warm. These two animals also have some interesting differences, like their size. Sea otters are the heavyweights in the otter family. Males can reach 90 pounds. Asian small-clawed otters are the smallest otters. They weigh up to 11 pounds. Read on to learn more. Where They Live Sea otters live in shallow waters along the northern Pacific coast. Most of them are in Alaska. They rarely leave the water and live in forests of giant kelp, a type of seaweed. Asian small-clawed otters are found in India, China, Indonesia and the Philippines. Besides the ocean, they also live in ponds, lakes, rivers, swamps and even rice fields. They spend more time on land than most otters. They burrow into muddy banks and make homes there. How They Socialize Sea otters float in small groups called rafts. Females stick together and avoid males except when mating. Sea otters rest on their backs and wrap themselves in kelp to keep from floating away. They stick all four feet out of the water, which looks comical. Actually, their feet have little or no fur, so heat escapes quickly. Holding them out of the water keeps the otters body temperature normal. Asian small-clawed otters form strong family ties. They live with at least a dozen other otters. These groups are called lodges. Males and females mate for life. Both types of otters communicate by growling, snarling, cooing, whistling and other sounds. Each sound has a special meaning, like an alarm or a greeting. Playfulness is another common trait. Both types of otters have been seen sliding down embankments over and over! Answer the questions. 1. True or false? Otters bodies are adapted for swimming. 2. Sea otters float together in small groups called while Asian small-clawed otters live in groups called. Asian small-clawed otters 3. Why do sea otters float with their feet out of the water? 4. What characteristic makes the Asian small-clawed otter different from most otters? 5. Name two things both types of otters have in common. Sea otter

7 ADVENTURES WITH OTTERS Otters Big and Small ANSWER KEY 1. true 2. rafts, lodges 3. Keeping their feet out of the water helps keep their body temperature normal. 4. They spend more time on land than most otters. 5. Possible answers include that they both have thick fur, have webbed feet and long bodies, live in groups, make sounds to communicate, and are playful.