Learning about marine mammals, or sea mammals, is important for understanding the impact they play in marine ecosystems. Marine mammals are quite amazing because they are similar to land mammals, but have adapted to aquatic life in order to survive. While these animals do not share a common ancestor, they do share several characteristics that classify them as marine mammals, such as:
- The need to breathe air
- Being warm-blooded
- Having mammary glands that produce milk in order to feed their babies
- Giving birth to live young
- In some cases, having hair
Interesting Facts About Sea Otters
Sea otters are one of the smallest marine mammals in the ocean. They grow to about four feet long and can weigh about 65 pounds. They prefer to live near rocky shores and kelp forests, and some will come onto the shore occasionally, but they can actually live all their life in the ocean.
- Why do otters have fur?
- Unlike most marine mammals that use blubber to stay warm in the cold ocean waters, sea otters rely on their extremely thick fur. In fact, sea otters have the world’s finest and densest fur—up to a million hairs per square inch! In comparison, you probably have about 100,000 hairs or fewer on your whole head. Sea otters use their fur to trap air, which helps them stay warm, but they have to keep it clean, because dirty hair will not hold air.
- How do otters stay warm?
- Besides their dense fur, sea otters use their feet to reduce or maximize heat loss when water temperatures are too cold or too hot, respectively. To reduce heat loss when the waters are cold, they float on their backs with their feet out of the water. When the waters are warm, they extend their feet out underwater to maximize their surface area.
- What do otters eat?
- Sea otters are carnivores, and their typical diet includes fish, crabs, clams, and octopuses. Sea otters prey on a variety of sea animals, and this can end up influencing the marine ecosystems that they live in. For example, they prey on sea urchins, which reduce grazing pressure. This allows kelp bed forests to grow and increase marine fauna density and diversity, which aids in the development of new ecosystems.
- How do otters eat?
- Sea otters dive down into the water to catch their food, sealing their nose and ears to keep the water out. Once they are back at the surface, they roll onto their backs and put the food on their stomach, like a plate on a table, and use a rock to help them crack open their food. Just like people, sea otters use tools to help them eat, because some of the foods, like clams, have hard shells that can’t be eaten.
TeachersPayTeachers Marine Life Lessons and Activities for grades K–3
Grades K–2
- Use these picture cards to help your students identify and learn about different types of marine mammals.
Grades 1–2
- In this “Read and Understand Science” unit for grades 1–2, you can help teach your students how sea otters adapted to the habitat in which they live.
- A fun reading activity to do with your class is this readers’ theater unit on a hungry octopus who steals food from three sea otters.
Grades 1–3
- Marine ecosystems are full of diverse animals, and a fun way to explore the different types of animals with your class is by doing one of these four ocean animal art projects.
- Learn about life in and around oceans with this science unit on Living in an Ocean, Spanish and English versions. Topics include animals without backbones, mammals, seabirds, and plants.
- Practice sequencing with this matching activity on otters and fish: Sea Otter Reading Worksheet for Sequencing for grades 1–3.
Sea Otter Protection Programs
Some aquariums, like the Monterey Bay Aquarium, have programs to help endangered marine life recover from the threats that affect their populations. The Sea Otter Program is one example: they help rescue, treat, and release injured otters or look for homes for those otters that can’t return to the wild.
The Monterey Bay Aquarium Sea Otter Program also raises and releases stranded pups through a surrogate program. This is important, as it connects to the concept that, in many kinds of animals, organism survival is dependent on what parents pass down to their offspring. Parents engage in behaviors that help the offspring survive, so stranded pups need the guidance of a surrogate to teach them how to live in the wild.
You can learn more about the Sea Otter Program by visiting the Monterey Bay Aquarium website. Be sure to check out the daily sea otter feedings on their live cam. You can also find suggested science units on marine life under their “lessons” tab.
You can also head to the education link on their website for more live videos and marine life activities.
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Mineko Inouye currently works as the project lead for the Marketing and Communications department at CSU Long Beach. Before moving into Higher Ed, she worked as an afterschool teacher/site supervisor at an LA-based learning center. There she could see that students throughout LAUSD were learning at different paces based on their school, so she avidly used instructional workbooks like Evan-Moor’s to help bridge the gaps between her students. She’s thrilled to be assisting Evan-Moor’s marketing communications team. She loves the company because they, like her, will always be passionate about helping students learn.