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Engineering: Sea otters

Sea otter swimming

Fun Fact

Sea otters have pockets under their forearms, where they store food and their favourite rocks.


Who doesn’t love sea otters? And, now I know they have pockets and favourite rocks, I love them even more! Otters are tool users. They select special rocks that are suitable for cracking open clams and molluscs and store these rocks in the baggy pockets of loose skin they have under each forearm.

What tools do humans use? Check what the children think of when they hear the word tool. Many people will think of hammers, saws, maybe gardening tools, but tools are generally defined as hand-held devices that are used to fulfil a specific task or function. Together with the children, think about which tools they use in their daily lives, such as scissors or pencils.

What’s the STEM?

Children realise that a tool is any object that helps you complete a job. Spotting common tools in their environment creates an awareness of the role engineering plays in our everyday life. The use of tools was once thought to be a way of distinguishing humans from animals but many animals, including quite a few marine animals, use tools too. Learning about this increases children’s appreciation for the abilities and rich diversity of animal behaviour.


You can use this handy overview of simple machines [pdf] to guide your search for everyday tools.


Go on a tool hunt. What examples of tools you can discover around your service, school or at home?

Interesting facts for adults

Sea otters

Sea otters are the heaviest member of the weasel family and, although they are able to walk on land, they spend most of their time in the water and even sleep floating on their backs. They are inventive in their use of tools to get to their food, using smaller rocks to crack shells or prise abalone off rocks and larger ‘anvil’ stones to open mussels, by placing them on their chests while floating on their backs or using stationery anvils along the shore.

Other animals that use tools:


Chimpanzees are humans’ closest living relatives and have learned how to make and use tools long ago without human help, with stone hammers found at a chimpanzee settlement in the Ivory Coast dating back 4,300 years.


A group of bottlenose dolphins in Shark Bay, WA, carry marine sponges on their beaks to stir ocean-bottom sand and uncover prey, spending more time hunting with tools than any other animal besides humans. Their behaviour is particularly interesting as they are using another animal (a sponge) as a tool and they are learning this trick from each other. No bottlenose dolphin outside of this group has been observed hunting like this.


An octopus that uses coconut shells as portable shelter is the latest addition to a growing list of tool users in the animal kingdom. Veined octopuses collect discarded coconut shells and carry them around so they can later use then as mobile protection when needed.

These new findings are apparently the first reported instance of an invertebrate that acquires tools for later use.


Increasingly, scientists find that crows and their relatives have exceptional birdbrains, proving extraordinarily adept at crafting twigs, leaves and even their own feathers into tools. In Aesop’s fable, the crow drops stones in a pitcher of water to raise its level, enabling the crow to drink when it couldn’t reach the bottom of the pitcher before. Researchers have discovered that crows may really be able to learn behaviour as described in the story.

Observations, conclusions and extensions

Once you start, you will be amazed by the number of tools you find. For which purposes do you need the tools you found? Talk about the examples of the animals who use tools. What do they accomplish with their tools? In addition to the “regular” tools that we use for their specific purpose, for example, cutting up paper with scissors, we also improvise a lot. We substitute simple tools all the time, for example, we might use a ruler to rip a page in a straight line rather than scissors. Or we might knock a nail in with a rock or use a spoon to prise the lid off a tin. What other creative uses of tools are there? Be inventive!
Hayley Bates
Article author: Hayley Bates
National Certifications Coordinator

Hayley has an insatiable thirst for learning – about everything! Her sheer joy of discovery and passion for professional development makes her the perfect person to run the Little Scientist’s House Certification program.

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