Tendons Store Energy

Biological Strategy

Bushbabies and galagos

AskNature Team

Image: Richard Mortel / Flickr / CC BY - Creative Commons Attribution alone

Capture, Absorb, or Filter Energy

Energy is naturally available in many forms, including kinetic, potential, thermal, elastic, radiant, chemical, and more. All living systems require energy to carry out their many activities, and have developed strategies appropriate to one or more of those forms. For example, some plants maximize their surface area available for capturing radiant energy from the sun while others have strategies to focus scattered light onto photosynthesizing areas.

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Store Energy

Once a living system captures energy or transforms one energy form into another, it must frequently save that energy for future use. But energy is difficult to store in some forms. So living systems need strategies to either use energy quickly, or to convert it from forms that are difficult to store (such as electrical or kinetic) to more storable forms. For example, grasshoppers store energy as potential energy in an elastic material in their tendons. When they need to jump, that energy converts into kinetic energy, providing the force needed to escape predators.

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Distribute Energy

Many forms of energy are naturally available, including kinetic, potential, thermal, elastic, radiant, chemical, and more. All living systems require energy to carry out their many activities. Energy isn’t a physical object that can be held, so it also can’t be pushed, pulled, or carried. However, it can be transmitted or transformed. For example, the golden-scale snail has a tri-layered shell that dissipates, or transfers, forces from a predator biting down on it, thereby minimizing damage to its soft body inside the shell.

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Mammals

Class Mammalia (“breast”): Bats, cats, whales, horses, humans

Mammals make up less than 1% of all animals on earth, but they include some of the most well-known species. We know first-hand some of the characteristics that make mammals unique, like having hair, being able to sweat, and producing milk through mammary glands. Another critical shared feature is a set of highly-specialized teeth. Unlike sharks or alligators, for example, whose teeth are generally all the same size and shape, mammals have differently shaped teeth in different areas of the jaws to target specific foods or foraging strategies.

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The legs of the bushbaby allow it to jump twelve times its body length by storing energy in tendons.

These agile creatures can leap swiftly between the branches of trees in woodland and savannah regions of Africa south of the Sahara and on nearby islands. They are small (18 cm/7 in.) primates with thick, wooly fur and large eyes. One remarkable feature of the bushbaby is that it can jump up to 2.25 m (7 ft.), which is 12 times its body length! The bushbaby accomplishes this feat with the help of extremely strong, stretchy tendons in its back legs. When a bushbaby prepares to leap, it uses muscles to stretch those tendons and store elastic energy in them. Then when the bushbaby jumps, those tendons release their stored energy like catapults to help the animal spring forward. A long tail helps give the bushbaby control during the leap.

This strategy was co-contributed by EcoRise Youth Innovations

Last Updated March 16, 2018

References

“Bushbabies (Galago senegalensis) are renowned for their phenomenal jumping capacity…Most of the power required for jumping is delivered by the vastus muscle–tendon systems (knee extensor). Comparison with the external joint–powers revealed, however, an important power transport from this extensor (about 65%) to the ankle and the midfoot via the bi–articular calf muscles. Peak power output likely implies elastic recoil of the complex aponeurotic system of the vastus muscle…It is argued here that the multiple internal connective tissue sheets and attachment structures of the well–developed bundles of the vastus muscle become increasingly stretched during preparatory crouching and throughout the extension phase, except for the last 13 ms of the push–off (i.e. when power requirements peak). Then, tension in the knee extensors abruptly falls from its maximum, allowing the necessary fast recoil of the tensed tendon structures to occur.” (Aerts 1998:1607)

Journal article