Biomechanics | The Field Museum

Burr Biomimicry

After going for a walk through the Swiss Alps in 1941, electrical engineer George de Mestral noticed burrs stuck in his dog’s fur. As he untangled them, he noted the tiny barbs at the end of the burr’s spines and was inspired to create a fastener made of hooks and loops.

After he patented Velcro in 1955, it spread like wildfire—even to space. NASA was among the first to make use of the burr’s technology. A two-inch (5-cm) square of Velcro is secure enough to hold 175 pounds (80 kg)—or keep astronauts’ tools from floating away.

Ebb & Flow

Trees don’t use pumps to transport fluid. Instead, as water evaporates from the leaves, a vacuum is created that pulls water upward from the roots via tiny vertical tubes called xylem.

In the spring, trees grow wider xylem to transport more water and nutrients to the growing leaves. The widest xylem are only half a millimeter across. Together, they can lift several hundred gallons of water in one day to the top of the world’s loftiest trees, some which measure more than 300 feet tall.

Heating Up & Cooling Down

Animals regulate their body temperatures in surprising ways:

A Toucan can radiate more than half of its heat out through its beak when it’s too hot. But it must tuck its beak beneath its wing to keep from getting chilled while sleeping.
A Horned Lizard can hold heat in its sunning head using an unusual arrangement of blood vessels that divert warmed blood to its body when it’s time to get moving.
An Eider Duck can paddle its feet in frigid waters without ever lowering its core body temperature, via a circulatory system that recycles heat.

Heavy Hitters

The Stone Crab’s power-grip secret is leverage. Its crusher claw—the larger, stouter one—can deliver a pinch that measures 6,600 pounds per square inch (45,500 kPa)!
The Harpy Eagle’s power-grip secret is sharp pressure points. Talons concentrate all the force of the leg muscles onto a handful of high-pressure points, with the largest talon measuring 530 pounds per square inch (3,650 kPa).
The Mantis Shrimp’s power-grip secret is speed. Its spring-loaded claw swings forward at the rate of a speeding bullet, creating a shock wave that does double damage to its intended dinner.

Big Biters & Swift Snappers

Crocodiles have the biggest bite force of any living creature. While they mostly eat fish, the largest ones can take down giraffes, Cape buffalos, and small hippos.
The Piranha—the champ of bite force for size—is able to bite with a force 30 times its own weight. That would be like a human biting down with the weight of an SUV!
The Wood Stork wades in shallow pools with its open bill in the water. When an unfortunate fish swims through, it snaps its bill shut in just 25 milliseconds.
The Longnose Gar has the most elongated jaws of any fish. As young gars grow, their jaw proportions lengthen and they switch from feeding on slow crustaceans to fast fish.

Posture Affects Pace

Over time, animals on different branches of the tree of life have developed various walking postures that affect their speed:

Modern amphibians, like the first walkers on land 160 million years ago, drag their bellies and wriggle across the ground with their legs out to the side.
Reptiles can push off and run with less spinal bending because, although their knees still point outwards, their bellies don’t drag on the ground like their sprawling ancestors.
Mammals hold their knees under their bodies, a more efficient and versatile posture. That’s how they have evolved a variety of different gait patterns and speed, from a walk to a trot to a gallop.

Same Function, Different Story

Just because they all have wings and flippers, doesn’t mean they’re closely related. The different internal structures of these fliers and swimmers tell us about their separate evolutionary histories:

Bird's fingers are fused together so that they flap their whole arm in flight, with motion at their shoulder, elbow, and wrist.
Bats can move their fingers independently, which allows them to change the shape of their wing and turn sharply at a moment’s notice.
Pterosaurs supported their wing with their pinkie finger, leaving the rest of their hands free to grasp and climb.
Insects, which have no bones, possess wings made of grids of 4-, 5-, and 6-sided shapes. The hexagons allow the wing to flex, while the rectangles stay rigid.
Dolphins evolved from mammals that once walked on land. Their finger and thumb bones still remain inside their flippers.
A sea lion’s fingers end in claws, telling us they’re more closely related to bears than to dolphins, which have no claws.

Super Senses

Some animals take ordinary senses to new heights:

Hearing: the Saw-whet Owl can hunt in complete darkness (unlike other owls), due to its lopsided ears. It takes sound longer to reach one ear than the other, adding an additional dimension to the predator’s hunting precision.
Communicating: the male Club-winged Manakin can sing like many other birds, but to attract a mate, he “plays” his wings by clapping them together, creating a loud, clear tone like a violin string.
Touching: the Venus Flytrap uses trigger hairs to detect whether it has attracted a meal or a mistake. One bent hair might be rain, two hairs tickled might be an insect, more hairs moved may mean a live dish, making it worth the energy to snap solidly closed.

Paralympic Sprinters

Legs—whether we have two, four, six, or hundreds—let us skitter and jump across the Earth’s uneven surface. Gravity pulls us down with each step, but our momentum and internal springs redirect this force to our advantage.

Scientists have long been working to mimic the complex biomechanics of a human leg, which use the Achilles tendon to store and release energy. The curved, carbon-fiber foot, while still not quite as efficient as a natural leg, possesses enough springiness that amputees can really run—and even compete in the Paralympic Games.

Domes in Nature

The right shape can boost your strength. For example, domes transmit force over their whole surface, helping bodies to withstand greater impact. So while eggshell is a thin, fragile material, its shape helps it withstand up to 90 pounds (40 kg) of downwards pressure before breaking.

Some domed creatures—like tortoises and horseshoe crabs—have stuck with this same shape for millions of years.

Worming along with Fluid Pressure

Worms have five hearts but no lungs. Instead, their hearts pump blood that carries oxygen absorbed directly through the skin.

But in addition to the pumping action of its hearts, a worm uses fluid under pressure to dig a path without the aid of a shovel. When muscles squeeze liquid-filled chambers along its body, the segments expand and contract to help the worm wedge its way through the earth.

Chilling Through Chimneys

Methods that animals use to control temperature have inspired many human innovations.

For example, the airflow in African termite mounds influenced the design of the Eastgate Centre in Zimbabwe. The building needs neither artificial heating nor air conditioning because the building relies on chimneys like those of the termite mound, which allow warm air to escape out the top while cool night is drawn in from the bottom. As a result, the building uses 90% less energy than a conventional building.

Dunkleosteus Model

Field Museum scientist Mark Westneat and metal artist John Zehren created this working, life-sized model of the extinct fish Dunkleosteus. After measuring forces in the model, they calculated the bite force of the living creature as 1,200 pounds (540 kg)—one of the strongest bites of all time.

The model replicates the unique mechanism of a Dunkleosteus skull: four rotational joints connected into a four-bar linkage system. This enable the fish to open its mouth in one-fiftieth of a second, creating a powerful suction that pulled prey into its mouth before biting down.

MABEL in Motion

Human gait is difficult to reproduce, because of our Achilles tendon, which releases energy like a spring as we run. MABEL runs upright, and can even recover from a stumble.

At 6.8 mph, MABEL is the world’s fastest two-legged robot with knees. Although she looks powerful, her most innovative feature helps her use less power. By building stretchy bands into her joints, her designers gave her the robot version of tendons.

MantaBot

Designed and built by Hilary Bart-Smith and her team at the University of Virginia, this robotic manta ray is so lifelike that real fish accept it as one of their own. Biologists can use it to quietly monitor the conditions of life at sea and check in on endangered coral-reef species.

Other robotic flyers in the exhibition include RoboSeed, which mimics a maple seed and can be used to explore hard-to-reach locations like unexplored caves. The four-flippered Madeleine helps scientists test theories about how these swimmers evolved.

Hammerhead Shark

Perhaps one of nature’s oddest-looking creatures, the Hammerhead Shark is a hunting machine. Their heads are packed with pores that sense electricity, given off by prey’s contracting heart muscles.

The sharks use their sensitive snouts to scan the sand along the ocean floor. When they come within range of a hiding creature, its pulse enters their pores and signals their brains for a shark attack.