Table of Contents
Welcome ...........................................................................................................................................1
Reporting for Service ................................................................................................................................ 1
Scheduling ................................................................................................................................................. 1
Logistics for Interpretative Cart ................................................................................................................ 1
Tips for Interacting with Visitors ............................................................................................................... 2
Logging Your Volunteer Hours .................................................................................................................. 2
Adding Yourself to the Schedule ............................................................................................................... 2
Introduction to the Idea of Animals: Machines in Motion ....................................................................3
Introduction to Biomechanics.............................................................................................................3
Chapter One: Built To Survive .............................................................................................................3
Staying in One Piece against Forces of Nature ......................................................................................... 3
Going with the Flow .................................................................................................................................. 4
Embracing the Elements ........................................................................................................................... 6
Chapter Two: Built to Move ...............................................................................................................9
Grabbing a Bite: Jaws and Claws............................................................................................................... 9
Crossing the Landscape: Legs and Springs .............................................................................................. 11
Wings and Fins ........................................................................................................................................ 12
Chapter 3: Built to Discover .............................................................................................................. 14
Venus Fly Traps ....................................................................................................................................... 14
Echolocation............................................................................................................................................ 15
Magnetoreception .................................................................................................................................. 17
Sue .................................................................................................................................................. 18
Bite .......................................................................................................................................................... 18
Eyes ......................................................................................................................................................... 18
Movement............................................................................................................................................... 19
Teeth ....................................................................................................................................................... 19
Page 1
Welcome
From the inside out, every living thing—including humans—is a machine built to survive, move, and
discover. The San Diego Natural History Museum’s latest special exhibition, Animals: Machines in
Motion, investigates the marvel of natural engineering from a cheetah’s sprint to a flea’s jump, from a
crocodile’s chomp to an owl’s hearing. Day after day, animals spring into action to bite, grab, jump, run,
swim, and fly after their next meal—if not, they quickly become one! And before they make their next
move, they must decode the mysteries of the world around them, using senses familiar and
unimaginable.
The following information is just basic background on these amazing animals. Let the exhibition be your
main source of information. If you read every panel you will know more than any visitor. Enjoy!
The exhibition runs from October 29, 2016 through Tuesday, January 2.
Reporting for Service
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Please wear dark pants, white shirt, your photo ID, and your “Ask Me” button. After working
three shifts, you’ll be eligible for a free t-shirt from the Museum store and you can wear that for
the remainder of the exhibition. There are several dinosaur-themed t-shirts.
Sign in the log at the north visitor desk and say hi to the VSAs.
Come to the volunteer room and leave your personal items in a locker. There are locks for your
use. The keys are located on the wall near the door. Take the key with you.
Please log your volunteer hours in Volgistics at the beginning of your shift. You may include
travel time to and from the Museum.
On your first day, plan on coming a little early or staying a little late so that you can thoroughly
explore the exhibition. This guide doesn’t cover everything that is in the exhibition.
Scheduling
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You may add yourself to any opening in the Animals schedule on Volgistics.
Shifts are 10 AM–12:30 or 12:30–3 PM.
A weekly shift is the desired commitment.
Logistics for Interpretative Cart
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The cart will be stored in the hallway behind the Emergency Exit door between the two
restrooms in the exhibition hall.
Please use care when moving the cart.
Please station the cart inside the exhibition hall. The visitor service staff will be taking tickets in
the lobby area. We don’t want to interfere with ticket taking.
Unless you are relieved by another volunteer, please return the cart to the storage area.
Please be gentle with the biofacts and keep them in your control at all times. You can allow the
visitor to handle the objects but keep a watchful eye.
The objects on the cart are self-explanatory. The tooth is a model of a T-rex tooth.
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Tips for Interacting with Visitors
Volunteers working the exhibition help us provide extra customer service for our visitors. Please follow
these guidelines:
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Share your enthusiasm for Animals: Machines in Motion.
Respect personal space and read their body language when approaching.
If a visitor is agitated or complains, please find the security officer in the exhibition.
Give them clear directions when explaining where things are located in the Museum.
Tell them about other exhibitions in the Museum:
o The Last Hurrah: The Photography of Abe Ordover (4th floor
o Extraordinary Ideas from Ordinary People: A History of Citizen Science (3rd floor)
o Skulls (3rd floor)
o Fossil Mysteries (2nd floor)
o Coast to Cactus in Southern California (2nd floor)
o Water: A California Story (1st floor)
Encourage them to visit other museums and gardens in Balboa Park.
Logging Your Volunteer Hours
Recording the number of hours you work as a volunteer is an important part of your service. These
volunteer hours play a critical role when the Museum applies for grants and submits proposals to
donors. Each year 750 volunteers contribute over 58,000 hours. The only way we can know how many
hours is by asking you to log them.
There is a computer in the volunteer room you can use each time you work your shift. If you forget to
log your hours, you can log them from home. Here are the instructions:
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Go to the Museum’s website www.sdnhm.org.
Choose the Join + Give Menu and click on Volunteer.
Click on the link that says “Already a Volunteer? Login here.”
Sign in using the email address you listed on your application. Your temporary password is
welcome. You will be asked to change it the first time you log in.
Choose Animals as your assignment.
You may include your travel time in your hours.
You may record your mileage for tax purposes (You may deduct mileage to and from your
volunteer work).
Adding Yourself to the Schedule
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Log into Volgistics as above.
Choose Check Your Schedule.
Choose show openings in Animals.
You may select any day with the Help Wanted sign.
Choose Schedule Me and then click continue to confirm.
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Introduction to the Idea of Animals: Machines in Motion
Imagine if your jaws could crush over 8,000 pounds in one bite, your ears could act as air conditioners,
and your legs could leap the length of a football field in a single bound. From the inside out, every living
thing, including humans, is a machine built to survive, move, and discover. Investigate the marvels of
natural engineering in Animals: Machines in Motion. In this exhibit, one will explore how plants and
animals stay in one piece despite the crushing forces of gravity, the pressure of water and wind, and the
attacks of predators. Using surprising tactics, creatures endure the planet’s extreme temperatures, find
food against fierce competition, and—without metal, motors or electricity—circulate their own lifesustaining fluids. Feel for yourself how hard a giraffe’s heart works to pump blood up to its head. Try to
“fly” and study the many different ways creatures jump, gallop, slither, and swim. And see technological
breakthroughs, like Velcro, wind turbines, and chainsaws, that were inspired by nature’s ingenuity.
Animals: Machines in Motion was developed by The Field Museum, Chicago, in partnership with the
Denver Museum of Nature & Science, with generous support provided by the Searle Funds at The
Chicago Community Trust and ITW Foundation.
The Exhibit narrative is broken down into three major Chapters:
1. Built to Survive
2. Built to Move
3. Built to Discover
Introduction to Biomechanics
Biomechanics is the study of the structure and function of biological systems such as humans, animals,
plants, organs, fungi, and cells by means of the methods of mechanics built by the forces of evolution.
Evolution is a change in allele frequencies in a population over time. The term evolution is commonly
used to refer to any heritable change in a species that occurs over a long period of time (i.e., many
generations).
The accumulation of these heritable changes over time may lead to the formation of one or more new
species. This exhibition takes visitors past the familiar surface of nature, and deep inside its remarkable
workings. It’s a story of survival, of using devices "finely-tuned” to every imaginable situation. Evolution
is Earth’s greatest innovator.
All living things respond to forces of the physical world. Evolution creates an enormous diversity of
biological designs that solves life’s challenges. Some are common strategies and some, cases of extreme
performance.
Chapter One: Built To Survive
Staying in One Piece against Forces of Nature
How do plants and animals manage to stay in one piece in a world where there are crushing forces such
as the pressures of water, wind, and blows of other creatures? No matter what day or time, we—living
things—are under attack. Wind, water, extreme elements, even gravity are constantly working to pull us
apart. In order to withstand these extreme forces of the world, all living things have evolved “the right
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tools for the job.” For example, trees, feathers, even bones are all made up of both hard matrix
materials and flexible fibers that allow them to bend and be strong at the same time. The bones in your
body are made up of both calcium and collagen, allowing
them to bend ever so slightly. Without that collagen, every
minor impact would send you to the hospital with a broken
bone.
And though the word “dome” might not sound that exciting,
the dome shape is found throughout nature, and provides
impact safety to a number of animals from a horseshoe crab
(carapace) and a tortoise (shell), to a human (skull) and a
bird (egg). In fact, the dome shape is so strong, chicken eggs can withstand 90 pounds of pressure
before breaking.
This section will also introduce visitors to the concept of biomimicry—when humans find inspiration in a
design found in nature. Nearly everyone has used Velcro; one of its first uses was in space, but now it
can be found on shoes, luggage, even your lunchbox. But did you know Velcro is impersonating burrs
found in nature? Uncover the story behind this modern invention and how it all began with a walk
through the woods with a family dog.
The Woodpecker
Its unique skull allows it to peck wood at a rate of 20 pecks per second without injuring its brain. If
humans were under such force we would have an instant concussion. Through the process of evolution,
woodpeckers have adapted specific anatomical parts to resist such forces.
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Thick and strong neck muscle protect the brain.
The upper part of its beak is longer and the lower is shorter but
stronger. This asymmetry lowers the load of force.
Its skull is made up of plate-likes bones that have a spongy
structure in the front and back of the skull that protect the brain
on impact.
Hyoid apparatus, or their tongue, wraps around their entire
skull in a Y shaped horn and acts as a safety harness when
pecking.
Its brain is small as compared to its body and fits tightly into its skull.
Question: how can we use the woodpecker’s biomechanics to inspire preventative measures to our
injuries? (Car crashes, Football helmets)
Going with the Flow
Inside every living thing, fluids like blood circulate with a precise pressure, speed and volume in order to
sustain life. How—without metal, motors, or electricity—do they manage to drain, pressurize, push and
recirculate these vital fluids?
While our bodies are fighting elements externally, internally another battle is being fought. We’re in a
never-ending race against time to distribute life-sustaining supplies to every cell in our body. Using the
power of pumps, pipes, and pressure, living things move air and fluids to where they’re needed most.
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Animals features five touchable heart models of a mammal, bird, reptile, amphibian, and fish; the hearts
vary in size and shape, but they are all pumps, using pressure to push fluid throughout the body. A
highlight in this section is a real giraffe’s heart, displayed next to a heart model that visitors can actually
“pump.” Raising fluid a great height (like blood to the giraffe’s brain) requires high pressure, so a giraffe
has a much higher blood pressure than a human.
But animals aren’t the only ones pumping vital resources throughout their bodies, plants are doing it as
well. However, trees aren’t using pumps to transport fluid; instead, as water evaporates from the leaves,
it creates a vacuum in tiny vertical tubes which pulls water upward from the roots. Visitors will be able
to examine the cross section of a tree to see the tiny tubes (xylem) that run from roots to leaves.
Spider Locomotion
Arachnid locomotion actually makes use of the same force that powers a variety of mechanical
instruments: hydraulics.
Hydraulics is the process whereby power is generated, controlled,
and transmitted through the use of pressurized liquids.
A remarkable and effective hydraulic mechanism is found in the legs
of spiders, which have muscles to flex the joints but none to extend
them. Spiders stretch their legs by pumping fluid into them. When a
spider gets ready to jump, it generates, for a fraction of a second,
excess pressure of up to 60% of the atmosphere. The legs extend in
order to accommodate more fluid.
To extend their legs, spiders rapidly increase pressure in their cephalothorax, the round, bulb-like
midsection to which all the legs are connected. This increase in pressure sends hemolymph (blood)
flowing to the extremities, causing the legs to stretch outward. When moving, spiders innately increase
and decrease body pressure in fractions of a second to quickly skitter about.
Far from only powering basic locomotion, hydraulics endows certain
spider species with prodigious jumping abilities. Jumping spiders can
leap more than fifty times their own body length by swiftly boosting
blood pressure in their third and fourth limbs. This is also the reason
why when you see a dead spider their legs are curled inward.
Giraffe’s Heart
The giraffe is the tallest land mammal at 18 feet. The heart is two feet
long and weighs up to 25 pounds. It can pump 16 gallons of blood per
minute. This means that the giraffe needs extremely high blood
pressure, twice that found in humans. It pumps about 170 times per
minute. It counteracts the force of gravity much like pumping water up
to a house.
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Question: What happens when it lowers its head to drink water? How
does its head not explode? Its neck has amazing valves and arteries that
release the pressure and equalize it as the giraffe lowers its head.
Other facts about the Giraffe:
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They can eat up to 100 pounds of leaves per day.
They sleep less than 2 hours per day and can do it standing
up.
They have a long flexible neck that has the same amount of
vertebrae that we have in our neck. It is flexible because of
its ball and socket joint like the ones we have that attach our
arm to our shoulder.
Redwood Tree
Trees use a different mechanism to move fluid upwards. There is a constant upward flow of water from
the roots to the topmost part of the tree. Scientists have discovered that water molecules interact with
the sides of the capillary tubes, that's the plumbing that carries
the water and nutrients up into the tree. This interaction
creates a bond which "drags" the water column up with it. At
the same time the water evaporating from the leaf creates a
vacuum which pulls the water up as well. At some point the
attraction and the tree's "suction" are not strong enough to
maintain this column of water with the result that the tree has
reached its maximum height.
Scientists and researchers estimate that a mature tree requires hundreds of gallons of water per day,
and for this reason the roots need an ample supply of water. Redwood trees thrive in the river bottoms
where they obviously have access to lots of ground water. But these giant trees also make their own
rain, out of fog. The moisture in the air condenses between the leaves and eventually drips down to the
root zone. It is believed that one of the reasons redwood trees have adapted to their great height is
because the higher the tree, the more moisture it can provide for itself. And the reason they thrive along
Northern California's Pacific Coast is because this area often gets a daily fog.
Embracing the Elements
Life on earth must endure the planet’s extreme temperatures. What strategies and mechanisms do
plants and animals use to keep warm in icy seas or keep cool in broiling deserts? Different habitats exist
all over the world: desert, rainforest, tundra, ocean, swampland and prairies are just a few examples. All
the plants and animals are impacted in that habitat. Humans and many other mammals have unusually
efficient internal temperature-regulating systems that automatically maintain stable core body
temperatures in cold winters and warm summers.
Insulation and Radiators
Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries,
even when the surrounding temperature is very different.
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Can you imagine cooling yourself using your ears? Or staying warm by letting your feet go cold? Animals
have evolved countless ways to maintain their body temperature in extreme climates using tricks of size,
shape, and innovative insulation. Here, visitors will learn about the Fennec Fox’s ears that keep it cool
using tiny blood vessels that help the animal pull heat from its body. Similarly, a toucan sends blood to
its bill when it gets too hot.
An interactive thermal camera will allow visitors to see how much heat they are losing at that every
moment. Visitors can see how different types of clothing keep heat in while others let more heat
escape.
Did you know that animals living in colder environments are larger than their counterparts in warmer
areas? Despite having less food and harsher living conditions, larger animals stay warm more efficiently
because they have a greater proportion of volume (which retains heat) to surface area (which loses
heat). Visitors will be able to see this for themselves. On display will be a model of a full grown whitetailed deer from the southern United States and another from Canada.
Toucan
With a big beak and small body, a toucan can radiate more than half of its heat out through its beak
when it’s too hot. At sunset, when the birds sleep, the temperature of the bill drops quickly by 10°. The
sudden swings in temperature could only be caused by the birds
using their beaks as a kind of radiator to remove heat from their
blood. Blood vessels flow close to the surface of the beak, where
air temperatures can cool it down. The more blood flows into the
beak, the more the toucan can cool down. This works so well it has
to hide its beak under a wing while it sleeps so it doesn’t get
chilled.
How can a toucan’s beak control its temperature? To keep warm
when it’s cool out, it only lets blood into the vessels near the base of its beak so only a little heat is lost.
To cool off when it’s warm out, it pushes warm blood into the blood vessels throughout the whole beak
so lots of heat is lost.
Termites
Termites are fragile creatures. They must stay moist at all times, so they cover their trails with dirt and
feces. They also make travelling tubes to protect themselves from ants and from the dry air. It is an
engineering marvel to prevent the sensitive termites from their greatest fear—becoming dehydrated.
Even in desert-like conditions, they require 90% humidity and the protection of underground tunnels.
Nests that are shaped like mountains are architecturally very complex. The construction of all the nests
begins underground, where compartments become more spacious as they approach the surface. A
cross-section of a termite nest would show that the inside resembles a sponge composed of countless
cells 2.5 cm (0.9 inches) in size, or smaller. These cells are joined by narrow passages only large enough
for termites to pass through. Termites thrive in an atmosphere whose temperature and humidity are
constant, with a carbon dioxide content of between 5 and 15%. In such an environment, human beings
would lose consciousness, but termites survive easily.
The structure is a massive complex of corridors designed to circulate air in just the right way, that is, to
eliminate CO2 and water and take in oxygen with just the right humidity. The termites use wind, solar
energy, north-south positioning, and extremely complex engineering to survive.
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Bergmann’s Rule
In 1847, the German biologist observed that within the same species of warmblooded animals, populations having less massive individuals are more often
found in warm climates near the equator, while those with greater bulk, or
mass, are found further from the equator in colder regions. This is due to the
fact that big animals generally have larger body masses with a smaller surface
area which result in more heat being produced. The greater amount of heat
results from there being more cells. A normal byproduct of metabolism in cells
is heat production. Subsequently, the more cells an animal has, the more
internal heat it will produce. Bergmann's rule is now an ecogeographical rule simply stating that within a
broadly distributed taxonomic clade, populations and species of larger size are found in colder
environments, and species of smaller size are found in warmer regions.
Exhibit Example: Comparative study of White Tailed Deer across the North Americas.
Ontario, Canada
300 pounds (180 kg)
50 inches (130 cm) at the shoulder
Large size helps this deer survive in the snowy North. A bigger deer has far
more heat generating muscle mass, but only a little more heat-losing skin
surface.
Missouri
250 pounds (110 kg)
40 inches (100 cm) at the shoulder
Florida Keys
75 pounds (35 kg)
30 inches (75 cm) at the shoulder
In the Florida Keys, even a full-grown deer is very small. With more surface
area per pound, it can easily dissipate enough heat to stay active without
overheating.
Fur
In order to survive the subfreezing temperatures, the artic hares are built with fur that slows the escape
of heat. The arctic hare lives in the harsh environment of the North American
tundra. These hares do not hibernate, but survive the dangerous cold with a
number of behavioral and physiological adaptations. They sport thick fur and
enjoy a low surface area to volume ratio that conserves body heat, most
evident in their shortened ears. These hares sometimes dig shelters in snow
and huddle together to share warmth.
Hares are a bit larger than rabbits, and they typically have taller hind legs and longer ears. Like other
hares and rabbits, Arctic hares are fast and can bound at speeds of up to 40 miles an hour. In winter,
they sport a brilliant white coat that provides excellent camouflage in the land of ice and snow. Beneath
its long, silky topcoat, its short, thick undercoat traps air between the hairs. The more air that it traps,
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the better it insulates. In spring, the hare's colors change to blue-gray in approximation of local rocks
and vegetation.
Feathers
Eider ducks live along the Arctic coast they are famous for their soft, fluffy
down feathers prized as insulation in bedding and clothing. Eider ducks
nest on tundra-covered islands in the arctic, so it is not surprising that they
have developed the warmest known down. And their outer layer of large,
stiff flight feathers “zip” together with tiny hooks to help lock in heat.
Blubber
Beluga whales inhabit the extreme environment of Arctic and
sub-Arctic waters and over time have evolved a number of body
adaptations to help them cope in such a cold and unwelcoming
place. Beluga whales have the thickest blubber of any mammal.
It is up to six inches thick. This layer of fat acts a barrier that
keeps heat from the whale’s muscles from escaping out through
its skin. Blubber is a thick layer of fat and fibrous connective
tissue that lies just below the skin of most marine mammals. A
beluga whale's circulatory system adjusts to conserve or dissipate body heat and maintain body
temperature. Blubber is vital to mammals in water, where heat is lost much faster than in air.
Chapter Two: Built to Move
Grabbing a Bite: Jaws and Claws
Everything has to eat. But food can be scarce and competition, fierce. How do animals use their inner
machines, muscles, levers and linkages to grab on and take a bite? In order for each individual to
survive, living things must create enough force to make an impact. With each grasp, bite, jump, or dash
organisms become a potent force upon the world, ready to take action and explore. Muscles set internal
machinery in motion, and joints become levers that enhance the power and speed of a grip or bite.
Discover the intense grip of a chimpanzee, and the tremendous strength of the Harpy Eagle (strong
enough to grab and carry off monkeys!). This section also introduces the incredible psychedelic-looking
Mantis Shrimp. This shrimp is an extremely hard hitter, thanks to its spring mechanism, allowing it to
crack open clams, crabs, and more. Amazing super slow motion video in the exhibition will show this
spring mechanism in action.
Visitors can also discover the force behind a bite. Some bites are harder than others because of the
shape of the skull and jaw muscles. Short, thick jaws (like a human or a T. rex) bite hard, whereas long,
slender jaws (like a dolphin or a stork) bite fast. Cases filled with different skulls will allow visitors to see
the differences between these different bites.
Jaws
Muscles drive the motion, joints act as levers, and hungry creatures capture their prey.
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Hard bite vs Fast Bite
Hard biters:
The height of the jaw is deep.
The length of the jaw is short front-to-back.
Lots of leverage to crush, but low speed.
Most of the muscle’s force is directly applied at
the bite point.
Fast biters:
The height of the jaw is shallow.
The length of the jaw is long.
Little leverage to crush, but high speed.
Corresponding Animals:
Megalodon (extinct) 40,000 psi
Saltwater Crocodile 29,000 psi
Piranha 26,000 psi
Dunkleosteus (extinct) 22,000 psi
T. rex (extinct) 12,500 psi
American Alligator 19,000 psi
Nile Crocodile 14,000 psi
Hippopotamus 3,000 psi
Jaguar 2,000 psi
Hyena 1,100 psi
Macaw 375 psi
Human 200 psi
Corresponding Animals:
The Wood Stork
Gharial
Longnose Gar
Dolphin
The force of the muscle is divided, but the speed
is multiplied.
Claws
Stone Crabs
Stone crabs prefer bottoms of bays, oyster reefs and rock jetties where
they can burrow or find refuge from predators. Juveniles do not usually
dig burrows, but instead hide among rocks or in seagrass beds. Stone
crabs feed on oysters, small mollusks, polychaete worms and other
crustaceans. The larger of the two claws is called the "crusher claw." The
smaller claw is called the "pincer claw." If the larger crusher claw is on
the right side of the crab's body, the crab is "right handed." If the
crusher claw is on the left side of the crab's body, it is "left handed." Since crabs' eyes are on stalks, they
can see 360°
How can a claw pinch so hard?
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A very strong muscle with diagonal fibers attaches to the moveable pincer.
The distance from the pull-point to the pivot point makes a difference. The in-lever is almost as
long as the distance from the pivot point to the crunch point, the out-lever.
When the muscle pulls back, the claw pivots close.
Most of the force of the powerful muscle is transmitted directly to the grip.
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Harpy Eagle
A harpy eagle can use its claws to hold tightly onto prey as large as itself. They have even been spotted
carrying off large monkeys plucked from the forest canopy. The bird’s muscles and joints create a force
at the base of the talon. That force is spread across the area where it
presses into its prey. If the force stays the same, but the area it is spread
across gets smaller, the pressure goes up. The smaller and sharper the
point, the greater the pressure at the tip. Talons concentrate all the force
of the leg muscles onto a handful of high-pressure points.
Crossing the Landscape: Legs and Springs
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. Creatures across the Earth skitter, hop, and run across the landscape on six legs,
ten legs, four legs, 100 legs, and sometimes just two. Despite gravity pulling down with each step,
springs and momentum redirect this force to the creature’s advantage.
Many people know that the cheetah is the fastest land mammal but
why is it able to run so quickly? This creature actually has a spine with
some extra spring to it, allowing the cheetah to take longer strides
which make it fast. Watch a video of a cheetah running in slow
motion to see this spring in action. A taxidermy cheetah from the
Field Museum’s collections will be on display mid-step to see the
curve of the cheetah’s “springy spine” up close.
The exhibition also highlights Mabel, a bipedal robot developed at the University of Michigan that
mimics the way humans walk. Human gait is difficult to reproduce because of our Achilles tendon which
releases energy like as spring as we walk. Mabel walks upright, and can even recover from a stumble.
The Cheetah
The Cheetah can go from 0 to 60 mph in three seconds with
three strides. Aerodynamics and a lightweight frame enable
its acceleration. Weighing at only about 125 pounds, its
muscles don’t have to carry much weight, translating into
acceleration instead. Its small head and flattened rib cage
and slender legs minimize air resistance.
Once in top speed, its unique design features sustain its speed. Its extremely flexible spine as well as
pivoting hips and shoulder blades are not attached to the collar bone. This allows the front and rear legs
to extend further apart and fully extend and move closer together when the feet come under its body.
This increases the cheetahs stride length. Its feet actually spend more time in the air than on the
ground. And its tail acts as a stabilizing runner in full speed. Even its feet are modified for speed. Unlike
other cats, cheetahs paws are hard and flat like tire treads and their front claws do not retract
completely like lions and leopards making them grip the ground like the cleats in a track shoe. These
modifications increase the cheetah’s traction and allows it to make short sharp turns.
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Land walkers
Salamanders
Like the first walkers on land about 400 million years ago, this modern
amphibian drags its belly and wriggles across the ground with its legs out to
the sides.
Iguanas
With its knees also out to the side but its belly off the ground, a reptile can
push off and run with less spinal bending than its 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, from walk to trot to gallop.
Wings and Fins
Only a small fraction of the earth is dry land. Over millions of years living
things have adapted to dizzying heights of the open skies and the crushing pressure of the deepest seas.
How do creatures manage to propel themselves through air and water? From walking on land to flying
through the air or swimming through the sea, animals have evolved the best ways to move for their
exact needs. With sleek aerodynamic forms, they harness the power of fluid dynamics to propel
themselves to their destination.
This section will give visitors the chance to “fly,” with an interactive designed to show the differences
between long and short wings. While it’s easy to get started flying with a short wing, it’s hard to
maintain flight. Long wings take more effort to get going, but flight is easier to maintain. These
differences affect the bird’s flight as well as their search for food.
In the sea, creatures move through the water using their fins and a fish must balance speed and
maneuverability as it swims. Some fish swim “from the tail,” which is stable, fast, but hard to turn.
Others swim “from the fins” which is very maneuverable, but slower and less energy efficient.
Wings and Flight
Flight evolved separately for four different types of animals: Insects, pterosaurs, birds and bats.
Scientists agree that wings must have
evolved first. They were used by the
ancestor for one function, and then
must have become useful for flight by
descendants. Wings could have evolved
to help capture small prey, to assist in
leaping, as a display to entice a mate, or
as gliding structures.
Birds
The earliest bird is Archeopteryx, who
lived 150 mya. Birds evolved in the
Jurassic period from a dinosaur
ancestor. The most obvious adaptation
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to flight is the wing, but because flight is so energetically demanding birds have evolved several other
adaptations to improve efficiency when flying. Birds' bodies are streamlined to help overcome air
resistance. Also, the bird skeleton is hollow to reduce weight, and many unnecessary bones have been
lost (such as the bony tail of the early bird Archaeopteryx), along with the toothed jaw of early birds,
which has been replaced with a lightweight beak. Bird wings are based on elongated forearm bones,
with short upper-arm bones. Birds also have a keeled breastbone, and a fused clavicle which support the
muscles and motions needed to flap wings. Modern birds live in every type of habitat, come in an array
of shapes and sizes, and have wing shapes suited to their style of flight. Some no longer fly, like penguins
or ostriches.
LARGE, STUBBY WINGS
This wing is almost twice as long as it is wide.
Slow
Birds with this wing shape are large but
lightweight, so they don’t need to fly fast to stay
aloft.
Soars
Birds with wings this large aren’t limited to
flapping. They can also soar, which saves energy
while hunting.
Example: Red-tailed Hawk wing
LARGE, SLENDER WINGS
This wing is six times as long as it is wide.
Fast
Birds with this wing shape are the heaviest fliers
alive. They need to fly fast to stay aloft—50 miles
per hour (80 km/h).
Soars
Birds with wings this large almost never need to
flap. Soaring saves them energy for long-distance
flights.
Example: Black-footed Albatross wing
SMALL, STUBBY WINGS
This wing is about as long as it is wide.
Slow
Birds with this wing shape are very lightweight.
They can fly quite slowly and still stay aloft.
Flaps
Birds with wings this small must flap, which is
tiring, but their small size helps them maneuver
through trees.
Example: American Robin wing
SMALL, SLENDER WINGS
This wing is three times as long as it is wide.
Fast
Birds with this wing shape are muscular and
heavy. They have to fly fast to stay aloft.
Flaps
Birds with wings this small have to flap, which
takes a lot of energy. They must rest often when
migrating long distances.
Example: Mallard wing
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Insects
Insects have been cruising the skies above Earth since the Carboniferous period, 320 mya. Fossils of
transitional forms are scarce, but scientists theorize that wings evolved from exoskeleton protrusions,
external gills, or possibly from body parts that originally served to regulate body temperature. The
earliest insect fliers had four wings like dragonflies. Now there are estimated to be over a million species
of insects, and they are among the fastest and most maneuverable fliers on the planet.
Fins and Fluid Movement
Marlins
Marlins swim slowly 99% of the time. But when they’re chasing lunch, they reach speeds of 60 miles per
hour. That’s the speed it takes to catch up to their prey, whack it with their nose, and swallow it whole.
They have a streamlined body shape, which reduces drag. Their fins fold flat at high speeds to become
as streamlined as possible. Once in motion, their weight—650 pounds—helps them stay in motion. Their
tail shape reduces drag too, increasing their speed.
Chapter 3: Built to Discover
Eyes are among evolution’s elegant gadgets. Look into how yours are an engineering marvel and then go
beyond the five familiar senses to explore “seeing” devices that need no light, teeth that detect earth’s
magnetic field and antennae that smell.
The world can be mysterious, but to survive, organisms need to decode the mystery of what is beyond
themselves. What is around the bend, food or foe? We collect clues with astonishing detection devices,
the senses. See how plants and animals decode the world beyond themselves with heightened sensory
equipment, some that detect forces we can only imagine.
See the asymmetry of a Northern Saw-whet Owl’s ear openings; the difference in the height of the ear
holes allow these hunters to hear more precisely, perfect for pinpointing the location of its prey in the
nighttime.
Another creature visitors will encounter is the Luna Moth, with its extra-large antennae. The Luna Moth
can smell farther than any other animal on earth, thanks to these antennae. The male can actually smell
a single molecule from a female from seven miles away. With only a week to live and find a mate, this
ability is key to the species’ survival.
Most people know that bats use echolocation to navigate; now humans are using echolocation to create
tools for the blind. The “UltraCane” sends out vibrations when it senses oncoming objects both on the
ground and in the air (rather than a regular cane, which runs into objects on the ground).
Venus Fly Traps
Biomechanics of morphing structures in the Venus flytrap have
attracted the attention of scientists during the last 140 years. The
trap closes in a tenth of a second if a prey touches a trigger hair
twice. Venus Fly Traps secrete a sweet nectar to attract their next
meal. With no brain, they rely only on a handful of sensitive hairs
to judge what they’ve caught.
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How does it know when to close?
1. If a trigger hair is only bent once, the trap won’t close. But that contact sets off a timer.
2. If two hairs are bent within the same period of time, an insect just might be walking around
so the trap snaps closed. An electrical impulse is triggered and the leaves snap shut like
prison bars. Now something is trapped inside. If “the thing” doesn’t thrash, the trap will
reopen. There’s no use in digesting a stick.
3. But if “the thing” continues to bend more hairs, then it must be alive. Now the trap can
confidently seal up its sides and digest. In about ten days the plant reopens and all that
remains is a desiccated corpse.
Echolocation
Echolocation also called bio sonar, is the biological sonar used by several kinds of animals.
Echolocating animals emit calls out to the environment and listen to the echoes of those calls that
return from various objects near them. They use these echoes to locate and identify the objects and
their surroundings. Echolocation is mainly used for navigation and foraging.
Bats
Bats use echolocation to navigate and forage, often in total
darkness. They generally emerge from their roosts in caves,
attics, or trees at dusk and hunt for insects into the night.
Their use of echolocation allows them to occupy a niche
where there are often many insects (that come out at night
since there are fewer predators then), less competition for
food, and fewer species that may prey on the bats
themselves. Microbats generate ultrasound chirps via the
larynx and emit the sound through the open mouth. To echolocate, bats call out in a pitch. This pitch is
not audible to insects. When an echo bounces back, the bat knows something is there.
Toothed Whales
Biosonar is valuable to toothed whales (suborder Odontoceti), including dolphins, porpoises, river
dolphins, killer whales and sperm whales, because they live in an underwater habitat that has favorable
acoustic characteristics and where vision is extremely limited in range due to absorption or turbidity.
The Sperm Whale’s Echolocation
Clicks for echolocation produced
by the nasal sacs are first sent back
through the mass of spermaceti,
reflected on an air sac in front of
the skull and only then directed
outward into the water through
another waxy substance called the
“junk.” This complex structure,
which has been fully investigated
only in the last 15 years, allows the
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sperm whale to create the most powerful and most directional clicks, reaching over ranges of hundreds
of meters to tens of kilometers.
Dolphin’s echolocation
Each of the two inner ears is isolated acoustically from the other, enabling the dolphin to precisely
locate the sources of underwater sound. Hearing is remarkably acute throughout a broad range of
frequencies, and the dolphin is capable of distinguishing small differences in the frequency (pitch) of
sounds. One of the types of sounds produced by dolphins is the whistle, a narrow band continuous
sound that varies in its frequency. Individual dolphins tend to have unique whistle sounds, called
“signatures,” and can be easily recognized by other members of its group.
Additionally, the inner ear has been modified to allow for the perception of high-frequency sounds,
reaching some ten times or more above the upper limit of adult human hearing. The ability to sense
these high-frequency sounds is vital for the dolphin’s echolocation sense and allows the dolphin to
detect very small objects. A series of very short duration, high-intensity, broad-band clicks containing
frequencies as high as 120-kHz are projected in a narrow beam from the region of the dolphin’s melon
and broadcast in front of the dolphin into the adjoining waters. When the clicks strike an object, echoes
are returned and sensed by the dolphin through its special pathways for hearing.
Recent research suggests that these echoes may preserve the spatial structure or shape of the reflecting
object and be interpreted by the higher center of the dolphin’s brain as an image of the object. This
echolocation sense seems to be closely integrated with the dolphin’s visual sense, allowing it to easily
relate things heard to things seen.
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Magnetoreception
Magnetoreception is a sense which allows an organism to detect a magnetic field to perceive direction,
altitude or location. This sensory modality is used by a range of animals for orientation and navigation,
and as a method for animals to develop regional maps.
Sea Turtles
From the very first moments of life, hatchling sea turtles have an arduous task. They must embark on a
transoceanic migration using incredible powers of navigation. It
appears that the turtles pick up on magnetic signatures that
vary across Earth's surface in order to determine their position
in space—both east-west and north-south—and steer
themselves in the right direction. Earth's magnetic field, which
acts as a giant invisible shield that protects the planet from
dangerous solar radiation, changes over time. Earth's iron core
is surrounded by a layer of molten metal, and as this molten
metal sloshes around, it causes fluctuations in the magnetic
field, with some areas strengthening and others weakening.
It's possible that tiny magnetic particles, or magnetite, in their brains help the turtle’s process unique
signatures. Magnetite was also used by sailors in the earliest compasses.
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Luna Moth
Certain types of moth have an olfactory sensitivity that verges on the supernatural. They can detect a
single molecule of the female sex hormone from miles away. Males of the saturniid, bombycid, and
lasiocampid families of moth, which include luna, emperor,
polyphemus, vaporer, and silk moths, have large, feathery antennae
that bear the moths' hair like olfactory receptors in great quantities (as
many as 60,000 in some species).
Thanks to their broad shape, the antennae come into contact with the
largest possible volume of air, making them perfect scent receivers.
The females of some moths produce an odor that the males can detect
with large feathery antennae. So sensitive are these organs and so
characteristic and powerful is the scent, that a female has been known
to summon a male from ten kilometers away! At such a distance there
must be as little as one molecule of scent in a cubic yard of air, yet it is
sufficient to cause the male to fly in pursuit of its source. A female emperor moth, in a cage in a wood,
transmitting a perfume undetectable to our nostrils, has attracted over a hundred huge males from the
surrounding countryside within three hours.
Sue
No one was able to film T. rex in action, but we have the next best thing. Visitors will be able to check
out digital reconstructions of Sue’s locomotion frame-by-frame, or at top speed. And they’ll see why
scientists have come to the conclusion that Sue’s top speed maxed out at only 18 mph, more of a speed
walk than a sprint.
Bite
Sue’s bite was one of the strongest on Earth. When scientists calculated the forces of all her muscles
working together to bite down, the highest “readings” showed a force of 12,500 lbs. And those jaws
were full of teeth affectionately referred to as “lethal bananas.” Visitors will be able to feel how their
shape allowed her to rip through flesh and bone without them breaking off—most of the time. How do
we know how hard Sue could bite?
First, scientists scanned a T. rex skull to create a digital 3D model. Then, they digitally attached all the
major biting muscles, each with an assigned strength. A computer program calculated the forces from all
the muscles working together to bite down. The highest “readings” showed a force of up to 40,000
Newtons (12,500 lbs). In terms of pressure, one tooth may have reached 21,000 pounds per inch.
Eyes
With eyeballs larger than softballs, a T. rex could see up to 13 times more sharply than we can in
daylight. Visitors will see how the optics of an eye that immense combined with forward positioning to
give Sue a sense of vision fit for a predator. Sue’s eyeballs were about 3 ½ to 4 ½ inches across, a little
larger than a softball. An eye that large could let in more moonlight for better night vision. And because
dinosaurs are related to birds and crocodylians, it’s likely Sue also had sophisticated color vision. Sue’s
eyes faced forward with 55 degrees of overlap between left and right eyes similar to modern hawks.
This allowed her to see in 3-D and judge the distance to her prey even when it stood still. In contrast,
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most snakes have less than 20 degrees of vision overlap and can only distinguish their prey from the
background if it moves.
Movement
How do scientists estimate how fast T. rex could move? First they scan the bones into a computer
program and attach digital muscles. Then for every posture with plausible joint angles, they calculate the
strength needed to push against the ground mid-stride. The highest “readings” come out to around 1.5
to 1.87 times body weight. Working backwards from these numbers, they can estimate the animal’s
speed.
Teeth
When scientists made casts of a few of the eighty bite marks found on one Triceratops pelvis, the results
looked suspiciously similar to a T. rex tooth (left). With sixty thick, serrated teeth scientists nicknamed
“lethal bananas,” T. rex could easily bite through flesh and bone. All of Sue’s teeth have two serrated
edges for cutting, but where you find them depends on the tooth’s position in the mouth. Side teeth,
like this one, have serrations on the front and back edges, while front teeth have both serrations toward
the back of the mouth.
Sue is the world’s largest and most complete T. rex. Although she lived 67 million years ago, we can
recreate the way she moved, fed, and saw the world—using biomechanics.
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