Vision: A Resource for Writers
Lazette Gifford, Editor

Creature Building 101:  Part 4

By Marilyn Glazar
2004, Marilyn Glazar

Part 1

Part 2

If you are following along and making up a creature, you have a pretty complete idea of its lifestyle by now.  You've had to make decisions about how it interacts with its environment, other types of creatures, and creatures just like it.  You probably even have a pretty good idea of what it looks like.  In this last part of the creature building workshop we're going to focus on appearances.  This may seem like a superficial subject, but it builds on everything we've talked about so far and adds a few new angles to an already complex subject.

The subject of the first article was survival.  In that article, creatures were placed in their environments and had to deal with the inherent dangers there.  A desert creature may be nocturnal and navigate by sound or may have scaly skin that seals in moisture.  An arctic creature may have thick fur.  Creatures that are hunted may have camouflage or a means of quick escape such as flight.

In the second article, creatures had to find sustenance.  The problems of predators, parasites, and mutualists were investigated and creatures developed relationships with other creatures and plants in their environments.  A predator needs a means of capturing its prey.  This could mean speed, claws, teeth, or even a lure.  A parasite needs a vector, or a way to get into its host, and it needs to generally be smaller than its host.  A mutualist has to be able to meet the needs of its partner perfectly and will have an appearance that helps it do that.

Finally, in the third article, creatures' personal lives were laid bare to the public.  Some of them have sex and some of them don't.  This is important to appearances because creatures that have sex have to be able to identify each other.  Not only do they have to know what the opposite sex of their species looks, smells, or feels like, but they also have to decide which mates are worthy and which are not.  Some creatures will have antlers, brightly colored plumage or fur, or unique and interesting structures just for this.  In fact, some creatures have special appendages just for the exchange of genetic material.

If that isn't enough, there are even more things to consider about a creature's appearance than its general lifestyle.  How big is it?  What's its general body plan?  How does it move from place to place?  And, most importantly, does it have lips?

In questions of size, it makes a big difference whether the creature has to be scientifically plausible.  Even there, there is some leeway.  Arguably, no creature in fiction has to be entirely scientifically plausible.  There is almost always room for doubt.  Scientific plausibility and fictional believability are two different things.  Still, in looking at creatures on this planet, there seem to be some limits for size in either direction.  These limits are placed mostly on certain body types.  Each type has its own limitations.

First, consider the blob.  The vaguely spherical jelly filled shape of single-celled creatures only gets to be so big.  This type of creature doesn't have a digestive system.  It takes in its food by surrounding it with its outer covering or, more often, simply absorbing it.  It gets rid of waste material by doing the same things in reverse.  It can move its insides around but there is no organized circulatory system.  While it has a great deal of mobility, it doesn't have a muscular system and outside of a mostly liquid environment it can't move from place to place very easily.  Besides, it would dry out and die quickly.

The reason the blob is so limited in its size is because of something called the surface to volume ratio.  The larger a blob gets the less surface area there is when compared to the amount to stuff it carries around inside it.  Taking in enough food to sustain it and getting rid of enough waste to keep it alive become problems.  That's why most very simple blob shaped creatures, like amoeba, are microscopic.

Humans have size limits, too.  The man billed as the tallest person who ever lived is Robert Pershing Wadlow.  He was eight feet, eleven and a half inches tall at the time of his death.  The world's shortest woman, Madge Bester, is about twenty-six inches tall.  Robert's pituitary gland produced too much growth hormone and, though he was reportedly healthy, he did have a few difficulties associated with his abnormal height.  Madge Bester has a disease called osteogenesis imperfecta and this makes her bones extremely fragile.  There was a shorter person even than her; however, little is know about Lucia Zarate aside from the fact that she was about seventeen inches tall at the age of twenty.  These remarkable cases exhibit the flexibility of the human form but also show that there are limits.  Such limits in size exist in every type of organism, but variation to some degree is the norm.

The smallest creatures are bacteria, so tiny that even a light microscope only shows them as specks of various shapes.  Smaller than bacteria are viruses, which are sort of on the border between living and not living and can only be seen using an electron microscope.  The largest creatures that ever lived, as far as we know, are blue whales.  However big your creature is, it has to have the machinery to help it survive at that size.  Bacteria are simple creatures.  Whales are not.

After size, the next question is one of shape.  Most creatures exhibit some form of symmetry.  Symmetry is balance.  Creatures very rarely look as though they were put together randomly, but they are not all built from the same blueprint.  Most of the well known creatures on this planet exhibit a kind of balance known as bilateral symmetry.  If you made an outline of the basic shape of one of these creatures you could fold it in half down the middle and everything would match up.

People are bilaterally symmetrical.  We have two arms, two legs, two nostrils, two eyes, and two ears.  Each one of these pairs is located on the opposite side of the body from the other.  People do have one each of a few body parts.  We have one nose, one mouth, and one navel.  Each of these is located at the centerline of the body.

In planning a bilaterally symmetrical creature, it is important to remember that all features will come either singly at the centerline of the body, or in even numbers on opposite sides of the body.  A creature like this can have twelve legs, but it isn't likely to have three.  This rule could be broken if the odd numbered feature were located at the centerline.

Another way to plan a creatures shape is to use radial symmetry.  These types of creatures are often found in aquatic environments.  Their outlines could be folded in more than one way and still match up on each side.  The folds have to go through the center.  Think of a squid or a sea anemone.

Now that the creature has a basic body plan it needs a way to get around.  Not all creatures bother getting around much; some are rooted at their bases like plants and others are just not incredibly mobile.  For instance, a mussel has a single muscular foot that helps it dig into the sediment, but it doesn't exactly walk around the seafloor.

If a creature has a skeleton in conjunction with a muscular system and legs, it can probably walk.  Remember that skeletons come in inner and outer varieties (humans vs. insects).  A lot of creatures on this planet get around by walking.  If it doesn't walk on legs, it might extend and contract itself like an earthworm or move in a zigzag undulating fashion like a snake.  If it's an aquatic creature, it can move with a side-to-side motion or paddle its way along with finlike structures.  Flight is a specialized method of locomotion and the creatures suited to it have to be at least somewhat aerodynamic.  The wings also have to provide more lift than the drag created by the creature's body weight and friction.  Whatever its method of locomotion, a creature has to be well adapted to it.  Extra appendages are not usually stuck on without a reason for them being there.

That brings us to the very important question of lips.  We use lips for a lot of things.  We use them in eating and talking.  We paint them to help attract mates.  We smile and frown with them.  However, as useful as we find lips, they were originally (as far as we know) not designed for any of the above.  Chickens do not have lips.  Neither do fish or lizards or frogs or even birds.   However, dogs have lips, as do monkeys, kangaroos and camels.

Notice a pattern?  Only mammals have lips.  Lips were designed to operate the nipple of the mammary gland in mammals so that infants could be nourished.  It isn't necessary to give a fictional lizard-creature all of the attributes of earth lizards, but if you give it lips, there has to be a reason. 

The point here is to think carefully about the effects of a structure before giving it to your creature.  This goes for all structures, especially those that are normally thought to belong with a different type of organism then the one being created.  When sticking them on a fictional creature, the author would do well to consider their reason for being there.  The consequences could affect everything from mating and child rearing to basic survival.

If you've been following along with creature creation you should now be ready to work your new creature into your story line.  Hopefully, your strange new creature has helped you to create a world that has more depth and believability.  Earth would certainly be poorer if not for all of the strange and diverse creatures that roam around on it.

Additional Information:

Web Sites:

This is a friendly, short biography of Robert Pershing Wadlow, the world's tallest man.

This is a news article about the world's shortest man and woman and their campaign to help the disabled.

This page gives some basic information about osteogenesis imperfecta.

Here is some interesting historical information about how very short people were once treated and a vintage photograph.  It is a British site that is trying to sell the photograph.

Here you will find everything you might want to know about snakes.

This site is geared toward kids but is chock full of all kinds of information.  This particular page talks about dinosaurs and has a link to some information about blue whales.