Creature Building 101:
In the last creature building article we
covered survival mechanisms. Most creatures have environmental difficulties to
overcome, and the methods that they use to overcome them are great for tying
them into your world. If these were the only problems that they had to overcome
then the job of making them up would be fairly simple. There are, however, a
few other problems that animals have to defeat in order to continue to exist.
Chief among these problems is the question of
how to obtain energy and water. Other forms of sustenance may also be
necessary. Salt, vitamins, and trace minerals can all send animals licking,
nibbling, and ingesting unlikely bits of their environment. The need for
sustenance is persistent and ever-present. Many animals spend every waking
moment foraging for food.
If that weren't problem enough, the energy
almost always has to come in a very specific form. A cow can't be fed pork
chops when the hay runs out and a vampire won't be satisfied with spring salad
mix and a nice vinaigrette. In fact, the vampire wouldn't take the pork chops
either, and the cow would be quite put off by the vinaigrette. Animals are very
specific about what they eat. They don't just eat meat or plants. They eat
grasses or small mammals, or human blood.
Knowing how your creature solves the problems
of its physical environment will help you figure out how it can solve its
sustenance difficulties. If it sleeps at night because its body temperature is
too low for much movement, it certainly won't go hunting then. If it has tough
protective scales or water-proof hide, it won't absorb anything very well
through its skin.
There are almost as many ways to solve the
problem of sustenance as there are animals. Animals on this planet almost
always obtain sustenance through a relationship with another type of living
thing. This means that when you are making up one creature, you almost always
have to make up another creature or plant for it to obtain sustenance from.
Most people know that herbivores eat plants and
carnivores eat other animals. These relationships are predator-prey
relationships. We tend to think of this in terms of one living thing dieing in
order for another living thing to survive. A wolf pack feeding on deer is
exhibiting this kind of relationship but so is a slug feeding on lettuce. It is
important to remember that predators must strike a balance in order to survive.
If they get too good at their job they might run out of prey and die of
starvation. For this reason there are always more prey organisms than there are
predators. You might see vast herds of antelope but you won't ever see that
many lions in one place.
Predation works, and it is the most common way
for a creature to get energy, but it isn't the only option. Again, lets look at
a couple of real-life examples and one from the fictional realm.
The canine heartworm gets all of its
sustenance, for most of its life span, from its immediate environment. It
spends most of its life in the bloodstream of a dog, and has every need catered
to quite nicely. As an adult it will move into the dog's heart or lungs where
it will reproduce, sending its many tiny offspring into the bloodstream where a
mosquito might carry them to another dog. If the parasite is lucky, the dog
will live for many years. Often though, the extra strain of carrying heartworms
around in the chambers of its heart will cause a dog to die. The heartworms, of
course, will die when the dog does.
Parasitism is a valid way for creatures to
solve their sustenance problems. If a source of nutrients isn't completely used
up at a feeding, but is allowed to continue growing and obtaining more
sustenance, then the parasite never has to go looking for food. A great many of
the parasite's survival problems can also be solved by living inside a host
where environmental problems won't bother it and predators can't get to it.
The parasites we know of don't take over their
host's nervous system, but the idea of a parasite taking over a human body and
mind is so gruesome that practically an entire subgenre of horror and science
fiction novels have dedicated themselves to it. My particular favorite is The
Puppet Masters by Robert A. Heinlein.
Another type of relationship that can solve a
creature's sustenance problems doesn't involve harm for either of the creatures
involved. An example of this relationship is found in between two animals in
Africa. There's a bird called the honey guide that just loves honey but can't
get to it alone. The honey badger likes bees and larvae and has thick skin and
fur to protect it from the bees' sting. To get fed, the bird only has to find a
bees' nest and lead the badger to it. The badger does the work of tearing the
nest apart and devouring the bees. When it's done the bird gets to eat its fill
of any leftover honey. Everybody wins. Well, everybody wins except the bees.
The badger and the bird have a mutualistic relationship. The bees are prey.
In the real world as we know it, creatures get
energy mostly by ingesting each other and plants. In the fiction this isn't
necessarily so. One example of this would be the case of the dementors that
figure highly in the plot of Harry Potter and the Prisoner of Azkaban.
Dementors don't eat. Instead, these creatures get their power by creating fear
in people and siphoning it off. It seems that they also have a hunger for human
souls that they can suck out of a person through the victim's mouth.
While dementors might seem to break some of the
rules that creatures on earth follow, they do follow the rules of preditor prey
relationships. Dementors are not always successful on the hunt. Humans can
defend themselves against dementors, if they know the patronus spell. It is
also important to note that there are a lot more humans than there are
dementors. If the dementors were invincible or if there were more of them than
there were people, then the creatures would not be believable. Monsters that
aren't believable aren't nearly as scary as those that seem real.
While it is important that creatures be
believable, it isn't necessary that they be predictable. Perhaps a creature
could obtain some or all of its sustenance from an environmental source such as
sunlight or radiation. Maybe a formerly parasitic relationship could be thrown
out of whack by circumstances and become more mutualistic. In fiction no rules
are absolute. They are merely guidelines to help the author make a story work
Sustenance relationships take place between
different types of organisms. In order for a creature to really come to life,
it will need to be able to reproduce itself and this almost always involves
relationship between it and other creatures just like it. In the next article
we will look at reproduction.
Book Mentioned: Puppet Masters by Robert
A. Heinlein. ISBN
Book Mentioned: Harry Potter and the
Prisoner of Azkaban by J. K. Rowling, Mary Grandpre (Illustrator). ISBN
If you find the idea of parasites intriguing
and want to learn more about them, you might enjoy reading
New Guinea Tapeworms and
Jewish Grandmothers: Tales of Parasites and People by Robert S.
Desowitz. ISBN: 0393304264
Web Sites of Interest
This site has pictures of parasites and
examples of life cycles.
This site has a lot of information about honey
badgers, including an argument against the widely used practice of calling its
relationship with the honey guide mutualism.
This is a look at some marine animal mutualism.