Rocky the Rock Pocket Mouse
by Dr. Moore
Rocky the Rock Pocket Mouse wasn’t like the other mice in his habitat. Every
other Rock Pocket Mouse Rocky had ever met in his whole life was sandy in color,
like the desert floor. Rocky, however, was black.
“Why are you a different color from the rest of us?” his classmates would ask.
“Why are you a different color from your parents?”
“SHUT UP!” Rocky would say, but the truth was he didn’t know the answer.
One day he decided to ask his kind and intelligent biology teacher, Dr. Moar.
“Dr. Moar,” asked Rocky. “Why am I a different color from all the other Rock
Pocket Mice? Why am I a different color from my parents?”
“Oh, Rocky,” Dr. Moar said. “You are different color from your parents and all
the other mice because you have a mutation.”
“What’s a mutation?” asked Rocky.
“A mutation is a change in your DNA. It’s a mistake that occurs when the DNA
is being copied.”
“Why do I have a mutation?” asked Rocky.
“Mutations are just something that happens.” Dr. Moar explained gently.
“Am I the first mouse to have a mutation that turns me black?” asked Rocky.
“No,” said Dr. Moar. “One of my classmates had a mutation that made him
black, too.”
“Well, what happened to him?”
“Oh, he got eaten by a hawk before he had a chance to reproduce because he
didn’t blend in to the sandy desert floor.”
“Oh,” said Rocky, not feeling reassured.
The next morning, Rocky awoke to a mighty rumbling. The volcano on the far
side of the valley was erupting! He ran deep into his burrow to escape the lava.
When the lava had cooled, the valley where Rocky had lived his whole live
was completely unrecognizable. The ground was no longer sandy in color, but deep
black.
His light-colored classmates, who used to tease him about his dark color, now
stood out on the dark background. They were easily spotted by hawks, who would
swoop down and carry them off.
Rocky, on the other hand, matched his new environment perfectly. He grew
up to have many babies, many of whom were dark like him. His dark offspring, able
to hide on the dark rocks, grew up to have many babies of their own, and many of
those babies were dark, too. By the time Rocky died of old age, there were hundreds
of dark mice in the population, and he didn’t feel self-conscious about his mutation
any more.