Nocturnal creatures reveal themselves with colorful eyeshine
Since some of us drive country roads after dark, our travels may take us through many rural areas. This offers us the opportunity to observe, sometimes very briefly, several types of nocturnal creatures that you may not see often during the day.
Perhaps the most commonly sighted are white-tailed deer. Over the past couple of weeks, I have seen over a dozen including a couple of impressive size. While graceful, fast and agile on grass, mud and sand, deer, being hooved animals, seem to somewhat unsuredly tip-toe across hard surfaced roads. Probably one of the reasons many become fatalities in collisions with vehicles.
The eyeshine of nocturnally active animals has always fascinated me. Night active animals have eyes that are rich in rod cells. Nocturnal animals have a mirror-like membrane at the back of their eyes behind the retina that basically reflects light back through the eye. This layered membrane is called the tapetum.
The reflected light is basically unused light. Humans do not have this membrane. The “red eye” from a camera flash is the light reflecting off blood vessels and red tissue in our eyes.
The eyeshine of a deer is usually whitish.It can also appear light green or yellowish. Alligators have brilliant ruby-red eyeshine. If you find a pond, lake or swamp with a good population of alligators, shining a light across the surface will reveal several reddish eye shines dotting the surface. Bullfrogs fittingly have green eyeshine.
Bright yellow eyeshine usually belongs to a raccoon. Coyotes, wolves and dog’s eyes usually have a fiery white glow. A bobcat’s eyeshine is yellowish white. A bear’s eyes will glow fiery orange.
Night eyeshine is not only exhibited by some of the mammals, reptiles and amphibians. Wolf spiders have star-like glittering white eyeshine. Many moths exhibit an orange-red glow to their eyes. The same holds true for owls.
Humans have more cone cells in our eyes than the rod-rich nocturnal creatures. As a result, we give up good night vision but can detect many colors. Night active animals normally do not have acute color vision but can see very well in limited light conditions.
In the Tallahassee area, the Apalachicola National Forest and state parks are good places to cruise rural roads after dark. Remember to practice safe driving habits when looking for animal eyeshine during your adventure.
The next time you are outdoors at night, look for the eyeshine of our wild neighbors. It can be a fun and educational experience. A nocturnal detective game that can be enjoyed by young and old alike. Keep a list of critters and the color of their eyeshine that you observe.
Eyeshine Fact: armadillos are said to have no eyeshine.
Enjoy your North Florida nature trails.
Jerry is a Naturalist, Teacher and Nature Writer living in North Florida. For questions or comments, e-mail Jerry at firstname.lastname@example.org.