By Linda O'Connor
Photo by John Ingraham
Are you tired?
A few weeks ago, most Americans reset clocks to spring forward for Daylight Savings Time. You might have found yourself yawning as your internal clock reset itself.
The time change probably didn’t affect your dog or cat or other animals, but that’s because animals’ internal clocks are in tune with their environments and the rising and setting sun.
Some animals wake at dawn. They’re active during the day and sleep at night. These animals are called diurnal--and humans are the best example of diurnal activity.
Animals that are awake and most active at night are called nocturnal. Porcupines, bats, owls, opossums are good examples.
Deer are crepuscular, meaning active in twilight hours. Photo courtesy USFWS
Still other animals are crepuscular and are most active at the twilight hours of dusk and dawn. Deer, for example, are crepuscular, and so are most deer family members such as moose or elk. Other crepuscular animals are rodents like hamsters or mice and rats, and some insects, snakes, rabbits and brown bears.
Despite the natural rhythms of nocturnal and crepuscular animals, scientists have learned human activity can disrupt sleep patterns for animals as well as interrupt hunting for food.
One of the interesting things about the word crepuscular is that it is also a type of ray seen at twilight when the sun goes down.
Here are some links to information about crepuscular animals and light rays.