This past Sunday at 2 a.m., our clocks were changed back to standard time. This hour change sometimes throws me for a loop and takes me a while to become accustomed to.

Have you ever wondered if the change of time affects wildlife? The answer is no since most animals live on the same rhythm as humans. The two rhythms that humans and most animals follow are the seasons and day and night. However, there is a third rhythm that some animals follow.

According to the book “Animal Timekeepers” by Navin Sullivan, the rhythms of day and night are caused by the rotating Earth. Of course, the Earth rotates approximately 365 times a year, while making this journey around the sun. As we travel around the sun, the Earth tilts on its axis, and this is what gives us our four seasons.

During these four seasons the animals breed, raise their young, go through the breakup of families and prepare for the winter season by either migrating, hibernating or putting on extra fat and heavier coats. All changes are due to the rhythm.

The third rhythm that is important to some creatures is the rhythm of the tides. These tides are caused by the pull of the moon. As the Earth rotates, the tides are carried to each shore in turn. Because of the monthly travel of the moon around the Earth — every 27 1/2 days — it is overhead at a particular place on Earth 50 minutes later each day. As a result, the tides come 50 minutes later each day. There are high and low tides approximately every 12 1/2 hours.

Some creatures living in and along the seas and oceans live according to this rhythm of the tides. If you were to take a walk on the beach during low tide, many barnacles would be found uncovered on the sandy beach. At low tide, sandpipers and fiddler crabs also appear on the sandy beaches in search of food, however the barnacles aren’t available to them because they have sealed themselves tight, and it is almost impossible to pry a barnacle open.

Later, at high tide when the barnacles are covered with water, the shells will have opened for feeding time.

The fiddler crab changes color according to the time of day. In the morning, it has silvery gray skin, but as the day goes on, the fiddler crab’s skin begins to darken. At noon, the skin is at its darkest and then begins to lighten until sunset when it is silvery gray once again. Some people living along the shore can tell the time of day by the color of the fiddler crab. Scientists believe the dark skin protects the crab from the sun’s hot rays.

One might think that this change in color occurs because of the sun, but in a study done on fiddler crabs that were taken from the beach and put in a completely darkened room, they continued to change colors according to the schedule followed on the beach. Scientists believe that fiddler crabs have an inner clock, which keeps them in step with the 24-hour clock.

Scientists placed fiddler crabs from Cape Cod, Massachusetts, into darkened containers, which were flown to Berkley, California, where day and night arrive over three hours later than on Cape Cod. Half of the crabs were kept in darkened containers, and the other half were put out on the beach.

The group in the containers continued the Cape Cod schedule while the crabs released on the beach experienced day and night and altered their schedule to keep time with the west coast. Both groups had reset their internal clocks.

In other studies, creatures such as bees, which had been taken to new locations, reset their clocks according to daylight. The 13- and 17-year cicadas have an internal clock, which causes them to appear after spending years underground.

After many years an internal clock brings the salmon back to their birthplace to spawn.

We humans also have an inner clock and even a one-hour change will be noticed. Those who travel great distances are said to have jet lag until they re-set their inner clocks.

Light and darkness and the seasons govern the lives of animals by day and by year. Some are sent on long journeys, others go into deep sleep, while others put on heavy coats and extra body fat. They are acting according to their internal clocks set by the Earth, moon and sun.

One of the most remarkable timekeepers is the grunion, a small fish that lives off the coast of Southern California. Twice every month — once on the full moon and once on the new moon — an extra high tide occurs. During these tides, the waves go farther up onto the beach than at any other time. The grunions ride the waves of these extra high tides and lay their eggs on the beach at the highest point reached by the water.

In 15 days, at the second extra high tide as the water reaches the eggs, they hatch, and the young fish swim away.

A sea worm that lives in the waters of the West Indies also has an accurate inner clock. Each October when the moon is just into the third quarter, the sea worms swarm on the surface of the Atlantic Ocean. The female worms give off a glowing light, which attracts the male.

On one of his journeys crossing the Atlantic Ocean, Christopher Columbus wrote in his journal (Oct. 11, 1492) that mysterious lights were seen on the ocean. From the date recorded, we now know that the lights were from the swarming female sea worms.

Humans also have inner clocks for such things as temperatures and elevations. It takes us several days to become accustomed to the cold, heat and different elevations.

It will probably take me a week before I am accustomed to the standard time. Hopefully Mary Alice’s inner clock will adjust quickly to standard time because not getting supper on time will throw off my internal clock.

Bill Bower is a retired Pennsylvania Game Commission Wildlife Officer. Read his blog and listen to his podcasts on the outdoors at www.onemaningreen.com.