Preparing for Winter – How Do They Know?

The ability of plants and animals to achieve maximum survival success in changing seasons is quite interesting. Here in Michigan, our winters can arrive suddenly and forcefully. It may be 75 degrees one day and below freezing the next. It was quite warm in early September, but many trees were already preparing for winter. The leaves of our sumac trees became brilliant red and started falling off the branches. As we approach the end of September, some species of maple trees are changing colors and dropping their leaves.

Several species of birds have left Michigan, heading south for the winter. We live on a river where we see a massive increase in fish activity. There is also a significant increase in the activity of insects, with some butterflies, such as monarchs, heading south in groups. The number of cocoons in our bushes and in our house has accelerated, and some species of bees and wasps have become more aggressive.

The big question is how living things seem to know it’s time to start preparing for winter, even when there is no significant temperature change. There have also been no clues from other weather factors like humidity, rainfall, wind velocity, and direction. The scientific evidence shows that living things pick up on less obvious signals that say, “Winter is coming, and you need to prepare.”

Some living things sense the length of daylight, telling them to prepare for winter. Another factor is the angle of the Sun’s rays, which controls what kind of light reaches Earth’s surface. The Sun’s light contains a variety of wavelengths. The higher energy wavelengths are refracted and scattered more than the longer, lower energy forms. The sky is blue because blue light has higher energy than the rest of the visible spectrum and thus is scattered and refracted more. The next highest energy wavelength is green. Plants are green because they reflect that color, protecting them from the next highest energy of light that reaches Earth’s surface.

As the Sun gets lower in the sky, wavelengths we can’t even see, such as ultraviolet, are refracted and scattered away from the surface. Living things detect that change and start preparation for winter. Explaining how this system of life came into existence is a real challenge for those who deny God’s creation of our planet and the life on it. It’s a joy to see the things God has made testifying about His intelligence and design as they start preparing for winter (Romans 1:20).

— John N. Clayton © 2023