Like other animals, we thrive in sun
MY retreat from the marine world is ending. Though I haven't taken the plunge back into the ocean yet, I'm getting my feet wet during daily walks on Kailua Beach.
Usually I go in the early morning or late afternoon to avoid the midday heat, but last weekend I went at noon. It was fun being part of the huge holiday crowd. What I enjoyed most was watching people sunbathe.
That sounds like as much fun as watching the dog sleep, but the variety intrigued me. The baskers were large, small, young, old, white, brown, clothed and unclothed (pretty much), all lying spread-eagle in the sand under the glaring sun. Why, I wondered (besides wanting a tan), do so many people so love to bask?
WHILE I WAS a student at the University of Hawaii a long time ago, a professor of animal behavior told a good story about basking. While he was working at a Southwest University, someone brought an injured golden eagle to his lab. After treating the minor injury, the professor and his grad students made a tall perch for the bird to sit on while recovering. They also shined a heat lamp on the tired eagle for extra warmth.
As soon as the lamp went on, the bird surprised them all by opening its massive wings and holding them out. When the biologists turned the light off, the bird folded its wings. With the light back on, the bird opened its wings again. Light off, wings in. The eagle was basking in this artificial sun.
The professor's point was to teach us that in the animal kingdom, which includes us, basking behavior is both natural and widespread.
The reasons behind it, however, might be quite different. In the case of birds, researchers believe some basking is an attempt to get rid of parasites by exposing them to the sun. When cormorants do it, though, they're hanging their wings out to dry, since cormorant feathers aren't waterproof. And when reptiles lie in the sun, these cold-blooded animals are usually doing it to raise their body temperatures.
The human instinct to seek the sun also has a physiological basis. It is sun exposure that causes our skin to make vitamin D, an essential vitamin regulating calcium and phosphorus absorption in our bodies. Researchers theorize the first human settlers in Greenland died out from vitamin D deficiency due to lack of sun exposure.
ALSO, SINCE WE warm-blooded mammals must create our own heat to maintain a constant body temperature, absorbing the sun's heat conserves calories.
One enlightening discovery about our craving for sunshine is that it prevents a wintertime depression called seasonal affective disorder, or SAD. Sunlight stimulates the brain's pineal gland to produce chemicals called tryptomines, which improve our mood. The sun gets us high.
Another plus for basking could be, surprisingly, cancer prevention. Recent studies suggest sun exposure might reduce our risk of breast, colon, ovary, uterus, bladder, stomach and prostate cancer.
Overdo it, though, and it goes the other way, causing the deadly cancer melanoma. As usual, moderation is the key.
People have good reason to come all the way to Hawaii to lie on a beach in the sun: Like lizards, we are born to bask.