Wednesday, January 7, 2009

By the light of the moon

Photo credit: Andrew McMillan

My niece is working on a science project examining the effects -- real or imagined -- of the full moon on human behavior. I was poking around on the net, looking for some studies that might help her write up her background section, when I came across some interesting data about animals.

While the jury is still out about people -- it seems many think the moon affects human behavior but statistics don't seem to support this (although there have been some studies that do) -- a full moon has been shown to affect animal behavior.

As recently reported in Discovery Channel news, a new study to be published in the journal Animal Behavior has shown that a Full Moon Energizes Birds, at least in the case of the marine streaked shearwater.

A 2005 paper published in Wildlife Biology also documented an increase in noctural activity during the days surrounding the full moon in another bird, the yellow-throated marten.

And a 1974 study, reported in the journal Oikos, showed that the toad, Bufo americanus, was less active during a full moon.

From an ecological perspective, I think it makes sense that the moon would influence animals in predator/prey interactions, simply by increasing the amount of light available for the hunt. If you were a predatory bird, this would work in your favor and you might be more active. If you were a toad worried about being eaten, you'd stay put during a full moon.

Now, I'm less sure about dogs and cats. Like people, they've adapted to our lives full of artificial light, so the influence of light level from the moon seems like it would be less influential. But does the moon still exert an influence?

Maybe, maybe not.

In 2001, reported on two studies published in the British Medical Journal, one from England that showed a correlation between dog bites and the full moon, and one from Australia that did not (although if you look at the data, there appears to be something exerting an effect each month).

In July 2007, LiveScience® reported that "researchers found the risk of emergency room visits to be 23 percent higher for cats and 28 percent higher for dogs on days surrounding full moons."

Whether the "full moon effect" is real or imagined, the idea of the moon having an influence over animals and people has persisted for ages. Some scientists are sick of the controversy and have even taken a stand on the subject. David E. Campbell of Humboldt State University wrote in 1982, "Research on the relationship between phase of the moon and human behavior indicative of 'lunacy' should not be encouraged," in a short abstract with the subtitle "When enough is enough".

Despite Dr. Campbell's plea, with data this interesting, study results so varied, and fascinating personal stories, I doubt the question will be put to rest any time soon.

So what do you think? Are you wilder during a full moon? Does your dog seem to bark more? Can you think of a way to test your theory?

No comments: