I don’t know about you, but when I am stressed by loud noise, my vocal sac coloration decreases and I’m just not as attractive as I can be. I have tried everything in my makeup kit to improve things, but alas, background noise can be deadly.
Thankfully I am not a European Tree Frog though.
An interesting experiment was carried out in Lyon, France and published in Conservation Biology. These researchers recorded normal highway traffic noise and then played it back 24/7 to 20 male frogs, for ten days. After the ten day period, the vocal sac coloration had significantly decreased and the stress level, as measured by corticosterone levels from the frog saliva, had increased by 58%.
Weakened immunity was also found after the noise exposure and the phytohaemagglutinin swelling test indicated that noise-exposed frogs were 19% weaker than control frogs kept in a quieter environment.
And of course, the vocal sac was much paler-colored in the noise-induced group of frogs which, as everyone knows, is not great at parties and when trying to attract a mate.
Previous studies of environmental noise, whether for marine based life or land based life tended to concentrate on a disturbance of communication, and while that is certainly important, the effects of excessive environmental noise exposure can increase stress levels and have other sequalae that go beyond the coloration of our skin.
Of course, this is not new and we have known for decades that children learn better in schools that are quiet with significantly improved reading scores. In fact, there is one case study performed in New York by Arlene Bronzaft showing that children in a quiet part of a school away from railway tracks had a significantly higher reading ability than those same, age matched children who were unfortunate enough to have a classroom adjacent to the railway.
Now, music is not noise. Well,…actually it is. When it comes to the complex time varying attributes of music or that of speech, or that of noise, there really isn’t that much difference.
Noise and music can be very similar in spectral and temporal make-up. Yet, one is considered pleasurable and the other abrasive- it really is all a matter of perspective. Perhaps if the European tree frog underwent some behavioral cognitive therapy, perhaps the road noise would not be as bothersome to them?