One chuck, Two Chucks.

In the country of Panama, female frogs choose their mates by listening to the series of the chucks or grunts. During this study, scientists believe that female frogs prefer two chucks over one single chuck. In addition to mating, their grunts attract predators. At night there are bats who prey on these frogs. Scientist also figured out that the bats use the same strategy as the female frogs. Bats judge by the ratio of grunts when trying to find a mate. I found this article quite interesting. What came across my mind is that maybe this shows survival of the fittest. Male frogs compete between each other, so when they have offspring that generation will be a bit better than the previous one.

Article: http://www.nytimes.com/2011/08/09/science/09obfrog.html?_r=1&no_interstitial&emc=Google-Earth