The tweets of Puerto Rico’s unofficial mascot, the common coqui frog, became higher pitched during the past two decades, while the animals grew shorter. At the same time, the island increased in average temperature.
“We think the animal adapted to temperature change by becoming smaller, which we believe causes the differences in their calls,” said Sebastiaan Meenderink, a UCLA physicist and co-author of a recent study documenting the declining dimensions of the coqui frog, in a press release.
Male coqui frogs (Eleutherodactylus coqui) now average 10 percent shorter than they did 23 years ago. Similarly to how a Chihuauhua dog has a higher pitched bark than a great Dane, the coqui’s mating calls now register at a higher pitch because of their smaller bodies.
The soprano-singing coqui males could have trouble attracting females or defending their territory from other males. Male coqui frogs duel using their shrill “coh..kuii” calls, which gave the frog its name. Rival males chirp back and forth. The first frog to lose the beat also loses this amphibian rap battle.
“If current trends continue unabated, the coqui frog will sound and look quite different before this century is over,” said co-author Peter Narins, a UCLA biologist who has been studying coqui for four decades.
The study compared measurements of 170 male coqui collected in 1983 to 116 males collected in 2006. The average temperature on Puerto Rico increased by approximately 0.5 degrees Fahrenheit between the first and second collections.
Photo: A coqui frog in Puerto Rico. Credit: acevvvedo, Creative Commons, Flickr