By Susan Milius
Borneo’s tree-hole frog may come as close to playing a musical instrument as any wild animal does, according to new tests.
Plenty of animals make structured sounds, but this inch-long rain forest frog adjusts its vocal performance to create a specific quality–resonance–from an object in its environment, says Björn Lardner of the University of Lund in Sweden.
That object is a tree with a cavity holding a puddle of water. Courting males of Metaphrynella sundana sit partly submerged in these puddles while chirping nighttime advertisements for females. When starting his call, the male raises and lowers the pitch until it hits the frequency that resonates in his particular cavity. Then he lengthens individual calls and shortens the time between them as he settles down for serious chirping, report Lardner and Maklarin bin Lakim of Sabah Parks Research and Education Division in Malaysia.