The tiny creatures emit a powerful ultrasonic scream when they are attacked, as they are simply unable to defend themselves.
The Brazilian Atlantic rainforest is filled with the shrill “screams” of a tiny amphibian in distress, but until now people have ignored their cries. For the first time, scientists have recorded the cry of South American frogs, which they emit at a frequency that is completely ignored by the human ear. However, animals with properly tuned hearing aids are quite capable of perceiving it, writes Science Alert.
The Brazilian leaf frog (Haddadus binotatus) is the most abundant species of frog found in the local forests. Representatives of this species are very miniature: females are larger than males, but even they reach 64 millimeters in length. When leaf frogs are attacked, they cannot defend themselves, so they only scream, emitting an ultrasonic distress call as a defense.
At Focus. Technologies have appeared Telegram channel. Subscribe so you don’t miss the latest and most exciting news from the world of science!
Researchers have long known that some species of frogs use a “scream” to communicate distress or threat to the outside world. Previous research has shown that frogs can also produce ultrasound, but the new study is the first in which scientists have been able to prove this.
According to Ubirat Ferreira Souza, a behavioral ecologist at the State University of Campina in Brazil, science already knows that potential predators of amphibians, such as bats, rodents and small primates, are able to produce and perceive sounds at this frequency, but the human ear ignores them.
Scientists don’t know exactly why frogs use ultrasound, but one hypothesis is that the distress signal is addressed to some animals. However, another hypothesis suggests that a wide range of frequencies is universal – that is, it should scare away as many predators as possible.
In a new study, scientists examined the leaf frog’s defense mechanism, and it turns out that the cry is just one part of it. Scientists have found that when threatened, the frog arches its back, raising the front of its body and opens its mouth, as if preparing to scream. Next, the frog partially closes its mouth and emits a blood-curdling ultrasonic scream.
Leaf frog defensive call
Photo: Acta ethologica
Humans can only hear sounds with a frequency of about 20 kilohertz and below. However, in their work, the team used software to record the frog’s defensive call and found that it ranged from 7 to 44 kilohertz.
The study authors suggest that frogs use such a wide spectrum to scare off as many predators as possible that can perceive such sounds. What’s more, scientists believe that this behavior may actually be more common than we previously thought.
In the future, scientists plan to focus on recognizing exactly how the frogs make their high-pitched sounds, as this mechanism is still a mystery to science. It is speculated that the sounds made by the frogs may be used to scare off predators directly, or to attract the predators’ natural enemies.
Previously Focus wrote about how a giant tadpole “shrinks” into a tiny frog.
