The discovery that frog tadpoles can make sounds also raises the possibility that a host of aquatic larvae communicate in a similar way. That tadpoles communicate somehow is simply amazing 
 
 Dr Guillermo Natale 
 
 National University of La Plata, Buenos Aires Scientist Dr Guillermo Natale of the National University of La Plata in Buenos Aires, Argentina, and his colleagues, were studying the mating calls of adult frogs. Many adult amphibians use loud sounds such as croaks to advertise their presence, and often to attract sexual partners but until now researchers did not realise amphibian larvae might also produce sounds underwater. That changed when Dr Natale caught a horned frog tadpole in a pond using a hand-held net. Scientists in South America have discovered that the larvae of the Argentine horned frog, a species remarkable for its tendency to try eating anything that passes, emit a "brief, clear and very audible metallic-like sound" when they feel threatened. C. ornata tadpoles are difficult to find in the wild, so the researchers caught a wild pair of breeding adults, and began a programme to rear the young amphibians in captivity. Horned frog tadpoles are naturally aggressive and carnivorous, often eating the tadpoles of other frogs, and it is possible that the scream is mainly emitted when another horned frog tadpole moves to attack it as a measure to avoid cannibalism. The researchers found that when horned frog tadpoles come into contact with, or are prodded by, an external object such as a metal spatula, they let out a brief, metallic sound consisting of a short series of higher frequency pulses. The tadpoles produce the sound by pushing air out of their lungs, which develop very early; tadpoles that are just three days old are capable of emitting loud distress signals.
– Scientists studying the calls of adult Argentine horned frogs were amazed to discover that the species' larvae also make sounds—screams even, reports the Independent. The tadpole's scream is a "brief, clear and very audible metallic-like sound," say researchers. They believe the distress calls save the tadpoles from being cannibalized by adults of their species, which is known for its willingness to eat anything it can, including other kinds of frogs. This is the first time underwater larvae or any vertebrate larvae have been known to make sounds, the BBC notes. The researchers believe the discovery has wide-reaching implications for the understanding of amphibian behavior. "We have definitely underestimated their abilities," says the lead researcher, who now plans to study how other tadpoles respond to the sound.