To avoid poisonous prey, young bats have developed a “caller ID”
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To prevent being poisoned, some animals rely on visual clues. The frog eating fringe-lipped (Trachops) bat uses sound to find its prey instead of bright colors. It is well-known that the species listens to mating calls of frogs or toads to find its prey. They also learn to distinguish between unpalatable toads and frogs. This is the first time that predators who listen to mating calls, such as bats, can improve their hunting skills over time. The findings are detailed in a study published April 29 in the journal Proceedings of the Royal Society B.
Fringe-lipped bats are a carnivorous species that range from Panama to Brazil. Bat Conservation International says that the name comes from the warts-like bumps on the lips and muzzle. These may contain toxin neutralizing factors secreted by the skin of frogs. These bats are among the best eavesdroppers on the planet. The bats have been shown to be able to detect the sexual advertisements of over 12 species of frogs and toads. A fringe-lipped frog or toad call will cause a bat with fringes to fly towards the sound in just a few short seconds. Not every call of a frog or a toad is a guarantee for a healthy and safe meal. A bat could be in danger if the amphibian is too big or emits a toxic substance. As a means to adapt to the risk, fringe-lipped frogs developed a system that is similar to the caller ID feature on mobile phones. The bats will not respond if they hear an unpalatable call. Scientists did not know how bats could distinguish between palatable or unpalatable calls because frogs and toads do not have automatic “spam”, like our phone calls. Logan James, co-author of the study and a postdoctoral research fellow at the Smithsonian Tropical Research Institute, said that it was “truly remarkable” that bats could hunt by using calls from an entirely different animal group. We knew that these bats were very intelligent and could learn in experiments. However, we hadn’t tested if their ability to learn played a part in fine-tuning the responses they gave to the sounds of their natural prey. The frogs included a mixture of species that were toxic or too big to handle.
First, the team confirmed that previous studies showed adult bats respond more strongly to animals they find palatable than those they do not. The team discovered that juvenile bats didn’t make the same distinction. The younger bats, on average, did not respond to the calls of frogs and toads differently based upon their palatability. When they looked closer, the team found that juveniles were able to identify larger prey species by their calls but not toxic species. It is likely that juveniles respond to the size of their prey at an earlier stage in development but learn over time to identify toxic species. We have studied this species for many years and we know its behavior in many ways,” said STRI scientist and study co-author Rachel Page in a press release. This was the first time that we tested juvenile bats. It was fascinating to see how young bats, just like children, needed time to develop their discrimination skills. The fringe-lipped bats, however, are not the only predators that can eavesdrop on sounds and distinguish between palatable and unpalatable prey. This study shows, according to the team that this type of experience is crucial for shaping predatory behavior in the wild. This study, according to Ximena Bernardal, a co-author of the study, a research associate at STRI and ecologist with Purdue University said, “Highlights how development and learning can shape eavesdropping behaviors, a insight that could extend beyond bats and other predators who also navigate complex sensory environments.” More deals, reviews and buying guides
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