In the fable, with the intention of crossing the river, the scorpion convinces the frog to carry it on its back. In the middle of the trip, the amphibian is stung and both die. "Sorry, it's my nature," justified the scorpion on his last breath.
But a new study published by researchers at the Butantan Institute and Utah State University, USA, shows a very different reality.
Far from fantasy, the frog, which is not so much in water outside the reproductive period, would have devoured the scorpion before it finished its first communication attempt, and even if it agreed to serve as an aquatic mount, the amphibian he would not have died from being stung.
For the first time, scientists have shown that the cane toad (Rhinella icterica) is a voracious predator of the infamous yellow scorpion (Tityus serrulatus), which has become a public health problem growing in Brazil, with more than 140 thousand cases of poisoning annually.
In research published in the scientific journal Toxicon, herpetologist Carlo Jared, from the Butantan Institute, and collaborators show how the meal happens in a matter of seconds and without any ceremony.
Scientists also injected amphibians a dose of poison equivalent to the sting of ten scorpions, enough to kill rodents and leave a human in a bad state. It looks like they don't even tickle.
To make sure the amphibians were okay after the injection, the scientists offered cockroaches (insects that frogs love to devour). Tongue throwing, swallowing, end. Everything normal.
Jared tells a story of when he first saw this behavior of animals, more than two decades ago, on a cotton plantation farm in Rio Grande do Norte. “The pedestrians stayed after work at the farm gate, with the light on. The light attracted insects and the frogs ate and lounged. The animals were fat, very well fed. ”
“Twice I saw a frog eating a scorpion. It was kind of quick, he used to flounder. It was not the common scorpion in the Southeast, Tityus serrulatus, but the T. stigmurus, from the caatinga. Once I pulled out a rock to see if it had an amphibian underneath it and was bitten by one of those. Incredible pain. The tongue even took on a life of its own, moving in the mouth in pain. But it ended up passing. ”
Not everyone is lucky for Jared. Especially young children and the elderly are at serious risk of dying from being stung by scorpions. About 140 people die each year because of the bites, although the lethality is relatively low, 4 deaths for every 10,000 poisonings.
“The big problem is that scorpionism has always been evaluated from a medical point of view. The great idea of this new work is to alert the biological and ecological points of view. ”
Many say that chickens, which also feed on scorpions, would be good predators, but the encounters would be occasional, since the bird is daytime and scorpions have nocturnal habits.
“Another possible predator is a skunk, the scavenger. But he is scandalous (that is, he lives in trees) and has an awkward floor. I don't know if it would be that efficient, ”speculates Jared.
The moral of the story is that, although frog may not always be liked, it can play an important ecological role. "The key is environmental education," says the herpetologist. “It is a cultural trait to call the animal ugly, disgusting. But it doesn't help at all. It is very sad when people put bleach or salt on the frog's back. ”
The situation of the greedy toad-toad is not very good because of the successive changes in the environment and, one day, they may be extinct. When returning to lakes, rivers or concentrations of water to mate and reproduce, obstacles such as roads and buildings can hinder or prevent the completion of the journey.
In the fight against yellow scorpions, who do not even need males to reproduce and, therefore, quickly occupy any new environment, any help is welcome.
"Nobody is saying that we need to start raising frogs," says Jared. But resources such as the construction of ecological passages and corridors can help in the preservation of the animal, besides, of course, trying to end prejudice against them.
(tagsToTranslate) frog (t) scorpion (t) health (t) environment (t) poison (t) leaf