An African toad has found a nifty way to scare off predators: it looks and sounds like a venomous snake. This strategy of “Batesian mimicry” is common in some other animal groups, but is extremely rare in frogs.
“This is the first example in the world – that we are aware of – of a frog attempting to mimic a venomous snake,” says Eli Greenbaum at the University of Texas at El Paso. “It’s rare for frogs to be involved in a mimicry complex in general.”
Congolese giant toads (Sclerophrys channingi) are found only in the Democratic Republic of the Congo in central Africa.
In autumn 2017, Greenbaum was giving an undergraduate genetics lecture and showed a photograph of a Congolese giant toad. At the end of the class, a student named Theresa Edmondston approached him to say that she kept venomous snakes as pets, and that the photo looked like the head of one of her favourites: a Gaboon viper (Bitis gabonica), which are found throughout sub-Saharan Africa. The snake’s head has a distinctive pattern on its top and back, and the toad’s back appeared to mimic this.
Snakes alive
Edmondston began researching the two animals, and eventually Greenbaum was intrigued enough to start comparing and measuring specimens. “It became clear slowly over time that, yes, there is some very intriguing similarity here,” he says.
The final piece of the puzzle was put in place by Chifundera Kusamba at the Natural Sciences Research Centre in Lwiro, Democratic Republic of the Congo. “He’s got a lot more experience coming across these things in the wild than I have,” says Greenbaum. “He happened to mention, as sort of an offhand comment, that when you come across these things in the wild, they let out a little hiss that sounds like air slowly being released from a balloon.” Greenbaum immediately realised that this could be the toads mimicking the Gaboon viper’s threatening hiss.
The team has also found that the toads tend to live alongside the vipers, which makes sense: a toad living in a viper-free zone wouldn’t scare off any predators because they would be unfamiliar with the threat of the venom. “There are 11 places where they definitely occur in the same place,” says Greenbaum.
https://www.newscientist.com/article/2220447-giant-toad-looks-and-acts-like-a-venomous-snake-to-scare-off-predators/#ixzz6317GmyUt