A clever African toad learned to copy a deadly snake to trick predators out of eating it

22:15, Wednesday, 23 October, 2019
A clever African toad learned to copy a deadly snake to trick predators out of eating it

The Congolese Giant Toad shares its rainforest habitat with one of the most fearsome snakes in Africa. But mimicry might be the key to its survival, even without the fangs.
     In a feat of ingenious costuming, the wily toad has learned to impersonate the venomous Gaboon viper to fool predators. The findings, published in the Journal of Natural History, mark the first time researchers have recorded a frog emulating a venomous snake.
     It's a form of Batesian mimicry, when a harmless species mimics the appearance and behavior of a venomous one to confuse predators and protect themselves.
     Mimicry has long benefited the animal kingdom. There's a praying mantis species that disguises itself as an orchid to avoid predators and attract prey, and the burrowing owl has learned to copy a rattlesnake's menacing hiss to scare off squirrels that invade its burrows.
     But this is the first frog to learn the trick, and it seems the disguise has worked. Predators avoid the toad far more often than other species, researchers said, even though its size and caloric value make it an enticing meal.The Gaboon viper is the largest of its kind in all of Africa at more than 6 feet long and 45 pounds. It's got the longest fangs of any snake in the world and a potentially fatal bite.
     The Congolese giant toad doesn't have any of those, but it can mimic the deadly viper's beige-and-brown speckled head. The two share a common habitat in the Democratic Republic of the Congo's rainforests.
     The toad is tan in color, with two brown dots and a dark brown stripe that runs down its back. Its sides are dark brown from the snout to the hind limbs, which mimics the open mouth of a Gaboon viper, and it has slightly raised horn-like "brows" above the eyes, similar to that of a snake.The toad's horn-like ridges over its eyes resemble similar structures on the snake's face. Predators instinctively avoid the Gaboon viper, so it's smart camouflage for the frog.
     But the impersonation doesn't stop there. The toad copies the hissing noise the Gaboon makes to fend off predators with a similar sound that resembles air being released from a balloon, researchers said.
     It even lies flat when disturbed, cocking its head and drooping its eyes to appear like the limbless predator when it's ready to strike.

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