Naturalists in Australia have expended decades battling to contain the explosive spread of cane toads, an invasive species of hardy- and poison- amphibian that eats just about anything.
Native to the Americas, cane frogs were purposefully introduced into the state of Queensland in 1935 to control the beetles “thats been” eating valuable sugar cane crops. The program quickly backfired, however, when the frogs began multiplying exponentially in their new surrounding. From the original 3,000 immigrants, an estimated 1.5 billion toad descendants now live across northeastern Australia and are inexorably marching southward.
The large terrestrial toads have no natural predators in Australia thanks to a potent toxin, known as bufotoxin, secreted from glands across their backs. Though many species in South and Central America have evolved to eat cane frogs anyway, bufotoxin is deadly to nearly all Australia wildlife- even 8-foot-long( 2.4 -meter-long) freshwater crocodiles. The warty invaders have proved especially dangerous for curious the bag of cats and puppies( and ill-advised people) that induce contact with them.
In an attempt to prevent future casualties, researchers are qualifying wildlife to avoid the cane frogs use a “taste aversion” strategy, wherein sausages containing a small proportion of toad meat are distributed to carnivore populations in regions where the toads have not yet established. After experiencing what is, essentially, disagreeable food poisoning, the predators learn that it’s a bad mind to eat the toads.
But Australian crows don’t require human help.
Australian Geographic photographer Steve Wilson has captured photographic proof that clever corvids north of Brisbane have figured out how to make a banquet of the toads without absorbing any toxin.
“Crows avoid contact with the ooze by grasping them by the legs or even the bony brow above the eye, avoiding the body itself, ” wrote Wilson in Australian Geographic.
“These clever fowls have learnt to roll the frogs onto their backs, sometimes doing so repeatedly if the luckless frog tries to hop-skip away. Crows know which bits to eat- fleshy thighs, tongues, intestines- and how to get at these from below without contacting the lethal parts.”
Anecdotal reports recommending crows in other regions have mastered this crafty technique have circulated since at least 2007, but supported sightings have been limited.
Wilson writes that the crow he spotted spent about 40 minutes carefully picking out the safe parts of the toad while other crows stood and watched.
The presence of attentive eyewitness may explain how crows living over 3,000 miles away from Brisbane have exhibited similar behaviours. Crows are well known for their ability to learn from one another. It’s equally possible, nonetheless, that multiple populations have figured it out independently, given their inclination for problem-solving.
A Nambour resident reported seeing a crow exhaustively cleaning a captured cane frog in his fowl bath before flipping it over and chowing down.
Regardless of how they get the job done, Australians are in full support of the crows’ new talent.