a whistling thorn is an acacia tree which is commonly seen on the savannas of east africa. if you stand next to the tree, you might hear it whistling. the noise comes from the wind blowing through holes in swellings at the base of the thorns, which act like tiny flutes. thanks to its musical ability, the acacia tree is called the whistling thorn. the swollen thorns provide homes for particularly aggressive types of ants, the acacia ants. in addition, the tree produces sugary secretions that feed the ants. in return, the ants protect the tree from animals. in fact, this particular acacia doesn’t have the toxic chemicals that keep away insects and animals like other species of acacias do. so, when a giraffe tries to grab a mouthful of leaves with its tongue, the ants swarm out of their thorns and attack with vicious stings.

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