Crocodiles were taught to stop eating deadly toxic cane toads in Australia (newscientist.com)

Toxic cane toads are an invasive species in Australia, brought to the country in the 1930s to control agricultural pests. Native species like freshwater crocodiles eat them and die. Now a team has found a way to train the crocodiles and other lizard species to avoid the toads by substituting a non lethal toxin in toad carcasses.

Public Service Annoucement: If you only watch one informative documentary about the Cane Toad issue in Australia, make sure it's

Cane Toads: An Unnatural History (1988) https://en.wikipedia.org/wiki/Cane_Toads:_An_Unnatural_Histo...

    Lewis avoided harming toads and other wildlife during the production of the film. During a scene in which a man talks about intentionally running over toads with his car, footage appears to show a car swerving to hit toads. To simulate this, Lewis used potatoes which when shot at a distance appeared like toads on the road.

https://www.youtube.com/watch?v=wkxwrpJg5W0