The Life of a Poison Dart frog

In the present Poison Dart Frogs live in the Rain Forest of Central and South America. Their Habitat is the forest floor under the wet plants, leaves and logs. They are not born poisonous when they are first born. As they get older, they eat poisonous plants and insects, which make them poisonous. They grown to be 1-2 inches long. I think that 1000 years from now, cities will be built so big there will be no more rain forests. The frogs will be forced to live under ground in the sewers. There will be no more bugs because the forests were destroyed so they now have to eat rats from the sewer. The frogs will evolve to be darker colors to blend in and become bigger with small teeth so they can hunt the rats.