I guess they went for the 4 basic colours; with frogs getting green and ducks getting yellow, that left red and blue for either the beavers or the turtles.
Though some poisonous frogs are all kinds of colours, so they could've given blue to the frogs and green to the turtles.
This begs the question: why would green be a basic color?
Red, blue, and yellow are primary colors, so that makes sense.
but any problem cannot be found