Ranitomeya imitator, the mimic poison dart frog, is the first amphibian ever proven to be completely monogamous.
The depth of commitment between these frogs is simply breathtaking. The female will lay her eggs on the surface of a leaf, and the male will wait patiently for them to hatch.
He will watch over each of his half dozen children, waiting for signs that they are hungry. Whenever they need food he calls in their mother, who lays an unfertilized egg for each tadpole to eat.
The amount of work these frogs put into caring for their young really shows how complex frogs can be.