He builds her a cozy love nest. He woos her with long serenades. Once they start a family, he babysits. The guy is such a catch that one lady after another shows up to play house with him.

That's good news—because the more the southern corroboree frog (Pseudophryne corroboree) procreates, the better the chance of saving one of Australia's most famous and endangered amphibians.

At the start of breeding season the quarter-size male uses his hind limbs to sculpt moss into a chamber near a water source. He keeps up a courtship call until a female enters the nest. She lays 15 to 38 eggs, onto which he directly deposits sperm. She departs; he stays. All season he keeps calling, welcoming up