Eggs laid on the undersides of leaves by the glass frogs Hyalinobatrachium fleischmanni depend entirely on fathers for care. And, says Jesse Delia of Boston University, “some are just bad dads.” ...

Here a male glass frog (H. fleischmanni) broods eggs to keep them wet for three to 19 days after the mothers lays them. The eggs can hatch anywhere from 12 to 27 days after they are laid.

The glass frog (Hyalinobatrachium fleischmanni) can turn two or three times more transparent when it sleeps, by hiding almost all of its red blood cells in its liver. The organ conceals the blood ...

The organs and developing eggs of a female glass frog, Hyalinobatrachium mashpi ... In the lab, scientists took captive fleischmanni's glass frogs and put them through a series of imaging techniques.