Who Needs to Dissect Frogs When You Can See Right Through Them?

The glassfrog couldn't be more aptly named. After all, his entire underbelly is translucent like glass. Amazingly, that's not the only unique thing about these beautiful creatures. They're also one of the handful of critters where the father actually handles all aspects of parental care.

"Females flee as soon as they have delivered the eggs. Then males stay during weeks in close proximity of the egg clutch, improving its survival probability by maintaining it wet and, sometimes, scaring away predators," says evolutionary biologist Juan Manuel Guayasamin. As a result, the males are also highly aggressive with one another, often fighting for hours.

Link