There’s No Wrong Way to Make a Tadpole (or Froglet)

Marsupial frogs, “vomit frogs” and foam-spewers reveal the glorious range of frog baby-making techniques

You ain't seen nothing yet. (Charles Schug / iStock)
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You’re probably familiar with the story of how frogs make more frogs. It goes like this: When a lady frog and a dude frog love each other very much, they play a little game of piggyback that results in fertilized eggs. They deposit those eggs into a pond or stream where they will eventually hatch into tadpoles. After a few weeks, those little squigglies turn into adult frogs through the magic of metamorphosis.

The problem is, that neat template isn’t strictly true. Some frog species lay eggs in trees. Others lay their eggs on land. Heck, some helicopter-parenting frogs superglue their eggs to mom’s back and carry them everywhere until they’re fully formed froglets. There are even frog species who skip the whole tadpole thing altogether and others that give live-birth—out of their mouths. Yeah.

When it comes to frog reproduction, scientists are finding that exceptions are the rule. “I don’t think people have a clue as to how unique some of these frogs are in their developmental and reproductive patterns,” says Kenneth Dodd, a herpetologist at the University of Florida and author of Frogs of the United States and Canada. Partially, that's because we’re sheltered: Many of our researchers come from places like the U.S., where amphibians tend to follow the “traditional” trajectory of egg-tadpole-frog.

For the really freaky stuff, it turns out, you have to look to the tropics. So hop along for the ride, and get ready: It's going to get weird. 

Tadpoles in the Sky

In central Panama, female Vicente’s poison frogs climb high up into the forest canopy in search of a bromeliad—one of the crazy plants that like to hang out on the branches of other plants. Some species of bromeliads hold water like a pitcher, which makes them the perfect froggy breeding grounds. Once she finds one, momma frog squirts her egg in: just one per bromeliad.

But here’s the thing about growing up in a cup of plant water hundreds of feet above the ground: “There isn’t a whole lot to eat,” says Dodd. “So (the mother) comes back periodically and drops in another unfertilized egg as food for the tadpole.” That’s some seriously Spartan parenting. 

Editor's Note, July 19, 2016: This story has been corrected to clarify that the male glassfrog, not the female, urinates on the eggs. Additionally, in Silverstoneia flotator, the male transports eggs, not the female.
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