The Unbearable Translucency of the Glass Frog


Some people contend that there are too many see-through animals in the world. This is a thought I’d gladly entertain if any of them could tell me how many transparent species would be acceptable; but, they never think that far. There are transparent fish, insects, slugs and octopi. I thought I saw a transparent dog once, but it turned out he was just very badly injured. Some think that transparency is a way for a creature to blend in with its surroundings. A predator looks over and decides that there isn’t anything in that direction but a disembodied set of organs swimming around. Some think that there isn’t a real evolutionary reason for a creature to have its organs on display 24/7, just part of the rich tapestry of stuff. Like the fact that some grasshoppers look like Kevin Costner or the more interesting fact that a lot of them don’t. Frankly, I don’t have time to write about every transparent species of animal, so I’ll just write about one and the reader can extrapolate what I write to other species.

Glass frogs are of the family Centrolenidae and there’s very little anyone can do about it. This family contains three subfamilies: Hyalinobatrachinae, Centroleninae and Allophryninae. Within these subfamilies are over a hundred species of glass frog, each with its own unique degree of repulsiveness. Every member of Centrolenidae is an anuran which is herpetologist-speak for “frog”. Because of their remote habitat, new species are still being found. They don’t want to be, but when they pretend to be a different species, herpetologists see right through that…

In fact, a new species was found last year. The species was found in Costa Rica and dubbed Diane’s Bare-hearted glass frog or Hyalinobatrachium dianae if you want to be insufferable about it. I’m guessing that the frog was named after noted batrachologist Diane Bareheart. An article in National Geographic described the animal as “looking like Kermit”. This came as a relief to those of us who’ve been waiting for National Geographic to dumb their articles down to match the rest of the media. Hyalinobatrachium dianae is only an inch in length frustrating biologists’ attempts to teach them basketball.

From the top, Centrolenidae look like normal frogs… the kind you might see every day, if you see frogs a lot. The glass frog comes in dozens of colors, most of them green. But, flip one over and you get a dissector’s view of the animal’s digestive tract and circulatory system. That’s the beauty of the glass frog: You can perform an autopsy on a it without cutting it open. Just shake it like a Magic Eight Ball and wait for the organ you want to examine to float to the top. Actually, you don’t even have to wait for it to die to perform an autopsy (just shake less vigorously). Fun activities include force feeding a glass frog red velvet cake, then watching its digestive tract change color…

Glass frogs inhabit the Americas, from Mexico down to just north of Argentina. Herpetologists theorize that the species originated in South America, then migrated to Central America in an attempt to meet Bianca Jagger. Centrolenidae tend to live high in the trees. There are few of them in Brazil due to their instinctive aversion to being robbed and beaten as well as a dislike of cross-dressing for parades. Because they inhabit large portions of south and central America, they turn out in huge numbers for the Pan Am games; however, historically, only one has actually competed. The frog, dubbed “Pedro” by the media because they couldn’t spell “Ramon”, entered the Hop, Skip and Jump event in 1966. Contemporary sources stated that his hop and jump were pretty impressive; however, he never did get the hang of skipping.

Centrolenidae males are very territorial. I once read a description of glass frog combat that included the words “grapple fiercely”. Any creature less than three inches in length and toothless does nothing fiercely, but try telling that to a batrachologist. I tell you this just in case you’ve decided to snap up a few on your next trip to Central America in order to get them to fight each other for the amusement of yourself and your friends. It will be disappointing. If gambling is involved, that’s even worse. Try predicting the results when either combatant can be paid in houseflies to take a dive.

Glass frogs tend to eat pretty much what other frogs eat; so, if you are already taking care of a houseful of frogs, a weekend visit from a glass frog won’t facilitate a special trip to the grocery store. Centrolenidae eat insects and arthropods which is another way of saying “bugs”. What eats glass frogs? Snakes, mammals, birds and Andrew Zimmern. Pretty much anything with a mouth and an empty stomach will gobble up a glass frog; and, why not? Due to their translucent nature it is like eating a gummi bear.

What does the future hold for Centrolenidae? Being tree-dwellers, it doesn’t look good for many of them. The Rio Azuela Glass Frog, for example, is red-listed as endangered. Apparently, the creature only thrives in trees that are vertical in nature. Once they are cut down and processed into lumber, the frog loses all interest. Environmentalists contend that these animals are important to the ecosystem; however, once the trees are gone, the ecosystem changes from rainforest to parking lot. The glass frog can’t stand in the way of progress… it must adapt. A good first step? Learning how to skip…