I'm A Sexy, Sexy Frog

The planet is home to a great many attractive amphibians, but one of the very prettiest is the Panamanian golden frog (Atelopus zeteki). These tiny frogs (in point of fact, they are true toads of the family Bufonidae) were once common along the high country streams of Panama. They are 2 to 2 ½ inches long and weigh less than an ounce. Most could sit comfortably on a silver dollar.

Males and females share similar coloring; yellow backs with unique patterns of black blotches, and uniformly yellow bellies. As is common among tropical and subtropical reptiles and amphibians, the golden frog’s bright coloration is a signal to would-be predators that the frogs are poisonous, and therefore a really bad snack option. The golden frog secretes through its skin a poison all its own, a toxic nerve agent called “zetekitoxin.” The nerve agent is poisonous to humans but it would take a great many golden frogs to secrete enough of it to do one of us any serious harm.

They prefer habitats along rocky streams, the faster moving the better, where they spend their days hopping about in search of invertebrates to nosh, such as ants, beetles, wasps, spiders and caterpillars. Male golden frogs hang around very close to the streambanks, within their small territories. They are joined there, during mating season, by their far larger female counterparts. Apart from when it’s time to mate, female golden frogs spend their time tucked away in the forest, eating and getting plump.

A Panamanian golden frog does not have a tympanum (eardrum), the thin vibrating membrane that enables creatures across many phyla to capture and process sound. Because of this, the golden frog is often referred to as an “earless” species. What’s interesting though is that it seems to have little difficulty assessing the direction from which a sound originated, and it responds readily to vocalizations produced by its own species.

There is not yet a consensus among scientists specializing in Bufonidae as to how they “hear” without “ears,” but it seems that the little frogs register vibrations to some extent, either in the bones of their skulls or in the air-filled sacs of their lungs. In any event, Panamanian golden frogs communicate well enough with one another to generally get on with their froggy business.

Which brings me to the thing I like most about Panamanian golden frogs: their non-vocal communication skills.

All male golden frogs make a distinct vocalization, a high-pitched trilling note that segues into a lower sort of rumble (insofar as a creature that would feel comfy in a shot glass can rumble). The problem is that most of the time male frogs are ensconced along the banks of rushing streams, and their calls are drowned out by the din. So what’s a male frog supposed to do if another male trespasses on his territory? More to the point, what is a randy male frog to do when the lovely lady frogs can’t hear his best pickup lines?

Panamanian golden frogs are nothing if not polite. Contretemps between males are fairly low-key affairs, almost always having to do with territorial encroachment and/or opportunities to woo the opposite sex. When two male frogs start getting on each other’s nerves there ensues, not a violent tussle, but a sort of minimalist dance battle. The frog that “owns” a particular stretch of streambank will turn to face the interloper, and then stick one leg up in the air, holding it there until the other frog gets the message. If the initial message is not received the put-upon frog has no recourse but to hold a second leg up in the air, an indication that he really means business. 

Particularly aggressive interlopers will sometimes respond to a hoisted leg by hoisting one of their own, and that’s when the fireworks really get going. In no time, the banks of the stream are festooned with grumpy frogs raising and lowering their legs in slow motion. In the end one or the other of the combatants concedes defeat and slinks off into the foliage to ponder his now smaller place in an unforgiving universe.

A version of this froggy semaphore takes place when Mr. Froggy’s mind turns to thoughts of lust. Although he has a serviceable mating call the sound of rushing water overpowers it, rendering it less than fully useful. So instead, he sits on his patch of riverbank alertly scanning his surroundings for potentially eligible females. Female Panamanian golden frogs are distinguishable from males due to the fact that they are two to three times as big, called sexual dimorphism among scientists.

When Mr. Froggy spies a fetching young damsel (or fetching old damsel; he’s not very picky, bless his heart) he calmly sticks one of his back legs up in the air – a back leg because his back legs are substantially longer than those up front. The move is usually made up of two parts. The leg extends outward and then upward. It stays for a few moments before dropping back into its ordinary position, but the routine is repeated every so often until the fetching young damsel takes notice and pops by for a visit.

If Ms. Froggy is receptive to the display she will allow the male to hop onto her back in the amplexus position from which fertilization can take place. If she is not keen on Mr. Froggy’s advances she will arch her spine and give it a twitch, unseating Mr. Froggy and sending him packing. Once both frogs are comfortably situated in amplexus (which can last from a couple of days to a month or more) they enter the water, where the female frog deposits eggs and the male frog fertilizes them. It’s quite the efficient system.

Watching videos of golden frogs performing their mating waves is really adorable. It’s just so courteous.

Um… I hate to disturb you, but I noticed you over there eating a centipede and I thought: Jeepers! I like centipedes too! Isn’t that a… Um… I don’t think you heard me. Probably because I’m talking to quietly. I do that sometimes. Here, let me waive my leg in the air a few more times. Okay! You’re looking at me now. That’s a step in the right direction. You wanna come over to my rock? Really?? That’s so nice of you! Let me put my leg down. I didn’t mean to leave just sticking up in the air like that. Such a display. You probably think I’m some kind of ne’er-do-well. You don’t? Wow. I mean just… Wow! Would you find it terribly painful if I were to climb onto your back right now? Really!? Oh, golly! I’m just… You’ve just… Just… Just made my whole day! Golly!

Here’s the sad part of the story. The Panamanian golden frog is extinct in the wild. Has been since around 2005. Several things in combination are thought to be responsible for the extinction: habitat loss, pesticides, the vagaries of climate change, and a truly horrid fungal disease called chytridiomycosis, or chytrid fungus, which is decimated populations. Panamanian golden frogs are also routinely sold as pet in the US and in Europe, and kept in South and Central America as good luck charms. Good luck for the people, perhaps, not so much for the frogs.

Still, thousands of the little yellow amphibians are kept in captivity (in zoos, and in breeding facilities) so we can still stop by tiny reconstructions of Panamanian sky forests and watch the lovely golden frogs going about their business. The hope is that these facilities can maintain healthy specimens of Panamanian golden frogs until such time as a way is found to eradicate the fungus that is still alive and kicking in their natural habitat. Two of the best viewing locations are the San Diego Zoo and the Maryland Zoo, in Baltimore. The frogs really are quite lovely, and I highly recommend paying them a visit.

I’ll talk to you soon.