Bull Session

I say potato, you like potahtos. You wear pajamas, I wear PJs. And a rose by any other name, we’re told, would smell equally sweet. So does it really matter that we all agree on what to call an American bullfrog? 

“HELL, YEAH!” 

That’s the collective cry of taxonomists around the globe raising their voices in indignant protest. (Yes, these are men and women of strong, science-based convictions.) You see, to a biologist who studies the classification of organisms, names are not at all trivial… but they should all be binomial.

Swedish botanist Carl Linnaeus is credited with introducing this ubiquitous classification system, based on bestowing a unique two-word Latin name upon each species, precisely to avoid the kind of misunderstandings that arise when you say ersters and I say oysters.

Or, for example, when one scientist is talking about a fish using one of its common names, “dolphin” (Coryphaena hippurus, aka mahi-mahi, dorado, pompano), and another scientist hears “dolphin” and thinks of a perpetually-smiling bottlenose marine mammal (Tursiops truncatus).

And yet, despite Carl’s best efforts, disagreements persist. As in the case of the American bullfrog, whose official Latin name (Rana catesbeiana or Lithobates catesbeianus, depending on whom you ask) is more likely to be disputed and cause confusion, ironically, than its common name.

The quibble over nomenclature began about 10 years ago and quickly became a quarrel. Darrel Frost, Herpetology Curator at the American Museum of Natural History, suggested a conceptual leap that would divide members of the genus Rana, which includes bullfrogs, into nearly a dozen new genera. Many of Frost’s colleagues, unconvinced that his argument held water, refused to jump into the newly proposed systematics pond.

In response, feelings, opinions, and counter-claims have been aired publicly in peer-reviewed journals. Several years ago, a group of international researchers created a consortium to promote their own preferred adaptation of the froggy family tree. The taxonomy community still hasn’t managed to harmonize this chorus, which is why she says Rana and he says Lithobates.

But hold on… let’s not call the whole thing off just yet.Because, of course, a bullfrog doesn’t need a taxonomist to know exactly who he or she is… once s/he reaches a certain age, anyway.

Sure, there may be some gender ambiguity early on but that’s common among young amphibians. Their sex is determined genetically, although research suggests that for many frog species, exposure to environmental estrogen or variations in water temperature during tadpole-hood can induce male-to-female or female-to-male transitions. Self awareness doesn’t always come easily, and it can take some time for those gender identity questions to work themselves out. Bullfrog development is relatively slow—one to three years from egg to adult, and another two years to reach sexual maturity.

By the time they’re ready to procreate, however, males and females have definite, discernible physical differences. Males are smaller than females, their tympana (external eardrums) are larger than their eyes, and when in breeding condition their throats are yellow; female tympana are equal or smaller in size than their eyes, and their throats are white. There are behavioral distinctions as well—male bullfrogs are territorial over the summer mating season, and quite vocal about it, too; females are relatively silent, although older gals have been known to sing along with the guys. (I have a sneaking suspicion their favorite tune is If I Were A Boy.)

Ok, ok… life, in all it forms, is full of uncertainty and differences of opinion, at the laboratory bench and the water’s edge. But can we all come together on this much, at least? That the creatures featured throughout this post are:

a. Amphibians

b. Bullfrogs

c. Cool.

Everything else is neether/nyther here nor there.


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© 2018 Next-Door Nature. Reprints welcomed with written permission from the author. Thanks to the following photographers who made their work available through the Creative Commons license: Mark Beckemeyer, LadyDragonflyCC, Greg Schechter, Rick Cameron, and Kaibab National Forest.

Hops-itality

pacific tree frog (photo: jacki dougan, creative commons license)

Frogs, including this Pacific tree frog, could use a little help as they try to survive in the 21st Century (Photo: Jacki Dougan, Creative Commons license)

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Fifty years ago, Rachel Carson asked the world to consider a simple question: imagine springtime without birdsong.

Silent Spring addressed an unlikely subject for what was to become a best-selling book—the effect of DDT and other pesticides that persist in body tissue, becoming more and more concentrated as they move up the food chain (a process known as biomagnification). Yet nearly everyone could easily understand that their own quality of life would be diminished should they step outside one sunny May morning to find the dawn chorus had been replaced with a deafening stillness.

green treefrog (Photo: sarowen, Creative Commons license)Thanks to Carson’s courageous stand—and the subsequent public outcry—songbirds and other avian species dodged a bullet.* Now there’s another set of wild voices in the spring choir who could use a hand—the amphibians.

More specifically, frogs.

There are now over 1,800 threatened amphibian species. At least 168 species have gone extinct in the last two decades due to factors such as habitat loss, water pollution, disease, climate change, and invasive species. Additionally, many areas in the U.S. have recently experienced severe drought, and England is currently experiencing its worst drought in decades.

Many frog species depend on ephemeral (temporary) water sources for breeding since they don’t support fish that would eat the eggs and tadpoles. If the ephemeral pools dry up before the young amphibians have time to metamorphose, or if there isn’t enough rain to create pools in the first place, it can result in a missed generation… and a fragile future for frogs.

Poison Dart Frog Sitting on a Leaf (Photo: MoleSon2, Creative Commons license)Kermit the Frog spoke from experience—it isn’t easy being green… or yellow, or red, or black, or blue.

Frogs are essential to the health of wetland, riparian, and coastal ecosystems. Tadpoles feed on algae, preventing blooms that can reduce oxygen levels. Frogs consume millions of insects each year, including mosquitoes and ticks carrying diseases that threaten the health of humans, their companion animals, and livestock. A wide variety of wild mammals (raccoons, opossums), birds (herons, hawks, geese), and reptiles (snakes) rely on frogs as part of their diet.

April 28th was the 4th Annual Save the Frogs Day, established to raise awareness and funds for amphibian conservation. Since many frog species are comfortable living in cities and suburbs, I thought I would pass along suggestions for homeowners who would like to offer some hoppin’ hospitality, courtesy of yesterday’s event organizers:

1.    A Wet Welcome Mat

Fall and spring are the best times to create a permanent oasis for frogs. Kits are available at many garden and home improvement stores, or simply use a container or dig a hole that is deep enough (at least 1 foot at one end) and line it with sand or a flexible plastic liner before adding water.  Keep in mind, you must provide a sloped ramp so the frogs can get out easily.  Slope the liner or build one out of rocks to gradually allow the frogs to get to ground level or out of the pond. (Some nurseries also have floating devices for swimming pools that can allow amphibians who might jump in a way out.)

Don’t clean the water. In fact, add floating plants such as lily pads or leaves to provide cover. Refill slowly and carefully if water levels get low.

Don’t put fish in your pond, as they will munch on your tadpoles and frogs.

2.    Shade & Shelter

Place your pond in a shady spot, preferably surrounded with native plants to attract a tasty bug feast of ladybugs, bumblebees, and other pollinators to also help beautify your yard. You can stack some rocks or turn over a half of a flowerpot beside the rim of the pond to give your frogs a place to sit and eat their lunch as it flies or crawls by.

glass frog (Photo: Josiah Townsend, Creative Commons license)3.    Go Organic

Don’t use pesticides or weed killers. Amphibians absorb water—and any chemicals in it—through their skin. Pesticides and weed killers can run off from land into water and can be lethal to amphibians. Certain weed killers also can alter hormones, changing male frogs into females and reducing the potential of frogs to perpetuate thriving populations.

4.    Patience, Grasshopper

Don’t be tempted to relocate frogs from other areas or stock your pond from pet stores. You may introduce diseases or invasive species and domestically raised frogs will not necessarily adapt to wild habitats. If you build it, frogs will come.

5.    Look & Listen

Become a frog watcher. You will appreciate these wonderful animals more if you can see them in action, and you can help their conservation in the process. The National Wildlife Federation’s Wildlife Watcher program allows citizen scientists to contribute to a growing database of North American wildlife, learn about the animals living in their region, and build a printable checklist of sightings.

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* Although the focus of this post is frogs, wild birds still face many challenges and threats to their long-term survival. You can check out one such hazard here. Others will be addressed in upcoming NDN posts.

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© 2012 Next-Door Nature—no reprints without written permission from the author (I’d love for you to share my work; all you have to do is ask). Thanks to these photographers for making their work available through a Creative Commons license: [from top to bottom] Jackie Dougan (Pacific tree frog in rose); sarowen (green treefrog); Sascha Gebhardt (poison dart frog); ucumari (bullfrog); Josiah Townsend (glass frog).