About Kieran Lindsey

writer, artist, wildlife biologist, virtual academic, ambivert, disruptive outlier

Fast Food

When humans talk about making a breakfast, lunch, or dinner run, it’s understood that we’re speaking metaphorically. Truth be told, we’ll probably drive, not jog, to a local café, convenience store, or Kroger. The same cannot be said about the way greater roadrunners (Geococcyx californianus) grab a meal. Fast food is how these long-legged, long-tailed, long-necked North American cuckoos roll—make that sprint—through life.

I mean that quite literally. Roadrunners are feeble fliers but they can definitely beat feet. Angling the body forward to nearly parallel with the ground as they pick up speed, the tail is held flat, acting as a stabilizer during turns. Their unmistakable X-shaped feet, with two toes pointing forward and two toes pointing backwards, are better suited to life on the run than the typical three-one toe formation of perching bird species. And who needs powerful wings when you can leap skyward, as if propelled by a pogo stick, to grab a snack out of thin air?

If you grew up in the U.S. during the latter half of the 20th century, as I did, you may have some serious misconceptions about this fleet-footed bird, not to mention coyotes (Canis latrans). For example, roadrunners are quick but at top speeds of 43 mph, coyotes are more than twice as fast. Smarter, too.

Moreover, I think Warner Brothers animator Chuck Jones must have grabbed the wrong field guide when he started to sketch, because his roadrunner looks more like an ostrich (Struthio camelus) to me than the iconic avian of the American Southwest. I think you’ll agree that a side-by-side line-up provides plenty of evidence to back up that statement.

Roadrunners do have at least one thing in common with ostriches—both birds prefer more arid, savannah-like landscapes to damp, dense forests. That said, greater roadrunners have been expanding their range, moving east from southern California, Arizona, New Mexico, and Texas, into the juniper, pine, and hardwood stands of Oklahoma, Missouri, Arkansas, and even Louisiana. And while they won’t tolerate densely populated urban areas they are showing up in more open suburban developments.

Like so many desert species, roadrunners have evolved to survive in a low rainfall environment. This includes a gland near each eye that secretes a highly concentrated salt solution, reducing the amount of water lost through their urinary tract. The ability to efficiently use the moisture present in their food reduces the roadrunners’ dependence on scarce surface water supplies.

I have a few more bones to pick with Warner Brothers’ depiction of the life and times of coyotes and roadrunners. For one thing, those cartoon characters would have you believe one is a predator, the other prey. Well, my friends, that’s as wrong-headed as expecting a tiny Acme parasol to protect you from a falling boulder.

The real skinny is that roadrunners are predators, too. Their moveable feast includes just about anything they can catch, including insects, spiders, scorpions, frogs, toads, songbirds, bats, rodents, and lizards. They’ll even pair up to take on a rattlesnake—one bird distracting the serpent, the other sneaking up from behind to pin the head down, rending those venom-delivering fangs moot.

This chick is all business. I’m not kidding.

Once their prey has been dispatched, roadrunners swallow their food whole, so there’s no need to carry around silverware, a la Wile E. Before that hummingbird goes down the hatch, though, there’s an important food prep step that has to take place. Fair warning—the process will make you reconsider the sincerity of that two-dimensional speedster’s goofy grin. I’ll let my friend, fellow wildlife enthusiast, and long-time Albuquerque resident, Janelle Harden, deliver the play-by-play:

“Not everyone would appreciate this, but I know you will! I saw a roadrunner catch a house finch on my driveway the other day. Holding the dead bird by the head, the roadrunner proceeded to bash and thrash the carcass against the concrete curb. Once the skeleton was pulverized and the body limp as an al dente noodle, the roadrunner threw her head in the air, along with the finch, opened her bill, and let gravity do its thing. It was fascinating! Took about 6-8 big swallows, and I swear her eyes got bigger with every gulp!”

I have to admit, I do appreciate Janelle’s field observations, and her description of the roadrunner’s bulging eyes does sounds pretty cartoonish. It’s the kind of thing I could imagine happening to a certain famously incompetent but persistent wild canid. Maybe Chuck Jones wasn’t a total Looney Tunes after all.

Gotta run—that’s all, folks!

Life is better with Next-Door Nature—click the “subscribe”  link in the upper right-hand corner of this page and receive notifications of new posts!

© 2018 Next-Door Nature—no reprints without written permission from the author (I’d love for you to share my work. Just ask first.). Thanks to these photographers for making their work available through a Creative Commons license: Anita Ritenour, Photo KentTeddy Llovet, Alan Harper, LDELD, Jo Zimny, and Nick Chill.

Watchdogs

I heard sharp calls piercing the air, even before I noticed the compound of earthen dwellings, and knew that sentinels had spotted me and my canine companion.

Last autumn, I spent some time in New Mexico. I lived there, between Albuquerque and Santa Fe, for nearly a decade about 10 years ago, and I’d been feeling nostalgic for the high desert, with it’s technicolor sunsets and scents of piñon smoke and roasting chiles. So I packed up the car, settled Dash into his travel crate, buckled my seatbelt, and drove west. I wanted to spend some time catching up with friends over pozole and stacked enchiladas, making a pilgrimage to my favorite spa, and watching for urban wildlife species that are notably absent from my current home-base in Virginia’s New River Valley.

The terrier-boy and I were walking along a suburban easement one afternoon, behind a neighborhood of faux adobe Pueblo Revival style homes, when the cautionary cries began to fly. The barked alarms were not coming from man’s best friends—the backyard pooch patrol was decidedly silent. Maybe they were on a coffee-and-donuts break, or just taking a siesta. All I can say is, residential security companies and neighborhood watch associations could learn a thing or three about vigilance and civilian defense from the citizens of a prairie dog community!Based on old cowboy movies, you might think a drive far beyond the city limit sign would be required to find a prairie dog town, but these southwestern  hobbits have adapted admirably to humans and our sprawling developments. I guess that shouldn’t come as a surprise—after all, we have a good deal in common. Like H. sapiens, prairie dogs (Cynomys spp.) are social mammals. Like people, they can and do organize for the common defense. And, similar to their bipedal neighbors, they’ve developed a sophisticated vocal communication system.

Despite their common name and distinctive bark, these watchful creatures are not canines, but a type of ground squirrel native to North American grasslands. There are five different prairie dog species found in the U.S., Canada, and Mexico: black-tailed (C. ludovicianus), white-tailed (C. leucurus), Gunnison’s (C. gunnisoni ), Utah (C. parvidens), and Mexican (C. mexicanus). While best-known for their namesake call, this burrowing band is no one-hit wonder.

According to research by Constantine Slobodchikoff, Professor Emeritus at Northern Arizona University, prairie dog calls vary based on the type of predator (e.g., coyote or domestic dog, hawk, snake, or human). They even construct sentences, complete with a form of grammar, to convey specific information about the approaching menace, including color, shape, size, speed, and direction. Not a generic “Danger, Will Robinson!” SOS, but a detailed threat assessment along the lines of “Heads-up everyone! There’s a short, square-shaped, white-furred dog and a medium-tall human wearing a blue Marmot fleece jacket approaching on foot from the southeastern quadrant!”

How did researchers learn to decode Cynamysian? (Hey, if you have a better name for the language of prairie dogs, I’m all ears.) By presenting an imitation predator and observing the call and response. For example, the alarm call for “diving hawk” causes all the prairie dogs beneath the flight path to dive for shelter, while those outside the path calmly stand and watch. When a sentry sounds the “coyote or domestic dog” call, everyone above-ground moves toward a burrow, everyone below-ground comes to the surface, and then they all stand near the entrances, rubbernecking. “Human,” on the other hand, must be the equivalent of “CODE RED!” because the whole damn town runs for cover.

Dr. Slobodchikoff found that prairie dogs create new calls to communicate with one another about novel objects. They even engage in social chatter that has nothing whatsoever to do with existential threats to individuals or society. This small talk has been harder to decipher, but I suspect it includes all the gossip greatest hits—friends and family, crushes and break-ups, insults and resentments.

The social nature of a prairie dog town may explain a cultural phenomenon I think of as the Cynomys Wave. This conspicuous (and apparently contagious) behavior, also known as the jump-yip, begins when a single resident spontaneously stands on its hind legs, stretching up and back as if beginning a sun salutation asana. Instead of chanting OOOMMM, however, the creature let’s rip with a high-pitched WEE-OO, similar to the infamous yell that ended Howard Dean’s presidential aspirations . Then, in a scene reminiscent of a circa 1977 football stadium, the whole town jumps up to do The Wave, squealing like demonic dolphins.

Some scientists have hypothesized the jump-yip has a territorial function, as in “Mine, mine, this magnificent mound of excavated soil is MINE, and don’t you forget it!” Others suggest it’s related to alarm calls, serving as an “All clear!” once a crisis has pasted. A definitive diagnosis remains elusive but, regardless of its true purpose, it is certainly attention-grabbing.

Humorous antics aside, not all humans are happy when prairie dogs move into the neighborhood. For example, the sort of person whose self-worth is tied to an manicured, emerald green lawn of putting green smoothness is unlikely to put out the welcome mat for any subterranean species.

Nevertheless, prairie dogs do provide an accidental altruistic service to the larger environmental community, including people: they act as khaki-furred “canaries in the coal mine” for a very specific zoonotic disease. When there’s a sudden die-off in the local prairie dog population, it’s a strong indication that plague (of bubonic fame) has come to town. In some states, Health Department personnel regularly visit prairie dog communities, sampling the burrows for fleas, which carry the Yersinia pestis bacterium. The blood-sucking insects are then tested for plague as a proactive management strategy.

The development of modern antibiotics have lessen the impact of plague on human populations but the disease remains devastating to prairie dogs, inflicting far more damage to the community than mammalian, avian, or reptilian predators. Knowing this, I can’t help but wonder if Dr. Slobodchikoff’s team ever discovered a unique alarm call for fleas.


Life is better with Next-Door Nature—click the “subscribe”  link in the upper right-hand corner of this page and receive notifications of new posts!

© 2018 Next-Door Nature. Reprints welcomed with written permission from the author. Thanks to Alan Howell of Star Path Images for granting permission to use his photo, and to those who made their work available through the Creative Commons license: Josh MoreLarry LamsaToshihiro Gamo, Thomas, and William Currier.

Street Creatures Has Moved!

Six-legged tribute and political commentary in the form of a dragonfly in Bethnal Green, London, UK (Photo by Maureen Barlin, cc by-nc-nd 2.0).

Street Creatures now has its very own home!  Go to https://street-creatures.org and subscribe and we’ll keep sending the urban jungle to your inbox!

Vice Squad

I was just trying to help, I swear.

In fact, the primary directive in wildlife rehabilitation is: First, do no harm. But the indignant male northern cardinal (Cardinalis cardinalis) I had just lifted out of a shoebox clearly interpreted my attempts to do a thorough but gentle intake exam as disrespectful. He spat a curse at me, and before I could blurt out an apology, he clamped that bright orange vice-like beak down on the webbing between my thumb and forefinger with more force than seemed plausible for a creature that weighed less than 2 ounces (57 g). 

There we stood—me holding him and trying not to squeeze, him holding me and trying to squeeze with all of his might. I watched a blood blister forming beneath his pincer but there wasn’t much I could do about it. Any attempt to pry him from my hand risked adding to his injuries. I could only try to remain as still as possible, take deep breaths, and wait for him to let go… even though he appeared firmly cemented in place.


Cardinals are year-round residents in much of the continental U.S., from the East Coast westward into Nebraska, Kansas, Texas, parts of New Mexico, Arizona, and southern California. Familiar and conspicuous, with an easy-to-recognize crest and stop-light bright plumage, even in winter, this species is a perennial favorite of backyard feeder enthusiasts and beginning birders. This species is known to be a courageous defender of both offspring and territory, which may be why it was chosen as the mascot for a couple of national sports teams, and for seven different states.

Songbird beaks often provide a clue, or a blatant disclosure, of the owners’ food preferences, especially if the species is a fussy eater—for example, primarily nectar, or meat, or in this case, seeds. There’s more than one way to crack a hard shell and evolution has equipped other granivores with distinctive but equally effective beak shapes. Even so, the cardinal’s short, thick, cone-shaped bill is typical of an avian seed-eater.

Which is not to imply that these black-masked bad-ass birds demand a solely grain-based diet; approximately 10% of their calories come from fruits, flowers, maple sap, and invertebrates. Moreover, their young are fed insects almost exclusively until they’re old enough to leave the nest and digest seeds.

Hatchlings cardinals don’t start life equipped with the same vice-grip their elders wear on their faces (rather than in tool belts at the waist). Given the sibling rivalry for Mom and Dad’s attention whenever they bring home groceries, it’s probably for the best that the youngsters don’t have access to pinching pliers until after they fledge; pushing and shoving are dangerous enough when the nursery is a twig cup perched precariously in the crook of a tree branch.

Eventually, the baby redbirds bills do morph into their final adult size and shape, although for a while the their adolescent nose may look out of proportion to the rest of their head. Hey, being an awkward teen is all part of growing up. It builds character, or so they say. 

With daily compulsory practice (at least if they want to eat) it doesn’t take long before those gawky bills are wielded like a finely crafted tool that quickly converts a feeder full of sunflower seeds into a pile of empty shells… or, very nearly brings a well-meaning wildlife biologist to her knees.


Back at the rehab center intake desk, the good Samaritans who had handed me the shoebox—a young mother and two small children—watched as I stood stock still, a bright red songbird pretending to be a pair of locking forceps stuck to my hand, struggling to hold back tears of pain (and four-letter words).

It’s been 20 years since I worked at the TWRC Wildlife Shelter in Houston, Texas. I’m not at all sure how long it took for the cardinal to release his grip… what feels like least a half-hour in memory was probably less than 3 minutes in real time. Luckily, there’s no scar on my hand, but my cardinal encounter did leave a lasting mark; the memory of that fierce feathered vice is riveted to my brain.

Life is better with a little Next-Door Nature—click the “subscribe”  link in the upper right-hand corner of this page and receive notifications of new posts!

.

[Thanks to the photographers who granted permission to use their photos, and to those who made their work available through the Creative Commons license: John Flannery, Fred Faulkner, Sasha Azevedo, Kenneth Cole Schneider, and John Flannery© 2017 Next-Door Nature. Reprints welcomed with written permission from the author.]

Treehuggers

I’ve been called a treehugger more than once in my life, and while I know the comments weren’t intended as such, I always take them as compliments. As a sobriquet it’s both true and false: true, because I do spontaneously hug exceptionally handsome or venerable trees; and false, because compared to the practiced professionals who scamper up and down tree boles every waking hour of their lives, my embraces are too amateurish to qualify as authentic hugging.

Sure, as a kid I would climb trees and hang from the larger limbs by my knees. We had several sturdy silver maples in our yard and I loved spending time in these leafy hideouts. But there’s more to being a treehugger than practice. I simply don’t have the body to become world-class, or even marginally proficient. To compete with the Eastern gray squirrels (Sciurus carolinensis) in my neighborhood, whose arboreal acrobatics would make a Cirque du Soleil gymnast green with envy, I would need a significantly different anatomy.

For example, I would need to lose enough weight (and height) to allow the friction created by the pressure of my paws gripping a small branch to overpower gravity’s bullying attempts to push me rudely onto the ground.

A better sense of balance would also be necessary if I were to have any success as a legitimate treehugger. I’m not saying I trip over myself on a daily basis but, as friends and family can attest, when I do fall it’s Charlie-Brown spectacular… and usually on my face.

Tree squirrels, in comparison, are masters at controlling their center of gravity. This can be attributed, at least in part, because they can hold on equally well with both hands and feet.  Here again I’m disadvantaged, and I place full blame on evolution, my DNA, and whichever hominid ancestors of mine, after climbing down from a tree on an African savannah, decided that standing upright and using feet almost exclusively for the precarious task of bipedal perambulation was a much better way to go than remaining quadrupedal.

My filed and brightly polished toenails would have to go, replaced by strong, sharp claws that could easily pierce porous bark or hook onto an uneven edge (completely impractical for someone who wears socks and sleeps under a blanket, though). Whereas humans, including me, need at least three points of attachment when climbing, this adaptation allows squirrels to secure their position with only two attachment points, and to grasp new surfaces at angles most animals would find impossible.

Most important of all, I would need feet that can pivot on a swivel joint, allowing my ankles to rotate backwards so I could hang from nearly vertical surfaces.

If I’d been born a flamboyantly fluffy-tailed rodent then maybe, just maybe, I could latch on to a wrinkle in the tree rind and hang by my toenails while enjoying a leisurely acorn snack. Alas, ’tis the fault in my stars to peer ever and enviously skyward, my feet with their simple-hinge ankles planted on the firmament at the base of the trunk, and looked down upon with curiosity and pity (I assume) from the higher-ups.

Life is better with a little Next-Door Nature—click the “subscribe”  link in the upper right-hand corner of this page and receive notifications of new posts!

.

[Thanks to the photographers made their work available through the Creative Commons license: Mr.TinDC, Artful Magpie, JoeInQueens, and Jed Sheehan.  © 2017 Next-Door Nature. Reprints welcomed with written permission from the author.]

Wingsuit

Southern flying squirrel (Glaucomys volans), © 2014 Peter Harrill, used with permission

Is there any non-human skill people covet more passionately than the ability to fly?

Understandably, early aviation experiments centered around mimicry of birds, complete with flapping arms that were usually covered in feathers. The Greek legend of Daedalus and Icarus is a familiar example, but plumage continued to be part of the trial-and-error approach through the first years of the 19th century, when a tailor named Albrecht Berblinger constructed an ornithopter and then took an ill-fated plunge into the Danube. Those daring young men with their dreams of flying machines… they just didn’t understand the concepts of thrust, lift, and drag, and they couldn’t let go of the idea that soaring requires feathers.

I guess Saturday mornings with Rocky and Bullwinkle were not a part of their childhood.

Skip ahead in the history books about two hundred years, during which heavier-than-air flight went from foolish fantasy to fleetingly airborne, to semi-reliably aloft, to acrobatic enough to decide the outcome of a World War, to commonplace as ~30,000 commercial flights per day in the U.S. in 2017.

And yet…

Aviation advancements and inventions during the greater part of the industrial age were about balloons and dirigibles and planes, i.e., aircraft; human beings remained firmly planted on terra firma unless they could climb inside or hang from some kind of apparatus.

It’s hard to point to a specific aeronautic adventurer as the first to see a flying squirrel, recognized the similarities with their fellow mammal, connected the dots, and think, “Eureka! A wingsuit!” But no one lucky enough to have seen one of these big-eyed nocturnal windsurfers could fail to notice the resemblance to the modern flying suits that have finally allowed human beings to fly free as a bird squirrel, unencumbered by gondola, scaffolding, or fuselage.

Of course, strictly speaking flying squirrels don’t really fly, and neither do the people wearing a wingsuit.

They glide.

The wingsuit mimics a flying squirrel’s patagium—loose folds of skin that span the space between forelimb wrist and hindlimb ankle on either side of the body. Spreading those limbs into a jumping jack X, the furry membranes stretch into a rectangular shape that allows the tiny BASE* jumpers to propel themselves into the air and then slide down the sky at a 30-40 degree angle controlled fall.

© 2008 Steve Collins, used with permission

A long, flat tail is critical for controlling that fall. Serving as a rudder, it allowing 90 degree turns around mid-flight obstacles. The tail is used for landing, too; on the approach, the tail is raised to an upright position while, at the same time, all four limbs move forward to form a kind of patagium parachute. Together, these actions create enough drag to tip the animal’s head and body up as it prepares for impact with a tree trunk or branches, a bird feeder, or a building.

Northern flying squirrel (Glaucomys sabrinus) © 2015 Jukka Jantunen, used with permission

The New World is home to three species of rodent flyboys and flygirls: Northern (Glaucomys sabrinus); the recently differentiated and designated Humboldt’s (G oregonensis); and Southern (G volans). There’s some range overlap between Northerns and Southerns, but the two species are relatively easy to distinguish. Northerns are larger, but the belly of the beasts provides a much more notable difference; the underside of a Southern flying squirrel is creamy white, while Northern flying squirrels are beige below with darker roots.

Humboldt’s flying squirrel

There’s range overlap between Northerns (found from Alaska to Nova Scotia down to Utah and North Carolina) and Humboldts’ (whose limit their travels from British Columbia down into southern California) as well. However, the two are close enough in physical appearance and behavior that it took an examination of their DNA before scientists realized earlier this year (May 2017) that they were looking at not one species, but two. Humboldts’ have been described as smaller and darker than Northerns, but the fact that it took so long for the former to be recognized as distinctive (Southerns were first described in 1758, Northerns in 1801) suggests to me that one would have to do a mighty up-close-and-personal examination to make a positive ID.

All three varieties of Glaucomys have one important feature in common: they’re more risk-averse than you might have assumed. Riding the wind wearing a wingsuit is a dangerous activity for humans — one severe injury for every 500 jumps, according to one study, despite advances in materials, design, and training — but it’s just another day in the life of a flying squirrel. That’s not to imply they never miscalculate a distance, or botch a landing, or are immune from injury (or worse), but they do have concerns beyond thrust, lift, and drag, or changes in wind speed and direction.

Which is why, immediately after sticking the landing, a flying squirrel will scurry quickly to their nest hole, or the other side of the tree, or at least toward a deeper shadow. BASE jumpers and skydivers rarely have worry about avoiding predators waiting in the wings.

[Thanks to the photographers who granted permission to use their photos, and to those who made their work available through the Creative Commons license: Richard Schneider, and Barbogast. The painting of Icarus and Daedalus is by Charles Paul Landon, and the drawing of a New World flying squirrel is by Charles Henry Dessalines d’Orbigny, currently in the University of Washington’s Freshwater and Marine Image Bank; both images are in the public domain. © 2017 Next-Door Nature. Reprints welcomed with written permission from the author.]

*BASE is the acronym that stands for the four categories of fixed objects from which one can jump: building, antenna, span (bridge), and Earth (cliffs).

Long-stemmed

Daddy longlegs are the jazz cats of the arachnid world!

This realization came to me as I watched a single backlit note poised on a broken music staff bebop across the asphalt path in front of me. A soundtrack of jazz piano greats immediately began to play in my head — Willie “The Lion” Smith, Thomas “Fats” Waller, Art Tatum, Thelonious Monk, and Dave Brubeck, to name but a few. Chill dudes whose spider-like fingers strode, slid, bounced, and stomped across the keys.

Jazz has evolved and diverged from it’s start in the late 19th century as  ragtime and Dixieland into a genre so diverse it can be difficult to define, or even to list all the variations: Swing, Cool, West Coast, Modal, Free, Fusion, Funk, Cu-Bop, Post-Bop, etc.

The harvestmen, as daddy longlegs are also known (that even sounds like a 1950s jazz band, doesn’t it?) have an even longer and more impressive history. They’re a vast, improvisational set that spans millions of years and many taxonomic octaves, with over 6,500 named species worldwide (experts estimate there may actually be more than 10,000). And while not all the players in this big band have long legs, the ones who hangout in my neighborhood— eastern harvestmen (Leiobunum vittatum)— are definitely long-stemmed.

These invertebrate daddy-o’s are arachnids but they are NOT spiders; they’re more closely related to mites and scorpions.  Harvestmen don’t have a spider’s tiny waist… or venom… or silk (so no webs)… and they have only two eyes instead of eight.

Jazz musicians need to maintain their instruments to get the best sound; piano hammers need to be voiced, strings tuned, reeds moistened and valves lubricated.  Daddy longlegs are similarly serious about the tools of their trade, cleaning each leg after a meal by threading them through the pincers by their mouths.

Harvestmen are a gregarious lot who periodically congregate in the hundreds or even thousands. Scientists have suggested these spontaneous jam sessions might occur in response to climatic conditions or provide some protection against predators… but it’s pretty clear they aren’t making music (that can be detected by the human ear, anyway).

Members of Order Opiliones are exceptional even among arachnids. They can swallow small pieces of solid food, whereas their cousins are limited to a liquid diet. Conversely, daddy longlegs sip oxygen through their legs into a trachea, while other arachnids respirate through a gas exchange organ called a book lung. That’s probably just a warm-up, though. Like jazz, daddy longlegs are both familiar and mysterious. Little research has been done on these species… and who can say why? Maybe they’re a bit too avant garde to have a large fan base among researchers.

Or it could be the hours they keep and the dives they frequent. See, eastern harvestmen have more in common with jazz pianists than an impressive hand (or leg) span. Say what you will about the pleasures of sitting outside at a warm summer evening festival, lounging on a blanket in the grass while listening to a live performance — you’ll hear no argument from me. But to my mind, jazz is an urban art form, and the smokin’ hot licks happen in basement clubs. An intimate corner, low lights, insulated from street noise, maybe just a little damp…

Now that the kind of gig daddy longlegs’ dig.

 

[Thanks to the following photographers for making their work available through the Creative Commons license: Rob Swatski, Leslie Bliss, Rob SwatskiLuis Fernández Garcia, and schizoform.  © 2017 Next-Door Nature. Reprints welcomed with written permission from the author.]

Vert-de-Gris

Cope’s gray treefrog on a pepper plant. Photo: Alan Howell © 2017, Star Path Images, Used with Permission.

It isn’t easy being green. Kermit the Frog said it, so you know it has to be true.

He’s always seemed a reluctant celebrity, so my guess is that being the most famous Muppet-amphibian on the planet isn’t always a picnic. I wonder whether life would be a little less stressful if, like some of his cousins, Kermit could change from green to another color when he’d rather not be so conspicuous.

North American gray treefrogs know how to be seen and when to blend into their surrounding, shifting the spectrum from bright emerald to peridot, to gold, copper, platinum, silver, and even gunmetal. Since the places they hang out — trees and shrubs in woodlands, meadows, prairies, swamps, suburbs, and cities — tend toward palettes awash with green and gray hues, these arboreal amphibians can keep their sartorial choices simple. 

What looks like a costume change is actually a rather high-tech, cellular-level special effect created by chromatophores. These pigment-containing and light-reflecting cells, or groups of cells, are present in the skin of certain frogs, as well as some reptiles (including chameleons), cephalopods (such as octopi), fish, and crustaceans. Mammals and birds, on the other hand, have melanocytes, a different class of cells for coloration.

Chromatophores are classified based on their hue under white light:

  • melanophores (black/brown)
  • cyanophores (blue)
  • erythrophores (red)
  • xanthophores (yellow)
  • leucophores (white)
  • iridophores (reflective or iridescent)

The process, known as physiological color change, can be controlled by hormones, neurons, or both. Most studies have focused primarily on melanophores because they are the darkest and, therefore, the most visible. When pigment inside the chromatophores disperses throughout cell the skin appears to darken; when pigment aggregates in cells the skin appears to lighten. Either way, you’ve got an amazing makeover, or a convincing disguise, in no time flat! 

There’s even more to the gray treefrog’s ability to assume an alter-ego than meets the eye —what appears to be a single species is actually two very close relatives: Hyla versicolor, aka Eastern, although there’s a long list of pseudonyms from which to choose (there are more ways to hide than blending into the substrate); and Hyla chrysoscelis, aka Cope’s (which also has a couple of nicknames but not as many as H. versicolor).

Cope’s and Eastern are equally skilled at clinging to and climbing slick surfaces using large toe pads that secrete mucous, creating surface tension. It’s not uncommon to find one plastered against a window pane (allowing for an interesting view of their nether-regions). Both species prefer a diet of small insects, spiders, and snails. Both hibernate under leaves, bark, or rocks. Well, “hibernate” sounds a lot more cozy than the reality… which is that their bodies pretty much freeze and their lungs, heart, brain, and other organs stop working until they thaw out and reanimate in the spring. It’s a pretty nifty chemical trick, on par with being able to transform your complexion at will. 

Kermit has an unmistakable personal brand, but distinguishing H. versicolor from H. chrysocelis visually is just about impossible. Both Eastern and Cope’s are relatively small (1.5—2.0 in/3.5—5 cm), and the adults are often mistaken for younglings. Both wear a sweep of bright citrus-orange along the inseam of their hind legs (a signature shade is all the rage, you know).  Females of both species are usually (but not always) larger, with a ladylike white throat. During the breeding season, males have a macho (make that hipster, since it resembles a beard) black, gray, or brown throat. Guys sing. Gals swoon, but don’t sing along.

The ranges of these two species overlap, but Cope’s are more widely distributed. If you find a gray treefrog in North Carolina or Georgia, you can be reasonably certain it’s a Cope’s, but if you’re in Iowa or Pennsylvania, all bets are off. The only risk-free way to know for sure is to do a DNA test — Cope’s are a diploid species, meaning they have two sets of chromosomes, one from each parent (for a total of 24); Easterns are a tetraploid species, meaning they have four sets of chromosomes (for a total of 48).

Now, some frog call connoisseurs claim they can detect variations in breeding calls, and that Cope’s treefrogs have a faster and slightly higher-pitched trill than Easterns. But the call rates of both species change with ambient temperature… so color me skeptical.

[Postscript:  What kind of frog is Kermit? While I’ve never found a definitive answer to this question, I always assumed that because he was created/discovered by Jim Henson, he was probably Hyla muppetalis or Rana hensonii… something like that. However, in 2015 Brian Kubicki of the Costa Rican Amphibian Research Center discovered a frog who, if not the same species, must at least be a first cousin, or possibly Kermit’s doppleganger.]

Diane’s bare-hearted glass frog (Hyalinobatrachium dianae). Photo: © Brian Kubicki, Costa Rican Amphibian Research Center, Used with Permission

[Thanks to the photographers who granted permission to use their photos, and to those who made their work available through the Creative Commons license: Dave Huth(composite of color variations), , Chiswick Chap & CheChe, (melanophores schematic), Alan Wolf, Andrew Hoffman, and Douglas Mills© 2017 Next-Door Nature. Reprints welcomed with written permission from the author.]