“All the frogs, in their peregrinations, investigated the water holes, and usually went in for a dip.”
-E. R. Dunn, 1941

A dark, speckled frog the size of a walnut climbs a guayacán tree that rises thirty meters from the ground. Its target is the stumpy scar of a large branch that fell off many years ago, which was then hollowed by termites, toucans, and fungal rot. With the start of the rain season, the cavity is likely to fill with water, a miniature marsh suited to the frog’s miniature needs. Precarious though the journey may be, the frog will go to great lengths and heights in search of any such small hollows. It finds them in the forest canopy within the throats of bromeliad plants, in tree holes and broken bamboo stems. It finds them in the bountiful litter of the forest floor, in halved fruit husks and emptied seed pods, and the boat-like hollows of fallen palm fronds.

For a creature so small, the frog hops and climbs with seemingly inexhaustible gumption. It has the enviable advantage of being toxic—the consequence of a diet of ants, mites, small beetles and other arthropods—a fact advertised by its patterning, a muddy brown speckled with mint green dots. Animals learn from prior association that this is a creature that tastes like numbing and nausea, muscle spasms and death. Would-be predators spit, retch, foam at the mouth, and don’t try to swallow again.

Nonetheless, the frog travels with caution. It emerges from the forest edge onto a weedy lawn. It freezes at suggestions of danger—swooping birds, naïve cats, a car backing out of a garage. Now it climbs flower pots and patio furniture. It scales a metal fence post, falls off and tries again. It sits awhile in a dimple in an uneven concrete patio, which sometimes fills with backsplash off the tin roof overhead. It perches on the rim of a disregarded, rusting bean can and looks within—water prickling with telltale signs of activity, mosquito larvae sipping air through siphons that they poke through the water’s surface.

A downpour starts as the frog turns back, and it takes time to belly-scoot in the shallow puddles that form on the paved concrete, collecting water in its bladder. Now, it beelines home—having expanded and updated an internal map of its surroundings, the frog has no reason to dawdle—its future depends on its sense of place. Back on the forest floor, it clambers over and under a shag carpet of leaf litter that will rebound, tent-like, when the rains die back. Finally, it senses the familiar—visual, chemical and tactile cues that lead it back to treasure—a clutch of four jelly eggs laid by its mate a week ago under cover of fallen leaves.

It hydrates the eggs with water from its bladder and kneads the little mound with its back legs to rotate and aerate the developing young. After another week of ministrations, the tadpoles within will hatch and perform the first great feat of their own lives. They will squirm, limbless, up their father’s legs and onto his back. They’ll curl their tails around their heads, and a sticky mucus will glue them in place to their father’s skin. He will then portage his young, in ones and twos, to the scattered accretions of water he remembers from his long journeys away from home.

“[A]n actively foraging Panamanian frog, Dendrobates auratus, averaged about 160 [meters] of movement (6,000 body lengths) in a 12-hour activity period…”
-K. D. Wells, 2007

Ancon Hill heaves out of Panama City as if indifferent to the efforts of civil engineers, a great green whale of a wilderness preserve that rises almost two hundred meters above the urban sprawl. The flag of Panama eddies from the summit, circled by vultures and hawks. The hill’s forested slopes were once partially quarried, partially converted to a switch-backing warren of residences, but the area has since been designated a national monument. Locals and tourists alike drive, bike, or walk up its tarmacked trails for both peace and awe, for views of the city below, framed through gaps in the trees, and for glimpses of wildlife lurking between leaves and branches.

I live on Ancon in a two-story condominium divided into four residences. My neighbors and I share a back patio that looks out onto a strip of forest that slopes downhill about twenty meters before opening onto another paved level of houses—not that we can really see them. Plants grow so profusely in the tropics that my view disintegrates into vegetation. There is no horizon.

And yet, my little fringe of forest contains endless diversions. Here, hummingbirds snap their wings at each other in bouts of aerial aggression. The occasional band of pocket-sized tamarin monkeys chirp in voices pitched high as songbirds as they leap through a jungle-gym of tree branches, palm fronds and climbing vines. Heavy-bodied sloths and iguanas bask in the canopy champing at foliage, while leafcutter ants clip the same into shards that they carry in sparkling green rivers down the trunks and along highways they’ve cleared through the forest litter to their fungus farms underground. With the rain season emerge frogs, enervated by humidity, which they wear as gleaming, second skins. It’s a misconstruction, I’ve found, to think of frogs merely as pond dwellers or riverside inhabitants. In the moisture-laden air of the tropics, many have slipped into much more terrestrial lifestyles, which is how I come to observe a particularly common species hopping across my back patio and, on occasion, scaling the trees just beyond.

This is the green and black poison frog, Dendrobates auratus. Where I live, they’re a fairly nondescript dark brown flecked with pale green dots and dashes, but in the northeastern province of Bocas del Toro, the species has an even bolder patterning of vibrant green splotches against black. Across its geographic range from southeastern Nicaragua to the northwestern forests of Colombia, D. auratus frog populations vary in coloration from blotched to banded to spotted, black shading all the way to cream, lemon green through to sky blue. The species epithet auratus, “of gold,” refers to the color variant first described in scientific literature. Found on the Taboga and Taboguilla islands off the coast in the Bay of Panama, this variant is also one of the most far-flung—a small population has persisted in Hawaii since 1932, when they were introduced to the island of Oahu in an attempt to control mosquitoes.

It is because of mosquitoes that I know anything about these little frogs at all. In an effort to rid the area surrounding my house of standing water bodies—prime breeding ground for mosquito larvae—I come upon tadpoles in the most eccentric of hollows. I find the first three in a rusted bean can, in inch-deep, murky water. A couple flicker in the warped concavity of a plastic outdoor shelf. One pours out of a giant conch shell abandoned in the front garden by a former occupant of the house. A couple dozen startle in the bottom of a plastic crate used to prop up a plant pot. And around the side garden, in a large, shallow tub brimful with rain off the roof, are so many tadpoles I finally lose count.

“Thus not less than three adult males, and probably five or six, came to the same hole to deposit larvae at different times during the period of observation.”
-T. H. Eaton, Jr., 1941

The rainforest is a fractal landscape of possibilities, with light and warmth and wetness enough to sustain a profusion of life forms. But the paradox of plenty is that there are too many competitive interests for any one organism to dominate the landscape. Instead, each species must trace an intricate pathway to survival across this teaming terrain, sinking tendrils and toe-tips into niches no other organism could occupy.

In the Neotropical forests of Central and South America, green and black poison frogs and their relatives found their foothold by abandoning streams and rivers, where their ancestors reproduced. Instead, they lay their eggs on land, safe from the depredations of waterbugs, fishes, diving beetles, and the like. Since water remains amniotic to the continued development of tadpoles, poison frogs have evolved preferences for alternative sources—naturally forming pools on the forest floor or, in the case of the more arboreally inclined species, ephemeral “plant marshes” called phytotelmata, which form within bromeliads and other kinds of plant cavities.

The frogs must rove far and wide to find these nursing pools, which fill and dry with the rains. They must have inquiring minds, good memories, an excellent sense of direction. They must invest time and energy in caring for their vulnerable young, a task whose odds are significantly improved if more than one parent is involved in the process. Depending on the species, females, males, or both parents have evolved to guard their eggs, protect them from desiccation, infection, or predation, and transport the hatchlings to water. Species like the strawberry poison frog, Oophaga pumilio, go a step further—mothers pay repeat visits to their tadpoles to lay unfertilized eggs for them to feed on, without which the tadpoles would starve to death.

Meanwhile, the tadpole of a green and black poison frog can survive unattended in just about the amount of water you can hold in a cupped palm. Imagine this world inside your hand—a slurry of decaying plant matter, microbes and mosquito larvae. Every day the surface breaks as raindrops pour into your little reservoir. The tadpole swims in opposition to flowing water because if it followed the current, it would spill over the edge of its container world. It’s wired to know this truth. It lurks in the debris, feeds opportunistically—the mosquito larvae haven’t a chance against it.

As the tadpole grows, it darts upward to take bites of air from the pool’s surface, testing a life out of water as lungs develop behind its gills. Weeks pass. The rain clouds disperse and that tiny accretion of water starts to dry out. It’s a shot-glass, a thimble, a teaspoon. The tadpole, little pip of a thing, tests the tiny muscles of newly sprouted back legs in a murk too thick to swim.

The rain clouds return just in time to replenish the tadpole’s little cup. It breathes deep again. It swims again, its hind legs learning to frog-kick while front legs elbow through a body enclosed too long inside that oversized tadpole head. It stops eating. Its beak dissolves into a toothless, wide mouth. A tongue forms. A coiled intestine straightens. Eyes rise, turn binocular, learn to focus out of water. Toes ossify, perfect and delicate as flower stamens. Black skin turns brown, develops faint green spots. The tail withers. A brain that once swam against the current must learn to climb, to cling, to jump.

Spread your hand wide. Imagine a froglet not much bigger than a fingernail perched on your index fingertip. Leap across the void from fingertip to thumb.

Once, you might have found yourself resting on a tree branch thirty meters above ground, sunlight rippling through a leaf canopy thick overhead and thick below. Today, you feel plastic. Hop forward onto dirt. Now a leaf. Now Styrofoam. Now a wider stretch of dirt. Welcome, froglet, to the rest of your life. There’s grass up ahead. You’ll make it.

“Parental attendance of offspring thus makes possible, with varied degrees of certitude, continued parent/offspring recognition as larvae mature.”
-B. Waldman, 1991

Constricted by highways and urban development, the city bellows its presence around the forest island of Ancon. Passing trucks staccato-shift their gears in heavy traffic. Planes taking off from the local airport rattle the windows and puncture our conversations. A kilometer’s distance to the west, the Panama Canal opens its mouth to cargo and passenger ships from the Pacific, whose horns float over land with the winds.

The luckiest among us—humans, to be specific—live in a world like this, where the built and natural environments rough-rub against each other, insistent upon coexistence. The luckiest among us are visited by frogs who seem so perfectly formed for another world that the mere fact that they live in our back yards imparts a sense of wonder bordering on worship.

I decide to adopt the tadpoles I find around my house, and end up raising hundreds over the course of the eight-month rain season. First in recycled plastic food containers, then in a refrigerator drawer repurposed from a junk pile into a small outdoor pond. I put an aerator in the tank, and then remove it when I realize the youngest tadpoles get sucked in by the pump. I put in rocks and vines for the tadpoles to play games of hide and seek, buy granulated fish food to supplement their diet of whatever ends up in the makeshift pond as a matter of course—insect larvae, twigs, seeds, algae.

My back patio becomes a magnet for the neighborhood’s D. auratus frogs. The males visit almost daily, their backs pearled with fresh-hatched young. They are cautious but determined. If I move too quickly, they nip for cover or turn back for wherever they came from. If I move as slow as tree boughs, they ignore my presence, which is how I come to squat at the lip of my pond for half-hour stretches, camera at the ready, mouth agape.

A D. auratus frog can swim, if it needs to, but seems to prefer to cling to the edges of pools with just its tadpoled lower half dipping below the waterline. If startled, the frog will dive into the debris and linger until it assesses that it is safe, or until it runs out of breath. Sometimes, the frog will dive and then float, looking for all the world like a plastic bath toy, its nostrils peeking through the water’s surface while its body hangs vertical, limbs splayed, waiting. Sometimes, it will reach behind with a hind leg to gently stroke the tadpole quiescent on its back.

This is the tadpole’s moment. Overland, it has remained securely attached to its father’s back, held by a thin film of mucus. Underwater, it begins to fidget within that invisible, now dissolving adhesive. Once its tail comes free it squirms with full force, nearly vibrating as it tries to beat itself loose of the last threads of glue that bind it to its father. The gap between them widens, unseen threads holding the tadpole’s head to the frog’s skin, but eventually, these snap too. The frog darts to the pool’s edge. The tadpole sinks to bottom of its new home, nearly motionless after its exertions.

I marvel at this sequence of behaviors—from the intentionality of the frog’s guarded approach to the pond, to its delicate suggestion to its young that it’s time to leave. The tadpole’s little body quivering into overdrive to release itself to an uncertain future, its seeming hesitance to do anything more in those hours after leaving its father’s care save for a few tentative nibbles, a little tail flick.

D. auratus tadpoles become more energetic as they grow bigger. By the time the buds of their hind legs develop, they’re monstrously fat-headed and beady-eyed, and peck irritably at whatever comes within reach. By late summer, I have to admit to an overpopulation crisis—the larger tadpoles have started to bite at each other, nicking tails and mangling delicate hind buds. Many young tadpoles die. The ones that remain eat up the corpses, starting at the soft belly and leaving behind ghostly skins scraped down to the spines.

I move each tadpole into its own little plastic party cup after this, and place the lot within our screened-in porch. For more than a week, the fathers continue to visit, clambering up the insect mesh in search of some point of entry. I imagine they smell the tadpoles or sense the water—they’ve never been curious about the inside of the screened porch before. Eventually, they lose interest, and I see frogs with less frequency once they realize their pond is gone for good. On occasion, however, a passing male will divert from his journey to check out the old refrigerator drawer, emptied, dried, and propped up against a wall. He will spider up the sheer cliff of plastic, fall, cock his head, calculate, and try to climb again. I think he recognizes this object’s contours even if he cannot understand where the water has gone. I lurk guiltily within the screened porch. It’s a long while before he gives up.

“[S]earching foragers apparently cannot rely solely on concealment, and without exception these species possess powerful skin toxins.”
-C. A. Toft, 1981

Concurrent with my back patio obsession, I dive into scientific journals and exotic pet forums online. I have by now collected an embarrassment of factoids about D. auratus frogs and their relatives. I learn that a male D. auratus frog maintains a territory in the leaf litter from within which he’ll chirr in a low voice to attract females. I learn a female can be possessive of her mate, driving off other females, or seducing the male away from her competitor. Males maintain several clutches of eggs at any one time, from multiple mates. Females that discover eggs they did not lay may eat them up. Males disperse the siblings of one clutch in different water bodies, but may deposit half-siblings in the same pool as tadpoles from an earlier clutch. The likelihood of tadpole cannibalism is high, but it raises the odds of survival for at least some offspring if the frogs distribute their young across multiple nurseries.

I learn that poison frogs belong to the superfamily Dendrobatoidea, which includes nearly 250 identified species. They rainbow-range from fire-engine red through to deep indigo, solid-colored, bicolored, tricolored, speckled, splotched or graffiti-streaked. Only three species have been known to be used to poison the tips of hunting darts, but most family members are commonly called some variation of “poison,” “arrow,” and “dart” frog. Many species are non-toxic, many are not brightly colored. Some species exhibit little parental care, while others rival warm-blooded animals in their dedication to their young. The young have just as diverse a range of lifestyles as their parents—some drop from eggs directly into little pools of water, some must be piggy-backed. Some tadpoles feed on anything, some feed on only what their mothers provide. Some feed on nothing at all, squirming in the leaf litter till they develop limbs and can hop away.

Poison frogs in zoos and conservation centers and the homes of exotic pet enthusiasts hop inside glass houses, their skins radiant as orchids and yet functionally non-toxic because they’ve been raised on a diet of fruit flies—which do not produce chemical defenses that the frogs can sequester for their own use. I watch YouTube videos touring cabinet-sized terraria for captive frogs. These artificial homes are festooned with dew-touched ferns and mosses and fluorescent-lit to bring out the frogs’ colors. The frogs’ throats bib as they climb the glass and perch upon rocks and peek from within leaves. They must come to know every pebble and frond within their comfortable confines, and I wonder if they go stir crazy not having a larger world to explore.

It is from captive-raised Dendrobatid frogs at the National Zoological Park in Washington D.C. that scientists first isolated and identified a mysterious skin fungus, suspected of causing frog declines in the wild. Today, the chytrid fungus Batrachochytrium dendrobatidis continues its pandemic spread across the world. It will contribute to the likely extinction of nearly a third of all known amphibian species for the same reason that any organism, the world over, suffers in a world permeated by human constructs—our roads and towns, our chemical spills and airborne particulates, our sludge, our plastic, our relentless, globe-trotting footprints.

Amphibians evolved nearly 300 million years ago, before the planet’s supercontinent Pangaea broke up. Ever since, they’ve hopped and swum and slunk and climbed over tectonic shifts in terrain, diverging from ancestral modes of living to occupy spaces I could not have imagined. Now, they hunker in the brutish tatters of world changing faster than their bodies can cope with, a fungal disease merely the capstone to a life built in the margins of the human pandemic. Some of these species we’ll never know before they’re gone. Some are rescued from what remains of the wild and placed like hot-house plants in glass boxes, where they sit under ferns and wait.

“I suggest naming all the family as suggested unconscientiously by Walls [in 1994] as Jewel Frogs [for they] are indeed small forest jewels, to be respected and protected.”
-C. L. Barrio-Amorós, 2009

I bring the four oldest—largest—of my tadpoles indoors because I want to watch their metamorphosis first-hand. On the advice of a pet forum, I place a potsherd and a couple of tan-dry leaves half-submerged in their cups, for them to climb onto when their limbs are full-formed. The tadpoles dash under cover when I shine lights to photograph them. When they’re at ease, they practice moving their legs, first one after the other as if stress-testing their new muscles, then both legs in sync. Unlike the leg buds, which burst from the base of the tail, the arms remain enclosed within the body while they’re developing. Their elbows jut from the sides, like the tadpoles have swallowed hangers. They look ungainly—creatures sheathed in the wrong skins, trying to burst free.

There’s a part of me that grows sentimental as these four tadpole faces take on the froggish contours of their lives to come. I make the mistake of naming them. Primo, first and fastest to hit his developmental milestones. Tummy, fattest of the four, who seems to want to eat even though her entire digestive tract is rebuilding itself during metamorphosis. Timid Bubbles, who hides under a leaf with just her head poking through the water’s surface, blowing a chain of bubbles along the leaf’s edge. And Bob, who doesn’t bob, but just lacks discernible personality in comparison to his cohort.

There’s a brief moment after their arms emerge that my tadpoles resemble salamanders or newts. But their tails deflate rapidly after this stage, absorbing vital nutrients back into their bodies. They keep their heads above water. When the light catches them just right, I can see the pinprick of a flickering nostril. From what I’ve read, I know the froglets will make exploratory jumps outside their nursery pools in the first days after metamorphosis. I keep their little cups inside a large plastic box with a loose-weave towel draped over it, so that even if they do hop out, they won’t get lost in the house.

Primo is the first froglet I find clinging to the inner wall of the plastic box, magnificent as his father and the size of a peanut.

I’ve read enough about D. auratus frogs to concoct the wildest of plans. What if my house was their terrarium? Here on Ancon, we keep all our windows open for cross breezes, but the humid air is often still between storms. There’s no essential difference between the climate outside and indoors. I could fill my home with plants for cover and shallow water dishes for hydration. I did not want to breed fruit flies, but I could spike the house with little drops of sugar water—the tiny ghost ants that make their homes within the walls are excellent foragers, and I could bait the area around the froglets’ hideouts to make sure they’d find easy prey. I could erect climbing branches to overhead perches. I could stop sweeping, and let leaf litter blow in through the windows and collect under the bookshelves and in the corners of the living room.

The small part of me that thinks with sense rescues the froglets from this fate. I take them outside in a shallow Styrofoam tray full of leaf litter and a bit of water. I tilt a flower pot over the tray to provide the froglets a bit of cover. Primo leaves the nest first. After he’s gone, I don’t speak for a few hours, devastated for reasons I cannot articulate. Inside the screened porch, countless nameless tadpoles continue to flicker and feed in half-empty white party cups.

“The most efficient way to maintain an accurate mental map of useful deposition sites would be to use spatial memory in a flexible manner...”
Liu et al, 2016

At the University of North Carolina, Chapel Hill, in the sterile, standardized confines of a two-armed maze experiment, green and black poison frogs used visual cues to figure out the correct exit to shelter. When the exit was reversed, the frogs modified their behavior to solve the maze again. In a study led by researchers Yuxiang Liu and Sabrina Burmeister, the maze exit was reversed five times—the frogs needed fewer trials to figure out the correct exit after each reversal, the sort of learned flexibility previously only associated with mammals and birds.

This may be the first time such “advanced cognitive ability” has been experimentally documented in amphibians. I wonder, if we’d known sooner, would we have cared more about their fates? You cannot watch a poison frog in the wild for any length of time without beginning to suspect that its headspace is somewhere several hops ahead of its current physical location. It pauses to think. It detours to investigate. It remembers and learns. I might have gone my entire life unaware of the rich inner lives of these animals had it not been for the fact that my world, at this moment, coincidentally overlaps with theirs.

We humans, in general, do not worry about our extinction, even though we’re the direct cause of the planet’s sixth mass extinction. Forget the abstract specter of this loss. We will not live long enough to feel its millennia-spanning repercussions. We live sanitized, minimalist lives, familiar only with the species that coexist with us—house cockroaches, house flies, house mice, cats, dogs, sparrows, pigeons, mosquitoes, fleas, lice, and the microbes nested within.

We are cosmopolitans, easy to transport, easy to unpack and wedge into newfound earths. From here we spread, block by block, avenue by avenue, bringing orderly uniformity to local universes that were once alien to us, their natural histories forged out of the particular demands of the minerals underfoot and the patterns of clouds circling above. Gone are the creatures of those places, and here to stay are the ones we brought with us to replace them, the ones we call pestilence, the ones we wish to eradicate, the ones so adept, so opportune, so common.

And perhaps this is why I’m so enthralled by the green and black poison frog. Against great odds, it persists in this new-formed world I live in, where skyscrapers sprout along the shoreline, where roads climb into hilltop forests, where ships sail over land. There are some two hundred amphibian species in Panama, and many are endangered, many nearly extinct. The known range of Adinobates geminisae, a tiny red poison frog discovered in 2014, could be obscured by pricking a map of Panama with a thumbtack. Craugastor evanesco, the “vanishing” robber frog, was so named because it had gone extinct in its local region by the time it was described in scientific literature. The Panamanian golden frog, Atelopus zeteki, is a national treasure and icon for bygone natural heritage—it has not lived in the wild since 2009. For now, these and more species exist only in captivity—maintained in zoos and conservation centers like the Panama Amphibian Rescue and Conservation Project—waiting for a chance to be reintroduced to the wild, once we are no longer a threat to them.

The IUCN lists Dendrobates auratus frogs as a species of least concern. They are common frogs, for this part of the world. Widely distributed and, by serendipitous chance, pre-selected for coexistence with humans because their lives are interstitial, improvisational, opportunistic. They’ll portage their young into trees, they’ll carry them into trash heaps, anywhere that rainwater collects. I have the privilege of living in a part of the city not so razed to bare rock and raised concrete, not so given over to grass islands and ornamental palms, to Pekinese dogs and feral cats, to potted figs and caged parakeets, that I can pretend, when I stare into the trees from my back patio, that I belong, amphibious, to both the natural world and the constructed one.

I have unanswerable questions. Who knows who discarded that old bean can in my backyard? Who knows how many cans I’ve emptied and sent to the landfill myself? Who can map their footprint on the earth and say they are not culpable for countless unnecessary deaths? How can I express, amid everything that has gone wrong, my gratitude to a frog that looked inside a piece of junk and still found the world half-full?