Antipode – Chapter 24
Frogs in Paradise
Antipode is a true account of my experiences while doing research in Madagascar from 1993 – 1999; it was published by St. Martin’s Press in 2001. We started with the Introduction, and here are all of the chapters posted thus far.
The beautiful little yellow and blue frogs that I had been tracking for so many months seemed largely oblivious to my presence. They did not yearn to be studied, or known. That desire lay wholly in me. When I went out on a hot dry morning, or a torrentially wet morning, and could not find male Z7 hopping around the edges of the bamboo stand, looking for an opportunity, or female B4, swollen with eggs, even though I had seen her the day before, I was disappointed. When I did not go out on a pale blue morning after a night of rain, because I was in town getting provisions, though I knew the weather was perfect for frogs, they were not disappointed. They did not need me.
And yet I put together their story, in pieces, with several reversals, in fits and starts. There are still holes in that story, to be sure, but there are threads of logical continuity between most of what I came to understand about these frogs, and these threads hold the narrative together in a cohesive mass. Before this work, science knew essentially nothing about these frogs. Now we have a set of ideas and hypotheses, some tested, some not. Hopefully, their behavior remains largely unchanged whether scientists have explained it or not. But, as physics has taught us, just the act of observation affects the outcome of any event. Nobody can know precisely what nature looks like when there’s no one around to watch.
Mantella laevigata are social animals. Being brightly colored and poisonous, they’re relatively free of predators, which allows them to be active during the day, when color-seeing, visually-oriented predators, such as most birds, are awake and hunting. Jessica and I did see one predation by a zonosaur. We also saw an attempted predation on a Mantella by a boa. Two males were simultaneously trying to court a female. She was hopping away from them, when the snake lunged at her from under the leaf litter and grabbed her in his mouth. The males scattered. The boa held her in its mouth, sometimes appearing to chew, but after twenty minutes it released her. The next day the snake, who had lived in that spot for several weeks, was gone, never to return. The frog, on the other hand, though bloodied and bitten after the event, went on to care for her offspring.
Yes, these frogs give maternal care. There is so much complexity in their social system. I am describing here but a thin slice of what I know, and even what I know is probably but a sliver of what is true. Males call from territories they defend, the best of which contain wells—broken pieces of bamboo, tree holes. Other territories are only spots on the forest floor, but males fight over these spots though they appear to be without value beyond their proximity to wells within other males’ territories. These tiny frogs can fight for hours, wrestling with each other, tumbling, chasing, yelling, the same call, over and over again, “deet-deet deet-deet deet-deet.”
“And don’t come back.”
When they are not engaged in these spectacular fights, males may call to establish their location, their ownership of a piece of territory, or to attract females. Females who are receptive—most are not, at any given moment in time—approach calling males. When a male sees a female approach, that interminable call changes, softens. Now emitting a single repeated note, spaced farther apart, “deet deet deet,” he approaches her, and rests his chin on top of her head or back—chinning, I called it. “Deet deet deet.”
“So glad you came. Please, let me show you a well you might be interested in.”
Then he leads her, oh so slowly, returning to her often to chin her again, calling all the while. He takes her to a well.
When finally they do arrive, after climbing the well together, she explores it thoroughly, alone. This, after all, is where her child will develop, if she agrees to mate with the courting male. She may reject the well. Perhaps it is too acid, or not acid enough (they actually prefer extremely acid wells, I found to my surprise). Perhaps it is too dry, or too tall, or already contains a tadpole, which she tries to avoid. Probably it will not contain other species of frogs, or the parasites that prey on Mantella eggs, for the male has already discriminated against such wells. Male and female alike are trying to find the best spot for their offspring to develop, although their interests—that of male and female, the prospective parents—are not entirely the same.
If the female rejects the well, the courtship begins again, with chinning and leading and calling. “Deet deet deet.”
“I have another, you’ll like it better, really.”
Often the courtship dissolves at this point, the female losing interest in a male who took her to a well she didn’t like. Even more often, surprisingly, the male will abandon a courtship, to fight with another male, a male who is sneaking into his territory.
But sometimes, a courtship is successful.
The female may accept the well, and allow the male to enter it with her, and amplex her—rest on top of her in the position assumed by almost all mating frogs. If they mate, only a single egg is laid. Most frogs lay hundreds, if not thousands, of eggs in a single mating, the long strings of eggs twisting in currents, easily spotted by hungry birds or fish. Not so Mantella laevigata. These eggs are laid in protected, isolated water bodies, tiny little wells, on the inside wall above the water. The parents know who their offspring are, simply because they know where they are. With this luxury comes the ability to care for offspring, and once you are caring for offspring, it no longer makes sense to produce thousands of them, for who has the energy to take care of so many? Fewer children tends to mean more care for each of them.
Parental care is relatively rare in frogs—less than 10% of frog species take any sort of care of their offspring. Most of that care is in the rather non-interactive form of egg attendance, in which one parent stays with the eggs until they hatch into tadpoles, presumably dissuading potential predators, sometimes keeping the eggs wet, or free of fungus. Mantella fathers do engage in a sort of egg attendance, continuing to defend the territories in which their offspring are developing. But mothers do even more.
If the single egg hatches, and drops into the water as a tadpole, its needs change. As an egg, it needed to stay wet, and not get eaten, but it didn’t have to find food. Eggs don’t eat. Some species of tadpoles don’t eat either, but most do, needing to eat in order to grow and metamorphose, to become frogs. Mantella laevigata tadpoles need to eat. And what they eat, it turns out, is eggs of their own species. They are cannibals.
As a result, when a female is looking for a place to mate, she is careful not to accept a well that already has a tadpole in it, for any egg she lays in that well will probably get cannibalized by the preexisting tadpole. The male who courts her is probably the father of that tadpole, so he benefits from a courtship in that well regardless of the fate of the resultant egg. If the egg develops and hatches, as the female desires, he gains another offspring. If his tadpole eats the egg, and thus gains strength and size, that tadpole has a better chance of survival. Either way, his offspring benefit. But a female who isn’t the mother of the tadpole is unlikely to see it that way. And so there is conflict between male and female frogs.
Although there is, theoretically, conflict between mother and child, too, regarding how much care the child should receive, and for how long, the mother does want the child to survive. In this system, where tadpoles survive by cannibalizing eggs, but courting females are on the lookout for wells containing tadpoles, tadpoles may sometimes go hungry. Mothers return to wells containing their tadpoles, especially those wells which have not attracted large numbers of courtships, and feed their young. Mothers deposit unfertilized eggs for their tadpoles to eat. And the voracious tadpoles inevitably eat these eggs, sometimes beginning even before the egg is entirely laid.
All of this activity focuses on and around the wells where eggs and tadpoles develop. Males fight over wells. Females investigate wells even before they are reproductively receptive, and do so again before mating. Males cruise wells too, learning which ones have been usurped by predators, or competitors. Several other species of frogs use the same wells Mantella does. Two of these species have extended paternal care, the fathers staying with their brood as the eggs develop, and later, as the tadpoles grow as well. The larger competitor species, a flat brown frog with a pointy snout and attractive white designs on its back—Plethodontohyla notostica—not only stays with his young, but actively dissuades anyone else from getting near them. When another frog, or a person, peers into a well containing one of these protective fathers and his young, the dad emits a sharp BARKof amazing intensity. It’s hard not to keep going back for more, following the same instinct that has people watching horror films and going on roller coasters. The frog, though, is not as amused, and if continually hassled, will climb the inside of the well and bark right at your face, unfazed by the fact that the primate causing all this grief is roughly 5,000 times his size.
Frogs aren’t the only animals that use these wells. Land crabs sometimes crawl into them and stay a while. Mosquitoes lay their eggs on the filmy surface. And the snarled “worms” I had seen eating frogs eggs were actually crane-fly larvae that lived inside the wells. These worm-like larvae, which attract all the gunk of the well, and tend to tangle themselves into writhing knots, will never be the poster child for any conservation scheme. Not only are they unpleasant to look at, they are voracious predators, quickly dispatching with frog eggs unfortunate enough to share their space. But they are an integral part of this system.
These wells, used by so many members of this rich animal community, are rare. There aren’t enough of them to go around. Mantella laevigata has specific requirements for these well—no other frog species, no crane-fly larvae, full of water, high acidity…the list goes on and on. There aren’t enough wells in the forest. When I added more, in an experiment to assess if such wells really were limiting for these frogs, the frogs moved in almost overnight. Adults have plenty of food. Calling perches, water, shelter—all of those resources are abundant in these lowland rainforests of northeastern Madagascar. But wells are in short supply.
When a female of any species is choosing between mates, she might try to assess who offers a better genetic contribution to her offspring, better resources, or better paternal care. But Mantella females are focused on a single thing—the quality of the well. The male can be a highly successful male who defends broad swaths of territory, or one who doesn’t defend any territory at all, one who creeps in and sneaks matings when the territorial males aren’t paying attention, it doesn’t matter. If the well is up to her standards, she will mate with him.
It is thrilling to discover the previously unknown aspects of a distinct evolutionary lineage, a species of poison frogs that are beautiful even to those who usually find such things slimy, or repulsive. True, some aspects of field work are less stimulating than others—the laying of transects, the routine collection of water chemistry data, the iterated experiments. But there is little dissatisfaction in the actual work. I go to Madagascar to watch frogs, and never when I wake up in my tent at five in the morning do I think, damn, another day watching those animals doing the same things ceaselessly. I love watching animals behave, interpreting what they do, basing that interpretation on theory that has worked itself into my head.
This is not to say, however, that there are no risks. People hear that you’re working in the tropics, and the first thing they want to know about is the snakes. How big are they, how poisonous, how aggressive, how many people die every year. How many did I see? Did I have to fight any off with sticks? Despite the fact that I did, in fact, once come face-to-face with a fer-de-lance in Costa Rica, snakes don’t tend to be a big risk for tropical biologists. Especially not in Madagascar, where there are no, count them, zero, poisonous snakes.
Disappointed by the lack of belligerent snakes, fangs dripping with deadly poison, people begin asking about the predators. Were they any really large cats—jaguars, or perhaps lions—prowling about for their next big meal? Were the crocodiles voracious? Did anything with large teeth and a nasty attitude come my way? Anything at all?
The predominant risks are not what you think. Sure, things with sharp teeth kill people. But the abiotic forces, the water and the lightning and the vast distances that separate you from help—these are what you really have to watch out for.
On my first field season in the tropics, I was in Costa Rica with Bret, five other grad students and the esteemed biologist John Vandermeer. John soon tired of hearing our excited discussions whenever we saw the tail of a snake disappear beneath the leaf litter.
“I’m not concerned about you getting killed by snakes,” he told us. “It’s the water that will get you.” He was prescient. Part of the reason the snakes were a low risk was precisely because we were afraid of them, and were careful not to walk around without high boots on, and to never reach our hands into holes in the ground without first investigating them thoroughly by other means. Part of the reason the water was dangerous was because we had no idea what he meant. Water? A threat?
A few days after John alerted us to his fears, during that first field season in Costa Rica, Bret and I were walking across the high, sturdy bridge that ran over the river near our field site. There was a lovely swimming hole, accessible from the other side of the river, and all of us had swum in it frequently. We were done with our work for the day, work that had been particularly muddy because of all the rains we had gotten in the night, and looking forward to a refreshing dip. As we began to turn down the path to the water, a local man stopped us.
“Wait,” he advised, “look at what is coming.” We didn’t speak much Spanish at the time, and weren’t sure what he was saying. We thought it probable that he was just trying to make conversation, and we were eager to swim, so we smiled and kept going.
“No!” he urged, pointing upstream, “look.” We stood at the railing of the bridge, gazing across the wide, smooth, slow river, at the trees on either side, dripping with vines and epiphytes. It was a beautiful scene, but we had seen it before. Really, what we wanted to do was swim.
Then, before our eyes, the river began rising. In minutes the water level came up ten feet, then more. The river became urgent, sharp. Swirling eddies formed in tight deadly whirlpools, then disappeared again. The shores were completely submerged, the detritus from the hills rushing down into the floodplain. Whole trees—immense boles two, three feet in diameter—rushed by. Stuck in a whirlpool, they would spiral madly then get sucked down, shot out like a bullet far downstream. Even on the bridge we were not completely safe. A bridge once 30 feet above the water was now less than half that, and the water continued to rise. Humbled, Bret gave our savior the only thing we had—literally, the shirt off his back—and we gazed at the awesome spectacle for a few more minutes before retreating to safety. We had come within minutes of being torn apart by a raging river in the throes of a flash flood, a river we thought we knew.
Later on the same trip, the six of us, minus John, our leader, were in the dry forests of Guanacaste, in northwestern Costa Rica. Bret and I knew of a beautiful beach a day’s hike down through the parched landscape. Here the Pacific coast is not ragged and dangerous, but relatively calm, with long expanses of white sand beach, and abundant iguanas and raccoon-like coatis living at the margins of sea and forest.
We went swimming in the refreshingly cool water, but as the waves came up all but I retreated to the shore. Quickly I found myself pulled by a riptide, ever farther, and unable to surmount the looming waves that formed just in back, then just ahead of me, as land grew ever more distant. I knew, intellectually, how to deal with a riptide—swim parallel to shore, or even let it take you out a little, until it weakens, then swim parallel to escape its grasp. But with the two threats of riptide and frenzied waves growing in intensity around me, I was scared. I was swallowing water, and growing less certain of my strength as a swimmer, less certain that I knew how to escape.
Finally, feeling myself losing both strength and reason, I dove under, into the seething dark waters, swam as long as I could towards what I hoped was shore, then let myself be pushed by the churning water. I don’t know how long I was under, out of view of my friends, distanced from my own sense of self, but it seemed forever, to them and to me. I emerged near shore, able now to stand in the frothy water that still churned around me. I was safe. I had survived the trial by water that John had alluded to. Never again would I assume I knew the risks of a place, simply because I knew what dangerous animals lived there.
Lightning is another unexpected hazard in the tropics. Bret must have particularly unusual electromagnetic fields about him, for too often he has found himself unnervingly close to the location of lightning strikes. Once, when he was working on a forested hilltop in Panama, a storm that had been on the horizon began moving towards him. He covered his equipment with a tarp, put down the large antenna he was using to radio-track bats—an antenna that would have been a perfect lightning rod—and huddled by a tree to let the storm pass. Soon the storm was upon him, lightning strikes growing nearer. In an instant, searing flash, an impossibly loud CRACK landed so close everything shook with the force, and the entire forest lit up. He bolted, running down the hill toward the field station while all around him, lightning continued to strike, intolerably close. It never quite got him.
All the inhabitants of the field station were standing in the lab gazing up at the hill he had been on, when he raced in, drenched and shaking. The forest was getting pummeled, over and over again, by spears of intense, bone melting energy. He had escaped, this time. But nature is a tenacious enemy, and there is no telling when or how quickly the next electrical storm would move in with such mighty force.
In Madagascar, where there are no large land predators or poisonous snakes to worry about, it is easier to concern yourself with the sea and the lightning, the treefalls that may result from lightning strikes, the diseases that can kill if left untended, the injuries that fester interminably in the hot, wet environment of the rainforest. The overarching risk, that which affects all decisions in northeastern Madagascar, is the sheer remoteness of the place.
You would be foolish to travel to such a place without emergency evacuation insurance, something that, in theory, guarantees an airlift out to medical facilities should the need arise. But this insurance doesn’t really do you any good. At Andranobe, with no radio at all, or on Nosy Mangabe, with a radio that rarely works, there is simply no way to call for help. Even if you make it the five miles to a radio at Andranobe, or jerry-rig a communication at Nosy Mangabe, maybe there will be no boat working that can come retrieve you in your illness. If you somehow manage to get on a boat and make it back to Maroantsetra, how would you notify anyone that now is the time to collect on the promise of an emergency helicopter? The phones in Maroantsetra rarely work, and then only to access Tana. During the floods of ’97 following the hurricane, the two helicopters that landed in town had to be donated by the French government. There are no helicopters to spare in this country. And though lives are certainly saved in Tana, and even in Maroantsetra, with the locally available medical facilities, many more people die than we Westerners are comfortable with. The nearest reliable emergency room is Nairobi—itself a risk, as the blood stores are tainted. Most people try to get to Paris. Arranging for all of those legs of an impossibly long voyage while suffering from a health situation that puts you at risk of dying—it isn’t particularly plausible. The time necessary to get you out of an emergency situation to safety is what will kill you.
Working in Madagascar, the research itself is rich and rewarding, the risks stranger and more hidden than you might expect, but the benefits of such a life aren’t what you might think either. Certainly my raison d’être in Madagascar was to study frogs, to understand a life form not previously known. But this did not fully explain why I was there. It was an excuse to tweak my world, turn it on its head. It is so easy to grow complacent in the comforts of the developed world, to simultaneously grow dependent on and weary of the constant barrage of news, communication, and product. It is hard, when the comforts are close at hand, to willingly remove yourself from their reach, even for a day, much less a lifetime. And it is sometimes surprising to remember that most of the world’s peoples live without these accoutrements for their entire lives. But strip yourself of the ability to order in or dial up or buy now or turn it on, and life is laid bare. The essentials become clear, as do the luxuries that bring particular joy to your life. I need to buy rice, find clean water to drink, wash my clothes, keep dry enough not to mold from the inside. I want to be able to read books, sit in a comfy chair, have time to think. Immersed in Western culture, it’s easy to mistake want for need, and ease of acquisition for desire. Do I want to check my Email five times a day, or is it a strange compulsion that arises only when I can, and am searching for meaning in a life stripped of the urgency of cooking over a charcoal fire, or taking advantage of a hot afternoon to dry out a tent?
Then there is the realization, over and over again, that people are the same everywhere. No matter the culture, there are good people and bad, and finding the good in another culture opens doors of understanding and good will. To find yourself being “other” in a society, when in your own you have always blended in, forces an investigation of the xenophobia in all of us. I can believe that all people, regardless of origin or skin color, are equally valid and valuable, but I can’t have a clue what it feels like to live as an African-American in the United States until, perhaps, I have lived as vazaha in Madagascar. Some people accepted me, some people never would, and the vast middle regarded me with some skepticism regardless of what I did. As unprecedented and difficult as that was for me, I had an out. My life as other was finite, for I was going home someday. I will never know what it feels like to have no choice in the matter.
My memories of Madagascar are a series of snapshots, frozen in time. Much of the hardship of daily life is erased from these, replaced with images of fisher people with mangos, little boys curious about language, brightly colored frogs courting and singing. I remember the sweet smell of cloves wafting through camp, and standing under a waterfall stunning in its strength and glory, and listening to the forest wake up, the ruffed lemurs cackling as the sun warmed their furry bellies high in the trees. The frogs didn’t care if I came or not, if I sat among them on my little three legged stool and studied their every move. But I did. For in starry-eyed retrospect, wiping clean the frustrations and disappointments, these were frogs in paradise.
Next week: Epilogue
I'm very happy you surfaced and survived the boat accident so you could transport me to the jungle. The frogs are fascinating!
"Nobody can know precisely what nature looks like when there’s no one around to watch."
Yes, and when Stephen Budniansky says "When we look at nature, we are only looking at the survivors" I have to ask myself, how do we know when we've seen everything?