The Rarest of the Rare: Vanishing Animals, Timeless Worlds

by Diane Ackerman

  “This is the most dangerous part of our job,” Ben says, grinning, as we drive north along the two-lane highway that has opened the Mata Atlantica up to civilization. Cars and trucks typically speed four abreast, use the road shoulders as passing lanes, and often lose their axles in yard-deep potholes. Young boys stand along the roadway, selling wads of dried, pressed bananas. We pass dozens of ceramics plants. Terra-cotta roof tiles are a big industry in this part of Brazil; the factories are fueled by rain forest trees.

  In time, the strip of fast-food joints, barbecue restaurants, and businesses gives way to rangy farmlands and forested knolls. Ahead we see a mountain range—the edge of the Atlantic coastal forest, the fragile margin of a continent. It is against Brazilian law to cut down rain forest at the top of a mountain because the trees prevent terrible erosion and mud slides. The mountaintop forests remain to protect the farmers, but, inadvertently, they have saved the forest creatures in small floating islands of vegetation. At a sign marked RESERVA BIOLÓGICA POÇO DAS ANTAS, we turn onto a dirt road and follow it for twenty minutes through farmland, swamp, and then forest, to a palm-lined drive and a large white stucco house.

  Once a goat barn, the house was rebuilt by the first researchers. Now it looks large and inviting, with a swelling purple bougainvillea at the front steps, a herb garden, a barbecue pit, and bread-fruit, lime, and banana trees. Inside, a small kitchen opens onto a dining room dominated by a long table, whose top is an irregular slab of local wood polished to a high gloss. Two small bedrooms, each with four bunk beds, serve as men’s and women’s dorms. A toilet and shower stall are across the hall. Most people gather on the open-sided back porch, where four black car seats have been arranged as couches. Clotheslines hang above them. Against the wall, a blackboard gives the week’s schedule, and beside that a worktable holds tools, monkey feeders, and miscellaneous fixings. A pegboard stores raincoats, with wet mud-clotted boots arranged neatly below. Smells of mildew, ripe bananas, dog-food-like “Monkey Diet,” free-roaming chickens, car exhaust, and wild-flowers mix in the air.

  Work starts right away. Our monkeys need temporary lodgings. A family of wild golden lion tamarins would normally sleep huddled together in a tree hole or a thick nest of vines. Three large cages nestled in the forest at our front door will be their halfway houses. We begin by filling the cages with branches, bromeliads, and lengths of bamboo. Then we hang a water bowl from one branch and small partially peeled bananas from another. A few shoebox-shaped wire traps also hold bananas. If the monkeys can be habituated to the traps, they’ll be easier to catch once they’re in the wild. Then we fit each cage with a “nest box,” a large blue-and-white Igloo ice chest that has been specially adapted for the monkeys. Tamarins prefer duplex homes, to give them a little variety and to protect them against predators. So the nest boxes have been divided into two rooms, an upper and a lower, with an almond-shaped door leading into the top story. A tamarin that wants privacy can generally find it, and if an ocelot reaches into the top of the nest, the tamarins can dash to the bottom.

  As we arrange all the bits and pieces of the tamarins’ new world, the cage starts to look like one of Joseph Cornell’s collage boxes, or a Christmas tree minus the tree. Andrea wires the last ornament into place—a large, square feeder whose technical name is “portable micromanipulator platform.” The locals just call it a comidoro. Like an oversized scaffolding of Tinkertoys, its five plastic pipes are riddled with evenly spaced holes and filled with a variety of chopped-up fruits and chunks of the Monkey Diet. The comidoro makes it possible to feed the monkeys, but it also trains them to insinuate their long slender fingers into tight places to search for food.

  Across the compound, the monkeys quietly call to one another, and we hear their uncertain voices echoing through the yard. They’re lucky to be here. At the last minute, they were nearly left behind. This summer Chicago’s Brookfield Zoo (which has been successfully breeding tamarins for many years) sent the National Zoo a family of monkeys to return to the wild. But, when they arrived, a vet discovered that Flash, the breeding male, had a positive blood titer for a hepatitis-like virus. This wasn’t unusual—human adults often carry positive antibodies to mumps or measles, which they were exposed to as youngsters, without being able to infect anyone. So they assumed Flash was safe, but they quarantined him anyway. None of the other monkeys showed any signs of the illness. A week ago, the zoo’s pathologist positively identified the virus as one that causes hemorrhagic fever, a rodent-borne illness that can also afflict people. Rumor had it that the infected animals could be Typhoid Marys—although not appearing to be ill themselves, they might pass the virus on to others. Suppose the male died and was scavenged by rodents, which in turn were eaten by other rodents, porcupines, or oceleots, and an epidemic started that threatened the whole rain forest? How could the zoo expose the last golden lion tamarins to a plague? Three days ago, Ben decided not to risk bringing Flash. The rest of the group came—but now they need a breeding male.

  “This was a total ringer for me,” Ben says as he adjusts the wiring on the comidoro. “What to do? Well, I found a young male already in Brazil who was just coming to breeding age. He’s not ideal—we like males to have had experience in child rearing before they start their own families. But we checked his genes, to make sure there wouldn’t be too much inbreeding, and he’s a good mate for this Brookfield female.”

  At the National Zoo, a “golden lion tamarin studbook” functions as an old-fashioned family Bible, chronicling all the marriages and offspring of GLTs throughout the world. A computer check gives keepers “the coefficient of inbreeding”—a key to lineage and genetic diversity. Circumstances don’t always allow genetic mixing to take place. This is especially the case among zoo populations, where the animals can become too closely related and lose the variety needed for a strong immune system. Some wild animals—the cheetah is perhaps the best-known and saddest case—are so inbred that extinction is almost certain. Because the world’s cheetahs have identical DNA, they’re essentially clones of one another. To thrive, a species must be larger than any one individual, but with cheetahs each individual is the whole species. Any virus that can kill one of them can kill all of them. Because wild golden lion tamarins are developing a similar problem, zoos mate them carefully and even use birth control in some groups to ensure a strong bloodline.

  When the Brazilian male joins the Brookfield female and children, he’ll be a “veteran greenhorn,” a reintroduced monkey who already knows the ropes, and that will help the newcomers adapt. Already savvy to the rain forest, he’ll search out insects from twisted palm leaves, orient himself well among the branches, and be alert to predators. Although he won’t consciously teach them skills, they’ll learn faster by watching him.

  “Okay. Let’s go get the monkeys,” Ben says at last, and we fetch one of the pet kennels, carry it into the cage, and open its door. A streak of yellow, the mother leaps out uncertainly, runs to the familiar smell of the nest box, and dives in. Her four offspring follow, making high smooching sounds as they poke their heads out and eye their new surroundings. The babies look like little troll dolls with wild manes, radiant skin, rubbery faces, and round eyes black as Sen-Sen. Mother looks more like a Kabuki dancer, with slightly Oriental eyes, crepey skin, and a strong chin. As the kids creep out to explore the cage, they make steady “contact calls” that mean something like “Hey, I’m here! Where are you?” “I’m here, too. Who else is here?” One of the kids finds a banana and utters a high-pitched trill. Soon all of them are eating. The locale looks strange, but at least the family is together and there’s food and even the reassuring scent of their beds. Their lower jaws drop open to reveal sharp teeth as they bleat their long calls. Then they drag their rumps along the branches, scent-marking from chest and anal glands. A rich aroma of musk sweetens the air. Soon the cage will be completely decorated with smell—their only possession—and the new will become more familiar. Andrea whistles and chucks, and a kid chucks quiet
ly back to her.

  Returning to the porch for a second kennel, we carry Marty, a two-year-old male from the Brookfield Zoo, and give him a cage all by himself near a lime tree. In the forest, a grave tragedy happened last year. A tamarin family from Los Angeles was getting on splendidly in their new world when poachers stole the mother and father to sell as pets. This left four orphans: a young female, a young male, and a pair of twins only two months old. The older brother and sister have been raising the twins as best they can, but they mustn’t mate. So we’ll remove the brother, give Marty to the sister as a mate, and hope that he’ll adopt the younger kids and have more of his own.

  Finally, we fetch the last tamarins and release them into a third cage. This group includes a still-fertile middle-aged mother, a teenage daughter, and a younger son and daughter. They need a father. Our plan is to capture a compatible forest male for them. Such matchmaking doesn’t always work. Sometimes a betrothed pair take a real dislike to each other. But that happens rarely. A larger and philosophically more disturbing hurdle is that the animals raised in captivity have forgotten how to be monkeys.

  When zoo-born tamarins are set free in the forest they become disoriented and helpless. They lose their way in dense thickets among the thorns and the lianas. Not knowing how to feed themselves or return to their families, many starve. Would we know how to survive on the African savanna? Zoo animals have not learned how to forage, elude predators, be spatial, decipher their surroundings. Place a banana in front of them and they won’t know how to open it. Imagine having to teach a monkey how to open a banana! Most of all, they are not used to disappointment. In zoos, food arrives on schedule in easy-to-eat-from bowls or plates. In the rain forest, they must discover food—insects hiding in rolled palm leaves or under bark; fruits; small amphibians. Food moves sometimes, and comes in all sorts of shapes, and it may not be where they last found it. How do you teach a monkey not to be discouraged? They must also learn that some frogs and snakes are poisonous. Poisonous animals didn’t share their cage in the zoo. And they must learn about falling. In zoos, they ran along sturdy branches, bars, or ropes; they clung to cage wires. Never were they more than a few feet from the ground. In the rain forest, twigs may snap, slime-coated vines may send them skidding, not all branches will hold their weight, and tree canopies arch hundreds of feet above the ground. In zoos, ground means benign keepers and a safe stable world where tamarins feel secure. Yet in the wild, it’s the sky that will save them—the ground teems with jungle cats, human hunters, and other predators.

  Wild tamarins lead lives of elaborate social rituals and tribal relationships. Acrobatic and analytical, they can take the measure of a forest and map the best feeding spots. Although they sometimes fight with neighboring groups, the battles hide a secret agenda. While the adults posture and rave, the juveniles play together and check out potential mates. They really haven’t other socially sanctioned ways of meeting. It is the habit of golden lion tamarins to be monogamous and live in tight family groups, where the father helps to raise the offspring. When a daughter reaches puberty at about two years old, the mother drives her away to find her own family, so that incest won’t occur; the father does the same with a mature son. Females almost always give birth to fraternal twins, and siblings help raise one another. Large families are the rule. Touch dominates their lives; when they’re not feeding, they’re playing together or grooming one another. Separated from their family, they can die of loneliness. Ben and his colleagues have spent many years studying them. Few of the reintroduced tamarins survive—70 percent die in the first year after release. That 30 percent live is the great success story of the project.

  After we unpack and the monkeys have had time to settle into their new surroundings, we catch three tamarins in traps and carry them to the laboratory to receive radio collars. In her small cage, Jenny watches us quietly. I slide a wooden divider through the cage bars and press her against one end of the cage so that Andrea can give her an injection. Three minutes later, she tumbles asleep. Sliding my thumb and forefinger around the back of her neck, I tow her out of the cage. How soft and frail her throat feels. It is unnerving to hold the windpipe of a living thing tight enough to restrain it, but loose enough not to choke it. What delicate, just-this-side-of-deadly balance will do? As my fingers make their own decisions, I’m reminded of how many of life’s processes require complex acts of inarticulate finesse. One rarely pauses to divine how to climb a ladder, swim, cross a busy street; muscles and joints make their own small trials and revisions. Jenny is not as cognitive as I am, but her body follows its own wisdom in the same way mine does. There was a time, not far away in the shadowy past of our species, when we looked, and even thought, a lot like her. How eerie it is to cradle a previous version of yourself in your arms.

  Carrying Jenny across the room, I first set her on a scale—she weighs 630 grams—then lay her down on the worktable. Golden tufts of fur stick out between her fingers and toes, which have small round pads at the base of each claw. Her long, slender fingers were made for reaching into narrow places, where insects may lurk. I have seen lithe, graceful hands like these in paintings of Thai dancers. Stroking the dark footpads, I’m surprised to discover them soft and yielding. Sensitivity is costly. Her vulnerable soles will open a world of details to her, but at what price? Thorns, stinging ants, bees, sharp bamboo, all could be dangerous. Unlike many monkeys, GLTs don’t have prehensile tails; the long tail serves as a balance bar. On her small nose, two thin nostrils angle away from each other. A slight upside-down curve is the natural shape of her mouth, as if she were caught in a perpetual pout. Gold whiskers sprout from her chin, and a widow’s peak of canary yellow leads to a full golden mane encircling the head. Her tiny guitar-pick-shaped tongue, flicking in and out, has a deep groove down the center, where most of the taste buds lie. Golden lion tamarins give off such a pungent odor that it’s one of the ways to identify them, by depth of smell. Burying my nose in her chest, I inhale deeply the aroma of hot gingerbread mixed with drenched wheat. We jot down that her powerful smell is “average.” Andrea fits her with the radio collar, a bow tie of electronics and antenna. Then I carry her to the sink and paint her tail with black dye. Picturing the tail in four sections, we mark monkeys according to a code, which makes it easier to identify them. Because she’s the senior female, her whole tail will be black. Now Alfie begins his dentistry experiment, applying green latex to her teeth and taking an impression. What sharp canines. When I see a palate covered with ridges, I smile, because I have seen that pattern before, on dental casts of my own mouth. All primates have grooved palates. Finished with her at last, we set her back in a small cage so we can keep an eye on her until she wakes.

  Then we “process” her daughter, Maria, in just the same way. But we’re distressed to find a cut, like a small red badge, on her left shoulder. This pair, from the Columbia Zoo, has been quarreling worse than we thought.

  “As long as there’s no cut on the face, it’s okay,” Joleen says cautiously. “If there are cuts on the face, the fight’s gotten serious enough for someone to get killed, because it means that one of the animals has become passive and isn’t running away from attack.”

  At the moment, mother and daughter can’t get out of each other’s way, and we’re hoping that tomorrow, when a male arrives for mother, daughter will become more pacific, and the whole family will settle down. Then we’ll turn them loose in a fruit-laden forest. If their social bonds are sturdy and they adjust well to their new home, they should start breeding right away. In the wild, GLTs generally get pregnant once a year. But in especially rainy years, when fruit is plentiful, they sometimes get pregnant twice. Each time they give birth to fraternal twins, and it’s those offspring who really master the rain forest. Reintroduced monkeys are typical immigrants, plagued by the usual array of immigrant problems. They don’t adapt perfectly because there’s too much that’s new—sounds, foods, housing, predators, climate, disease, traffic patterns, educational n
eeds. Their old-country dialect of habit and action doesn’t quite work in this teeming new world. But their offspring will fit into this magical realm as perfectly as an incantation. The first generation born in a country belongs to it.

  At five forty-five the following morning, the rooster begins loudly crowing, although gagging would be a more accurate description of the noise, since he sounds as if he’s choking on lengths of flannel. The room is black as a mine shaft. After the fortieth crow, I stop counting and swing my foot out of bed, halting just in time as I recall that I’m in the top part of a bunk bed. Making my way to the kitchen, I light a candle and begin the ritual of coffee—boil water, toss grounds into it, bring it fast to another boil, drag it off the flame just as it’s starting to boil over, and then drip it through a socklike cloth filter hanging from a tripod. Finally, I pour the coffee into two tall thermos bottles and help myself to a cupful. Strong, greasy, glycerin-black, Brazilian coffee packs a wallop, which sends me out to the porch as daylight is breaking. There I find Andrea and Beate, already preparing food for the monkeys.