Could You Repeat That, Pink Face?
Since daybreak he has been scanning the treetops for the creatures that move as if by pogo stick and look as if they wear white fur coats and face masks.
It is after 2 p.m. and the dense, hilly rain forest has yet to give primatologist Erik Patel a glimpse of Propithecus candidus, the rare monkey-like lemur known as the silky sifaka. It is one of the world’s 25 most endangered primates. Fewer than 1,000 silky sifakas are thought to exist, all of them in this rugged patch of Madagascar.
Finally, a guide working with him spots a flash of white deep in a ravine. Within minutes Patel skitters and slides down the root-covered slope, where he hears a familiar sound: the sneeze-like “zzuss” call the animals emit when alarmed.
“It’s Pink Face,” he says, wiping sweat from his forehead. “I know it’s him.”
Patel, 35, is a scientific pioneer, the planet’s foremost expert on the silky sifaka. Until 2001, when he began work on a doctorate at Cornell University, the sum of knowledge about these animals was as fleeting as their ghost-like visage. He chose this path precisely because he would have to blaze it.
Patel and Africa’s dozens of other animal researchers represent the newest chapter in scientific discovery. Using a wide variety of methods and approaches, they are continuing a tradition made famous by chimpanzee expert Jane Goodall and the late Dian Fossey, who studied and lived among mountain gorillas for nearly 20 years.
The work can be lonely and tedious. During his months in the forest, Patel favored his work over his health and his personal life. But he is on a mission, not unlike earlier explorers who, having mapped the coastline of an unknown shore, ventured into the interior without being certain of what they would find.
Over the last four years, Patel has spent 14 1/2 months camping in this forest. He is back for a few weeks to observe Pink Face and the others in this community of six lemurs. He hopes new data will shed more light on how the animals communicate, information that may one day yield clues about how speech evolved in humans, the lemur’s distant cousins.
He feels a sense of urgency. Despite an increase in conservation efforts, including Patel’s, no one knows how much longer the silky sifakas can survive persistent hunting and deforestation. They may need him as much as he needs them.
No one can mistake these animals for any other kind of lemur. Only the silky sifakas have fluffy white fur covering their body, everything but the face, which is slate-gray or pinkish. Their eyes are reddish-orange.
They have been dubbed flying angels for the way they soar from tree to tree. In reality, they use their powerful legs and fingerlike toes to grasp a tree trunk or branch and quickly push off to the next one, as much as 10 feet away.
They’ve had lots of practice: Lemurs may have been eating tree leaves and exploring the forest canopy for 50 million years.
How they got here remains a mystery. Madagascar, along with India, split off from Africa about 125 million years ago, and parted from India 88 million years ago -- before lemurs existed -- to take its place as the planet’s fourth-largest island.
One theory holds that a storm washed some lemurs off the coast of Africa and that some of the animals floated on vegetation before chancing on Madagascar.
The island’s long isolation meant that most of its plants and animals evolved separately from the wider world. Biologists estimate that eight in 10 of its species -- plants as well as animals, including birds, reptiles and frogs -- are found nowhere else, an astonishing rate of uniqueness. People arrived 2,000 years ago, probably from Indonesia, making this one of the last-settled major land masses on Earth.
The most striking example of the island’s species diversity may be the lemurs.
Taxonomists group them into 70 species and subspecies (humans are known to have driven 17 species to extinction), and all occur naturally only in this country. The rise of faster, stronger monkeys on mainland Africa may have killed off the ancestors of lemurs there, but monkeys never reached this island.
Scientists generally consider lemurs, which have the smallest brains among primates, to be less intelligent than relatives such as baboons, chimpanzees, apes and various monkeys. Yet their parallel evolution has made lemurs different in key ways and therefore interesting to scientists looking for broad-based models to explain the evolution of primates.
For instance, males reign across all nonhuman primate species except, apparently, in some lemur species that show evidence of female dominance.
The study of lemurs is relatively young, particularly when it comes to species found in forbidding terrain, and few live in tougher territory for researchers than the mountain-dwelling silky sifaka.
By the late 1990s, before silky sifakas were elevated from subspecies to species, little was known about them. In his brief discussion of them, Nick Garbutt, in his 1999 book, “Mammals of Madagascar,” noted that their primary habitat was mountain rain forest above 2,600 feet, that they weighed 11 to 13 pounds and that adults measured 3 to 3 1/2 feet, half of it in the form of a fluffy tail.
In 2000, the State University of New York’s Patricia Wright spent a couple of weeks in Marojejy darting animals to get blood samples and basic measurements. But no one had done a full-fledged study until the arrival in 2001 of an American doctoral student who once thought he would become a stockbroker.
For the first six weeks, the silkies hurried away from Patel and his research assistants. That was no surprise: Until then, most humans who approached probably meant to kill them.
Gradually, though, the animals got used to Patel and his team, which included up to four American or British field assistants, plus Malagasy guides hired to help track the animals from dawn to dusk.
Patel’s second trip to Marojejy was his longest, from July 2002 to June 2003, including the rainy season. Torrential downpours transformed streams into rivers that could be crossed only with a rope. Creeping through the forest meant slipping and sliding. Clothing never dried.
At low points he thought about a girlfriend he might have married if he had not chosen the silkies over her. Myriad health maladies -- boils, infections, leeches -- didn’t help morale.
Despite periodic trips to the city of Sambava to enter data into a computer, a fog would blanket his brain. Patel recalls thinking it had been some time since he had said much besides, “Can you pass the beans?” or “Want to play cards?”
The silkies provided mental stimulation. On the move, they could shinny down one tree, jump to another and scurry straight up 50 or 60 feet. Sometimes they would drop close to the forest floor and observe their observer. Patel recalls a young one touching him while he was videotaping the group.
Sifakas are a large category of lemurs, resembling a cross between a bear, a monkey and a raccoon. They remind Patel of cats, with one exception: Pink Face, the twentysomething male. Patel came to think of him as a fellow man.
“The connection between Erik and Pink Face was weird,” says Claire Santorelli, his chief field research assistant. “It was really strong. I’m sure he used to speak to him, ask him for advice.”
Patel and his team weren’t there just to gaze at the animals. They devoted hours to writing down what the silkies did. They determined that the lemurs mostly rest (45% of the time) and forage for leaves and fruit seeds (22%). Play, grooming and other social behaviors account for 16% of their day.
Although Patel did not see consistent female dominance, females sometimes bit or slapped males during feeding, prompting submissive squeaks from the males.
Patel also made the most complete audio recordings of lemurs in the wild. Silkies possess a fairly small vocal repertoire -- including a howl, a youp, an aerial roar, a purr, a chatter-squeal (emitted by the victims of rare aggression), as well as mums, hums and the zzuss alarm call.
But they are fairly talkative, Patel says; he has amassed a catalog of 600 zzuss calls alone. Analysis at Cornell’s lab revealed an interesting finding: Though male and female lemurs have roughly the same body size, the acoustical makeup of their zzuss calls differs by sex, suggesting variations in the vocal chords or neurological differences.
Why might that matter? Zzuss is the call made when an individual silky sifaka, setting out on its own, encounters a new group of silkies. Whether that animal can join the group may depend on the animal’s sex -- subtly announced by the zzuss -- , and the ratio of males to females in the group.
Patel documented as well the threats to the silkies, mainly from people. From villagers outside the park he learned that Madagascar’s well-to-do enjoyed the taste of lemur as a delicacy or “picnic food” and hired unemployed villagers to hunt them.
Pink Face isn’t the only silkie with a name. Patel points out Black Hands, a 3-year-old with curious eyes. “I knew BH when she was this big,” he says, holding his hands a foot apart. “She’s a big girl now, acting like a typical juvenile, falling out of trees.”
Through the dense vegetation he spies Antenna Female (named for the radio collar she once had), Black Cap (for the coloration atop his head) and Black Face Pink Hands (a second female), or BP. But he is most interested in a sixth silky he cannot find, a young one born in June 2004.
Infant mortality is high, another danger to the species’ longevity. Since there may be fewer than a thousand left -- all in the wild -- every one counts.
The next day, Patel sees the infant. Relieved, he can focus on his primary mission: to collect soft hums and mums thought to be “we’re about to move” calls. He wants to analyze them to see whether, like the zzuss call, there are gender or individual differences.
One day is wasted when the animals never venture far from a raging river, which obscures their voices. The next morning, though, he captures clear mums from Pink Face and three others.
Moments later, the group zooms into the canopy for a snooze, something they do five times a day for 15 minutes to three hours. Some stretch their bodies into hammock shapes, others nap hunched over. One has the munchies and snacks on leaves.
Fifty feet below, Patel sits on a wet log, staring up with binoculars in one hand, microphone in the other. The silkies show no sign of moving. Patel passes the time by coining a name for the young one -- Black Face.
Two hours later, at 12:30, the animals still have not moved. But a few minutes after that, something even better happens.
BP rapidly descends a tree trunk like a firefighter sliding down a pole. She parks herself on a branch about 15 feet off the ground and 20 feet from Patel. She looks around and scratches absent-mindedly. All the while, she goes “Mum, mum, mum.”
Patel records every sound.
