For the Love of Lemurs

To her delight, social worker-turned-scientist Patricia Wright has found the mischievous Madagascar primates to be astonishingly complex

A verreaux's sifaka lemur can jump 30 feet (Frans Lanting)
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Given her sense of identification with female leadership among lemurs, Wright was shocked when she learned recently that her greater bamboo lemurs have a dark secret. “Listen to them!” Wright cries out one morning on Trail W, where her lemurs are violently shredding the bark from towering bamboo stems. “They talk all the time. They crack open bamboo all the time. How in the world could I have had such a hard time following them for so many years?”

Female greater bamboo lemurs spend much of their day chewing through the hard outer surface of giant bamboo stems, till the pieces of stripped bark hang down like broken sticks of dry spaghetti. What the lemurs want is the edible pith, which looks about as appetizing as rolled vinyl. It also contains stinging hairs and, in young shoots, a small jolt of cyanide. Having adapted to digest that poison lets the species exploit bamboo, an otherwise underutilized resource.

“The female is using her teeth to open these bamboo culms, really working—and the male isn’t there,” says Wright. “And all of a sudden you hear this big squabbling noise, and the male appears just as she opens up the bamboo, and he displaces her and takes it from her!” The thought leaves her aghast. “This is unheard of in Madagascar! Then he moves on and takes away the bamboo from the next female.”

At first, Wright and graduate student Chia Tan thought they were simply seeing bad behavior by one beastly male. Then a new male came in and did the same thing, forcing the researchers to contemplate the possibility that the greater bamboo lemur may be the only male-dominated lemur species. Wright and Tan theorize that the females cannot hear anything over the racket of their own chewing; they need the male to patrol the perimeter and alert them to danger. But they pay the price at feeding time. “It’s beautiful to watch,” says Wright, “it’s horrible to watch.”

In another corner of the park, sifaka group three is feeding in a rahiaka tree, and Wright is talking about Mother Blue, the lemur for whom she has always felt the deepest empathy. During the first decade of Wright’s work at Ranomafana, Mother Blue gave birth every other year, the normal pattern for sifakas. She raised two of her offspring to maturity, a good success rate for a lemur. Though female lemurs can live for more than 30 years, they produce relatively few offspring, most of which die young.

Mother Blue, says Wright, was not just a good mother but also a loving companion to her mate Old Red. “They groomed each other, they sat next to each other, they cared about each other.” But Old Red eventually disappeared, and in July 1996, says Wright, a new female arrived in group one. Lemurs are by and large peaceful, but they still display the usual primate fixations on rank and reproductive opportunity. Male interlopers sometimes kill infants to bring their mothers back into mating condition. Female newcomers may also kill babies, to drive a rival mother out of a territory. Soon after the new female appeared, Mother Blue’s newborn vanished. Then Mother Blue herself went into exile.

“I arrived a few months later and saw Mother Blue on the border between group one and group two, just sitting there looking depressed,” says Wright. “I thought, this is what happens to old females. They get taken over by young females and just die.”

Despite continuing deforestation elsewhere in Madagascar, satellite photographs indicate that Ranomafana remains intact. Partly because of the success there, Madagascar now has 18 national parks. President Marc Ravalomanana has pledged to triple the amount of open space under government protection by 2008. Wright, among her other ambitions, hopes to establish a wildlife corridor stretching 90 miles south from Ranomafana. She also still yearns to find out what makes different species tick.

At the rahiaka tree, for instance, Earthwatch volunteers are keeping track of the lemurs as they feed on a reddish fruit about the size of an acorn. The edible part, a rock-hard seed, is buried in a ball of gluey latex inside a tough, leathery husk. It doesn’t seem to discourage the lemurs. One of them hangs languidly off a branch, pulling fruit after fruit into its mouth, which is rimmed white with latex. The sound of seeds being crunched is audible on the ground, where Wright watches with evident satisfaction.

It turns out Wright was mistaken about Mother Blue. The old female lemur did not simply go into exile and die. Instead, she has moved into group three and taken up with Pale Male’s son, Purple Haze, a decidedly younger male. The two of them have a 3-year-old, also feeding in the tree, and a 1-year-old, roaming nearby. Wright is delighted with the way things have worked out. (She has also taken up with another male: her second husband, Jukka Jernvall, a Finnish biologist.)

About Richard Conniff
Richard Conniff

Richard Conniff, a Smithsonian contributor since 1982, is the author of seven books about human and animal behavior.

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