The fossa is a “killing machine,” according to biologist Luke Dollar. It will go after the biggest prey it can sink its teeth into, even dominant female lemurs. “That takes guts,’’ Dollar says. “ ‘You’re my body weight, but I’m going to attack and eat you.’ ’’

We are hiking in silence, at a fast clip, up a nearly vertical ridge in Madagascar's Ampijoroa National Park. It's seven o'clock on a winter morning, but the temperature is already settling into the high 90s--a wall of heat through which we struggle to carry our gear and gain some traction from the sandy soil. Overhead, stands of baobab and rosewood trees rise more than 60 feet into the sky, opening out into an airy, inviting canopy. Down here, the forest is a tangle of lianas, shrubs, and saplings. We are scratched and bruised and desperate for a sign--any sign--of our quarry.

For a week now we have hiked more than 20 miles a day, frequently off trail, in search of the island’s most elusive animal: a carnivore little known to science and unknown to most of the world. The Malagasy people call it a fossa (pronounced foo-sa) and tell bedtime stories of it snatching babies from cribs, extinguishing campfires, and killing coopfuls of chickens with its flatulence alone. “Be good,” they tell their children, “or the fossa will get you.” (Worse, you may be reincarnated as one.) Scientists call it Cryptoprocta ferox, with taxonomic exactitude, but they know little about it—many have spent years in Madagascar without even glimpsing the animal. Only one thing is certain: On an island often described as an Eden, distinctly lacking in natural violence, the fossa is a striking anomaly. Though it weighs less than a cocker spaniel, it may be the deadliest carnivore, pound for pound, on the planet.


Today, as usual, Luke Dollar is leading our team. And as usual he is frustrated. A graduate student in ecology at the University of Tennessee, Dollar has radio-collared two fossa already, despite that they have a hunting range of 12 miles and his telemetry equipment has a range of barely two miles in this forest. Sometimes, when he holds the rubbery antenna aloft, loud promising tocks come over the receiver. But deep ravines and sharp, impassable ridges block transmission at crucial moments, and the best signals invariably turn to static.

Madagascar has six kinds of forests, all of  them home to the fossa, and other habitats nearly as spectacular. On the savanna above his base camp, for instance, Luke Dollar scares up locusts by the millions.

Still, this morning feels different. Last night, something attacked one of the 25 traps Dollar set up around camp, mutilating one of the live chickens he uses as bait. Although the attacker got away, shreds of evidence from our daily tracking suggest it was a young female named Tasha. She will probably return. Now, as we approach the traps and the telemetry signal grows more insistent, Dollar quietly gives a high five to Pierrot, his Malagasy assistant. Pierrot eventually splits off to check the traps, but we continue upward, following Dollar’s instincts as much as the signal.

Five minutes later, pulses racing from exertion and anticipation, we stand stock-still at the crossroads of two trails at the heart of the forest. Seventy yards away, in the dim light of the deep woods, a shape as long and low and dark as the shadows emerges. For just a moment, it hesitates at the forest’s edge, peering in either direction. Then it floats across the open path and disappears like smoke.

Dollar first heard of the fossa in 1994, while working as a research assistant in the Ranomafana rain forest in southeastern Madagascar. He was tracking some red-bellied lemurs, he remembers, when his telemetry equipment picked up an odd signal. Its frequency suggested that it was coming from a collar worn by a lemur named Stanzi, but Stanzi’s collar hadn’t been working in years. Intrigued, Dollar tracked the signal to its source, stopping where the signal seemed to be strongest. There on the ground, amid a few clumps of lemur fur and carnivore scat, he found the shredded remains of Stanzi’s collar. Apparently, its battery wires had been reconnected by a powerful chomp. When the Malagasy field assistants saw this, they whispered only one word: “Fossa.’’

From that moment on, Dollar dedicated himself to the study and conservation of an animal he had never seen. He began by returning to the United States and thumbing through every animal encyclopedia and wildlife journal he could find. The fossa was first seen by Westerners in 1833, but they noticed little about it other than its taste for blood. In 1874, Johnson’s Natural History noted that the fossa is “ferocious and sanguinary in the highest degree.” Twenty-three years later, The Antananarivo Annual went even further: “When at large, [the fossa] is justly dreaded, and from its mode of attack, appears to be like an immense Weasel, but preying on the largest animals, Wild hogs and even Oxen.”

After that, for nearly a century, biologists kept mum. In the 1970s, a reclusive Frenchman named Roland Albignac wrote a few monographs about captive fossa and observed them in the wild. Today, there are 55 fossa in captivity worldwide, and a zoo in Duisburg, Germany, has bred 13 of the animals. But biologists have yet to sort out some basic issues of fossa gender (see “Wild Thing,” page TK), and the animal’s behavior in the wild is even more of a mystery. In the United States, only the San Diego and the San Antonio zoos have fossa in their collection.

WILD THING

Nearly a century ago, Swedish naturalist Einar Lonnberg managed a difficult feat: He made the fossa even more mysterious. Some females of the species, Lonnberg noted, have a clitoris so large that it could be taken for a penis, and a pair of genital bumps that could pass for a scrotum.

Although genital mimicry is rare in the animal world, female spotted hyenas have sham scrotums and pseudo penises so convincing that even experts have a hard time distinguishing males from females. Hyena society is both extremely hierarchical and extremely competitive in regard to feeding. Sham male genitals may allow females to establish rank during the ritualized hyena greeting ceremony—and help them fight to keep it, thanks to extra male hormones coursing through their systems.

Luke Dollar, who has never seen a fossa with genital mimicry, thinks the feature in this nonsocial mammal could have less to do with necessity than ancestry. As animals grow they often reveal their evolutionary lineage in passing. Human fetuses, for example, show temporary gill slits and tails during development. In fossa, pseudopenises may only appear in infants, an ephemeral reminder of their relation to hyenas: The two species shared a common ancestor some 20 million years ago. That would explain why Dollar, who has caught only adult and subadult female fossa, has never seen the trait.

It’s an appealing hypothesis, but not without its own problems. Last June, at the San Antonio Zoo, a pair of fossa gave birth to three offspring, one male and two females. The females showed no sign of the mimicry. —Vicki Croke

The prevailing ignorance is somewhat understandable. Tracking carnivores is tough in any setting, and in the tangled forests of Madagascar it’s close to impossible. Even short trips through the forest leave you slashed by sharp branches [WHAT SORTS?] and burned by “itchy vines’’ that coil around human limbs. The air is full of sweat bees, lapping up precious moisture from exposed skin. The rivers and lakes are full of parasites and 14-foot Nile crocodiles, waiting patiently. And the ground may be covered in terrestrial leeches. Medical care is primitive, cholera outbreaks occur occasionally, and malaria, borne by chloroquine-resistant mosquitoes, is rampant.

Full text of this article appears in Discover magazine.





For information on how to help Luke Dollar set fossa traps and operate radio-tracking equipment in Madagascar, see www.earthwatch.org.