Cara Brook is a Disease Ecologist working in the Andrew Dobson Lab at Princeton. She currently studies the great bats of Madagascar—flying foxes—and the diseases that they carry that could spill over into humans. Capturing and studying wild bats, of course, requires an ability to blend in to Malagasy culture in addition to the environment which, luckily, Cara is quite adept at.
We net and process our bats by headlamp long into the night, and my mind whirls in its sleep-deprived state. I wake in the tent, still extracting bat teeth in my dreams, and ask Yun-Yun if we remembered to release the Rousettus. Next morning, Christian shakes his head as we recount the story and pours a cup from our camp thermos. “Ampina, kafe!” he says, handing me the glass. Have another coffee!
Suffice it to say we’ve spent the past few weeks adventuring through one of the most unique and awe-inspiring landscapes I have ever encountered: Ankarana Special Reserve, where the eroding limestone karst gives way to one of Madagascar’s most impressive geologic formations, called a tsingy. Ankarana is a place like no other, unless perhaps you count Sméagol’s lair, deep in the Misty Mountains of Middle Earth.
The razor-sharp limestone eroding under the northern Madagascar rains forms a veritable labyrinth of underground tunnels and waterways, brimming with every imaginable creepy-crawly the Nazgul might feel inclined to summon forth today—bats, most certainly, but also millipedes and centipedes as long as a kitchen knife, giant cockroaches that hiss, scorpions with their long curling, sometimes lethal tails, spiders and snakes and eels and crawfish and crocodiles, too. I stand, transfixed, in the Grotte des Cathédrales, perched precariously atop a mound of warm bat guano that dates back for decades, perhaps centuries. Eidolon dupreanum swirl restlessly in the airy heights above me, and beyond the dim limits of the glow cast by my headlamp, there are thousands and thousands of roaches. What would my mother think, I wonder, if she could see me now?
Ankarana is heaven-on-Earth for a bat biologist, and it is only natural that my Madagascar wanderings have led me here at last. Indeed, I intend to return to this site repeatedly throughout the year to sample both E. dupreanum and his smaller fruit bat cousin, Rousettus madagascariensis, for annual peaks and troughs in antibody response to pathogen load (a proxy for immune function), as well as for viral load shed in urine. Previous work suggests that bats might be more susceptible to infection during the reproductive season when their internal resources are otherwise preoccupied. I’m trying to see if this might be the case here, too—and assess whether cross-species transmission has anything to do with pathogen persistence.
It’s a wild, remote part of Madagascar, and we hike and bike for kilometers, stopping in small hamlets to chat with bat hunters. You find fruit bat—fanihy—on the hotely menus in this part of the world, and the residents tell me jovially that its taste is far preferable to all domestic meat available. In the midst of West Africa’s Ebola outbreak, likely the result of viral spillover from fruit bats to humans via the bushmeat trade, I can’t help but feel my work is timely.
Our park guide, Edmund, leads the way, efa zatra—already accustomed—to the beat-up bicycles, hot sun, and rugged terrain. Adapting my Malagasy quickly to his northern Sakalava dialect, I chat with him about bat biology. He asks me if the same Eidolon and Rousettus exist in North America, and I explain that Madagascar’s fruit bats belong to the family, Pteropodidae, which is restricted in range to Africa, Asia, and Australia. I attempt to elucidate the Gondwanan heritage that unites these continents—held together after the break-up of Pangaea—but it’s still fascinating, I conclude, that bats have not dispersed beyond this range.
“Satria afakaka manidina izreo?” he questions. Because they can fly?
Exactly, I say. And I marvel that this conversation is really taking place.
Edmund’s question strikes at the heart of biogeography, the science devoted to understanding why organisms inhabit the places they inhabit and how they got there to begin with. The theory of island biogeography holds that a given area will have an equilibrium number of species, balanced by perpetual forces of species immigration to that site and species extinction within that same site. In Madagascar, a land where over 90% of the plant and animal life is endemic, or found nowhere else in the world, this question is particularly pertinent. And it is complicated by the added concept of speciation, or the development of new species from old.
Much of Madagascar’s unique biodiversity can be explained by its longtime isolation—over 80 million years—as a singular body floating in the Indian Ocean. Some of its species, like the fruit bat, arrived to the island via dispersal from mainland Asia and Africa, then never really left and slowly drifted genetically into novel species types. Others were likely present on the Madagascan continent at the moment of its split from Africa and, later, India, and have speciated since via vicariance, or the geographic separation of a species’ range. For many years, it was believed that Madagascar’s extinct elephant birds—towering, flightless beasts over six feet tall—were the result of vicariance and subsequent radiation of ratites (the clade to which elephant birds belong) into the ostriches of Africa, emus of Australia, and moas of New Zealand. However, recent studies suggest that ratites may, in fact, have been flighted birds at one point and instead dispersed to various localities, then lost their flying abilities and diverged genetically. Like much of Madagascar’s fascinating flora and fauna, the true story remains a bit of a mystery.
But it’s no mystery that the Eighth Continent is a special place, and nowhere more clear than in the mysterious caverns and hanging valleys of Ankarana Special Reserve. No matter where I turn in Madagascar, I find myself encountering something amazing—indeed, just the other day, I ran across National Geographic Explorer, Luke Dollar, and was privileged enough to watch him measure a sedated fossa, yet another of the island’s endemic fauna—but somehow, Ankarana really hits home for me. I’m excited to continue chasing fantastic beasts in our creepy lake in the Misty Mountains for years to come…