Biology Reference
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all. At local scales earthquakes, volcanoes, and windstorms annihilate chunks of habitat,
which are then colonized by species that live in the resulting light gaps. Those sun-lov-
ing newcomers are eventually replaced by shade-tolerant species, so that natural dis-
turbances further increase diversity by generating patchworks of succession in what at
first glance appears to be unbroken forest.
Tropical biotas are also among the most endangered anywhere, their most charis-
matic inhabitants often difficult to find. Ecotourists adore emerald-and-red quetzals and
iridescent blue morphos, and with coaching they might tolerate the jararaca pitvipers
whose venom chemistry inspired a popular blood pressure drug. Predators are usually
tough to see, though. Whereas in an hour a person might find dozens of snakes on a
Missouri hillside, I averaged one a day at La Selva, and after twelve months of fieldwork
I still hadn't seen all the species at that serpent-rich locale. Because rainforests don't
offer Serengeti-like vistas, we can't drive folks through them in a safari van, striped like
a baby tapir instead of a zebra, to show of the big cats. Instead, advocates need to cul-
tivate perspectives that make those places feel wild, even if one doesn't see much that
day. We should teach neophytes to flare their nostrils at unfamiliar odors, differentiate
splayed tracks of jaguars from parallel-sided prints of mountain lions, and distinguish
among the sounds of frogs and birds. With luck, visitors might overtake a white hawk,
as I once did, so close on an overhanging limb that the immaculate bird seemed at first
illusory.
My fascination with steamy venues began on a childhood sojourn in the Philippines,
enhanced by reading Raymond Ditmars's melodramatic tales of bushmasters and vam-
pire bats. 1 Years later, as a soldier I requested assignment to Panama, hoping to find
exotic creatures and avoid combat, but was stationed in Germany instead. So my first
tastes of the tropics came on grad school trips to Mexico and Guatemala. I've since
enjoyed a decade of visits to La Selva and sporadic stints elsewhere in Latin America,
Africa, and Asia. Studying feeding and defense in snakes justifies my travels, with di-
versity an overriding concern: How can so many species fit into hot wet places? Along
the way I've also been enchanted with other predators, as well as impressed by how loc-
al peoples' lives play out and dismayed by the loss of tropical habitats. Just as deserts
afford simplicity and clarity, I've learned, rainforests exemplify complexity and obscur-
ity.
Snakes are notoriously difficult to find in rainforest, whether rare, hard to see, or both.
In the 1960s Henry Fitch had heard that La Selva was unusually snaky, and after a
brief reconnaissance he planned several Costa Rican research transects. Former stu-
dent Donald Clark was set to serve as postdoctoral fellow, but Don got a job at the
last minute and his replacement, a mammalogist, mostly caught bats instead of snakes.
Henry ended up studying lizards elsewhere, but he told me about the field station, and,
encouraged by Rob Colwell, my Berkeley colleague who'd worked there for years, I
headed south in search of giant vipers.
About the size of Virginia or Austria and proudly committed to conservation, Costa
Rica encompasses an impressive array of habitats. 2 Soaring cordilleras accentuate the
country's long axis, separating Atlantic and Pacific coastal plains, and its capital is on a
central plateau. Getting to the Caribbean versant in 1981 was an adventure. I flew in a
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