Akawaio team member
Franklin George rests
after a day of hacking
through the jungle
and hauling supplies,
often under a steady
rain. During the trek to
Weiassipu, the team set
up shelter each evening
and wrung out their
clothes. “The jungle
just swallows you down
day after day,” says
writer Mark Synnott.
“We were constantly
soaked and slathered
in mud. We called it
living in mud world.”rocks”—sometimes called “houses of the gods.”
Unlike typical mountain ranges that often
form in linked chains, tepuis tend to stand
alone, emerging from the rainforest like islands
poking out of a foggy ocean. A few of their
summits can be reached by hiking routes, but
most are ringed with sheer cliffs—some up to
3,000 feet tall—and often are festooned with
spectacular waterfalls.
Geologists tell us that tepuis are the remnants
of an ancient plateau, called the Guiana Shield,
that once formed the heart of the supercontinent
known as Gondwana. Hundreds of millions of
years ago, when this part of South America was
connected to Africa, the Guiana Shield stretched
across parts of what is modern-day Guyana,longer than in equatorial rainforests like this one.
For millions of years, the frogs here have followed
an array of evolutionary pathways, resulting in
a profusion of species in all shapes, sizes, and
colors, and with astonishing adaptations.
More than a thousand amphibian species have
been described in the Amazon Basin alone—
from jewel-like poison dart frogs (named for
their primary use among Indigenous people),
to glass frogs (with skin so thin it reveals their
beating hearts), to milk frogs (which live high
in the canopy inside water-filled tree holes), to
the recently discovered zombie frogs (that spend
most of their lives underground). Many of these
have yielded breakthroughs in medicine, includ-
ing new types of antibiotics and painkillers and
potential cancer and Alzheimer’s treatments.
Scientists believe they’ve identified only a
fraction of the world’s frog species. Meanwhile,
the ones we do know of are disappearing at an
alarming rate. By some estimates, up to 200 frog
species may have gone extinct since the 1970s,
and Bruce and other biologists fear that many
others will die out before we even know they
exist. What secrets about evolution, medicine,
or other mysteries would be lost with them?
Bruce refused to dwell on such gloomy rumi-
nations. He focused instead on the wealth of
biological treasures these rainforests still held.
“The potential for future discoveries in the
Paikwa is virtually limitless,” he told me, his
voice filled with his trademark enthusiasm. But
he also knew that time was running out—not
just for the frogs but for him too.
G
UYANA IS SOMETHING of
an oddity as the only English-
speaking nation in South America,
a legacy of its history as Britain’s
only long-term colony on the conti-
nent. Most of the country is covered
in untracked rainforest, but in the
far northwestern corner, the Pakaraima Moun-
tains run along Guyana’s border with Brazil and
Venezuela. Here, several table-topped moun-
tains, which resemble the monumental mesas
in the deserts of the American Southwest, rise
sharply above the dark green canopy of the
Paikwa River Basin. To the local Pemon peo-
ple who’ve lived in their shadows for centuries,
these otherworldly peaks are known as tepuis
(pronounced tuh-POOH-eez)—or “sprouting
48 NATIONAL GEOGRAPHIC