ScAm

52 Scientific American, April 2020

BYRON ADAMS (

1 and

2 )

I

an Hogg and Byron adams peered out tHe windows of tHeir

helicopter as it glided over the rocky slopes of the Transantarctic

Mountains, dry peaks that rise above vast ice sheets just 600 kilo-

meters from the South Pole. Their eyes flitted across the ledges

and cliffs below. It was a sunny day in January 2018, and they

were searching for landmarks that matched those described in some

brief notes left by a deceased entomologist who, back in 1964, had

discovered an enigmatic creature in this desolate landscape. No one had seen it since.

The Transantarctic Mountains stretch more than

3,000 kilometers across the continent, from the shore-

line in the north toward the interior in the south, split-

ting the continent in two. The mountain chain, 100 to

200 kilometers wide, acts as a dam, holding back the

vast East Antarctic ice sheet, a dome that rises 3,000

meters above sea level. Glaciers fed by that ice sheet ooze

through gaps between the mountain peaks and slowly

empty into lower-lying West Antarctica. Dry winds

screaming off the eastern plateau keep the peaks them-

selves largely free of ice.

In winter, temperatures in the southern Transant-

arctics plunge below –40  degrees Celsius. Some of the

hard, thin soils on these peaks haven’t tasted apprecia-

ble amounts of water for tens to hundreds of thousands

of years, allowing them to accumulate caustic salts,

much like the surface of Mars. Yet despite the harsh

environment, a handful of tiny animals call these moun-

tains home. Hogg and Adams had been collecting sam-

ples since 2006, trying to learn which species live where.

The species that had been discovered in 1964, howev-

er—an insectlike animal called Tullbergia mediantarc­

tica —had so far eluded them.

The location they were scanning, Mount Speed, was

a low ridge in the southern Transantarctics, 700 kilome-

ters inland from the sea. Here Shackleton Glacier pours

from east to west through a gap in the mountains rough-

ly 10 kilometers wide. Hogg, a biologist at Polar Knowl-

edge Canada, spotted a cliff resembling one described

in the entomologist’s notes. The pilot landed above it,

and the passengers stepped out onto a barren rock slope

strewn with chunks of yellowish granite. They began to

methodically peek under one rock at a time. Within min-

utes they found their pale beasts—dozens of white, six-

legged animals smaller than sesame seeds.

The critters stepped slowly and purposefully among

the sand grains, navigating with antennae that were

soft and fleshy, like two outstretched fingers. The ani-

mals are extremely susceptible to dehydration, howev-

er, and within a minute of being exposed they began to

shrivel and die in the dry air. Over the next few days

Hogg and Adams found Tullbergia under rocks on four

different slopes along the lower end of Shackleton Gla-

cier. Sometimes the oasis they inhabited was smaller

than a basketball court.

Tullbergia is one species in a larger group of spring-

tails—primitive, wingless relatives of insects. Few peo-

ple have heard of springtails, although the soil in your

backyard probably harbors millions of them. These

minuscule animals are found around the world—and a

few species inhabit the sparse patches of ice-free ground

that dot Antarctica’s interior, where there is little to eat

but the occasional bacterium or microscopic fungus.

How Tullbergia and other springtails got to these

remote mountains, and how they survived dozens of ice

ages, is a mystery that scientists are eager to solve. Since

the 2018 expedition Hogg and Adams, a biologist at

Brigham Young University, have been performing genet-

ic studies on the rediscovered Tullbergia, as well as on

another species of springtail they found on the same

expedition. The studies, which they discussed with me

and which will be published later this year, will shed

new and surprising light on the history of these species,

which in turn may rewrite the story of how massive ice

Douglas Fox writes
about extreme polar
science, climate
and biology from
Cali for nia. He wrote
our 2018 article “The
Brain, Reimagined.”

1

IN BRIEF

Scientists have
found a tiny animal,
Tullbergia, living
under rocks
in Antarctica’s inland
mountain peaks,
where nothing
should survive.
Tullbergia seems
to have persisted in
the same place for
millions of years,
somehow avoiding
deadly ice sheets
and toxic salts.
Gene sequences
from Tullbergia and
other Antarctic
critters may explain
their survival and
might rewrite the
history of ice across
the continent.

© 2020 Scientific American