I grew up with an image like this in my head.
It is one of the giant ground sloths, the mylodon, a
9ft hamster-like creature which once roamed across Patagonia
in South America. Although almost certainly extinct
10,000 years ago, rumours persist that the mylodon still
lives in pockets of forest. These rumours were what
drove my great grandfather Hesketh Prichard to lead
an expedition to find it in 1900 and 1901. Thanks to
the Daily
Express,
I spent a month in Patagonia
looking for the giant sloth
and following his footsteps.
By
the early years of the last century, Prichard had established
himself as a first-class explorer, naturalist, cricketer,
journalist and, of course, big-game shot. He counted
men such as Robert Falcon Scott of the Antarctic, the
author Arthur Conan-Doyle and the African explorer Frederick
Courtenay Selous among his friends. Conan-Doyle based
part of his book The
Lost World
on Prichard's adventures in Patagonia.
We
are going to use the words of another of Conan-Doyle's
creations to track down the giant sloth's habitat -
its ecological niche - the "lost world" where
it still may live. Sherlock Holmes said: "When
you have eliminated all that is possible, whatever remains
no matter how improbable, must be the truth."
So,
what do we know about the giant ground sloths? Let's
go back to the very earliest mammals.
65
million years ago, those that were to survive the great
extinction of the dinosaurs probably came from the northern
hemisphere. From there, they colonised the world. The
first animals to reach what would oneday become South
America were the noto-ungulates and condylarths. Shortly
after their arrival, the sea broke through the Panama
isthmus and exiled them from the rest of Creation.
Without
big carnivores to harass them, they developed odder
and odder forms. There were the ground sloths - toxodon,
megatherium, gliptodon and our one, mylodon. There were
also tree sloths, anteaters and armadillos. There were
liptoterns, astrapotheriums and macrauchenia. "This
fellow is like a camel with a trunk," wrote the
author and giant sloth hunter Bruce Chatwin.
Just
3 million years ago, the land bridge at Panamá
resurfaced and - in what is called the Great American
Biotic Exchange - a host of efficient North American
predators such as puma and sabre-toothed tiger, rushed
south and wiped out many of the most entertaining species.
The giant sloths were among the exceptions.
The
sloths were tremendously successful in both South and
North America. They evolved into several species ranging
in size from cat to megatherium, which was as big as
an elephant. They established themselves from the Arctic
Circle almost to the Antarctic. They were hunted and
they may even have been farmed by early man. Most scientists
accept that the sloths' larger versions were victims
of the great extinction of big mammals which marked
the end of the Pleistocene. Some are not so sure.
The
first rumours that a giant ground sloth species may
still exist reached Europe in the 16th century. Sailors
brought home stories of "water tigers" backed
up by fossil bones.
This
creature is a "su" or "succurath".
Reported as early as 1558, it lived on the banks of
Patagonian rivers. It had the head of a lion with -
according to reports - "something human about it",
a short beard from ear to ear, and a tail armed with
sharp bristles which provided shelter for its young.
The Su was a hunter but not for meat alone. It killed
animals for their skins and warmed itself in the cold
climate.
In
1789, Dr Bartolome de Muñoz found Megatherium
bones near what is now Buenos Aires. He gave them to
the King of Spain, prompting the King to order a complete
specimen of the animal alive or dead.
Charles
Darwin, during his famous voyage of the Beagle, found
the bones of a mylodon among his "nine great quadrupeds"
on the beach at Punta Alta in northern Patagonia.
The
rumours gained more credence in the late 19th century.
The future governor of Santa Cruz province in southern
Patagonia, Ramón Lista, was riding in Santa Cruz
in the late 1880s when a shaggy red-haired beast resembling
what he called a "giant pangolin" trotted
across his path. He had time to loose off several rounds
from his rifle before it disappeared into the scrub,
and was amazed to note that they bounced off the animal's
hide. Lista only gave a verbal account of this story,
to an animal collector called Carlos Ameghino, who told
his brother Florentino Ameghino, who was one of Argentina's
most notable naturalists and later the vice-director
and secretary of the best natural history museum in
South America, La Plata, which opened in 1888 outside
Buenos Aires.
There
is now a giant fibreglass mylodon at Last Hope Sound
in Chilean Patagonia, where a German sheep farmer,
Herman Eberhard found a near-perfect mylodon skin in
1895. The skin was covered in bony nodules, which may
explain what deflected Lista's bullets. Eberhard believed
it was the skin of an unknown sea mammal. He hung it
on a tree where it remained until 1897.
Another
great Argentinean naturalist and explorer Perito Moreno
found it, boxed it up and sent it back to La Plata museum,
of which he was both founder and director.
Something
fishy was afoot, however. The skin's arrival coincided
with a story by Florentino Ameghino that a native Indian
had knocked down a mylodon with bolas - the balls on
string which they used with deadly accuracy - and that
he, Ameghino, had the skin.
Despite
being colleagues, Ameghino and Moreno were enemies.
They had strong personalities and different point of
views about natural history - and Ameghino was notoriously
arrogant. Their enmity started when they worked together
at the La Plata Museum, where Moreno was director. Perhaps,
the museum was too small for two celebrities like them.
It
is likely that Ameghino intended to pinch Moreno's mylodon
skin and say that it was the Indian's. In the end, he
didn't steal it and went quiet on his claims.
Moreno
brought the skin to the British Museum in London for
safekeeping. It is now held by London's Natural History
Museum. In a lecture to the Royal Society on 17th January
1899, he said the animal was long extinct. Dr Arthur
Smith Woodward, keeper of palaeontology, said, however,
that the skin was so fresh that, were it not for Dr
Moreno, he would have "no hesitation in pronouncing
the animal recently killed."
The
skin story caused a sensation. Giant sloth fever gripped
the British public.
Arthur
Pearson, who had launched the Daily Express newspaper
in 1897, at once despatched his star journalist, Hesketh
Prichard, to Patagonia to find it. The words of the
director of the Natural History Museum, Professor Ray
Lankester, went ringing in his ears: "It is quite
possible - I don't want to say more than that - that
… [the Mylodon] still exists in some of the mountainous
regions of Patagonia."
Head
for the Moreno Glacier and you are 150 miles north of
the Mylodon Cave and back in Argentina. My co-sloth
sleuth is Harvey Carruthers. There's another 800 miles
to go before you reach the northern end of Patagonia.
It's a big place.
The
Moreno Glacier is one of the biggest in the world, which
moves slowly in the vast Lake Argentino, the fourth
biggest lake in South America. This was the setting
for the climax of Prichard's year-long journey through
the region.
With
the backing of Perito Moreno, Prichard pushed further
than any western explorer into the Andes. He found and
followed a river he named Katarina after his mother,
Kate. My sister is called Kate. He found a new lake,
Lake Pearson. He also discovered a new subspecies of
puma, named Pearson's puma. All these stories, plus
accounts of his adventures and of the dying Tehuelche
Indian tribe he published in a book, Through the Heart of Patagonia.
Despite
local Indian legends of a mountain ghoul called iemisch
or yemische, which fitted descriptions of the mylodon,
he found no trace of any giant sloth. He wrote: "Although
the legends of the Indians were manifestly to a large
extent the result of imaginative exaggeration, yet I
hoped to find a substratum of fact below these fancies.
After thorough examination, however, I am obliged to
say that I found none. The Indians not only never enter
the Cordillera but avoid the very neighbourhood of the
mountains. The rumours of the Iemisch and the stories
concerning it, which, in print, had assumed a fairly
definite form, I found nebulous in the extreme when
investigated on the spot. Finally, after much investigation,
I came to the conclusion that the Indian legends in
all probability refer to some large species of otter."
All
of which brings us to the present day. Despite the fact
that Hesketh Prichard was vindicated by carbon-dating
- the Moreno sloth skin is about 10,383 years old, give
or take 400 years - there have been a number of sightings
of creatures which fit the mylodon's description, and
in locations ranging from the rainforest of the Amazon
basin to the southern Andean beech forests of Patagonia.
The
common features of mylodon's habitat are forest and
grassland; a forest big enough to support a breeding
population of these creatures; an area of land that
is sufficiently cut off from the world of humans that
people rarely see mylodons; and, most importantly, an
area walled in on all sides, be it by mountains, lakes,
glaciers, sheer cliffs like the plateau in Conan-Doyle's
book The
Lost World
or the walls of a volcanic crater. We're looking for
a pleistocenic refuge, which stops the animals escaping
and in which the animal survived the great extinction.
Hesketh Prichard would approve of this combination of
science and adventure.
The
forest theory is well supported. Since 1994, ornithologist
and Amazon biodiversity expert David Oren has left his
teaching post at the Emilio Goeldi Museum in Belem,
six times to look for the mylodon in the rainforests
of Brazil. He canoes up and down the Tápajos
and Jamauchím rivers uttering soul-wrenching
cries in order to provoke a response from mylodons.
Stories of mylodon sightings by local people are what
drive him.
In
1975, mine worker Mário Pereira de Souza claims
he came face to face with a giant sloth on the Jamauchím.
He heard a scream; he looked and saw the creature coming
towards him on its hind legs. The animal seemed unsteady
and emitted a terrible stench.
On
another occasion, Manuel Vitorino Pinheiro Dos Santos
was out hunting near the Tápajos when he heard
it, he says. Again, there was the scream. It came from
a tangle of vines 50 metres away. He dropped the game
he had shot and sprinted for the river. He heard two
more screams, which he says shook the forest, as the
animal moved away.
David
Oren has had some success. He has videotaped clawed
trees, taped minute-long screams he believes are the
sloth's call, and made casts of some big tracks which
had backwards-facing claws.
Now
we are going to work on the Mylodon habitat photo-fit.
Let's pretend that we have a map of areas in South America
fulfilling all the criteria we have gathered so far.
These are the forest "islands", cut off from
the rest of the continent and far away from people.
We can remove a lot of these areas by looking at what
Mylodon ate - or eats.
We
need to become forensic scatologists. Faeces discovered
in the Mylodon Cave in Chile reveal that it ate X and
X, so we can cut out areas which don't have those plants.
On
our new map, we can cut out more areas by working out
the minimum size that a healthy breeding population
of mylodon would need. For this, we must look at fossil
evidence, at similar browsing forest-dwellers and talk
to relevant experts to find out whether these beasts
moved around the forest in herds.
Now
we're getting somewhere. We need to know whether the
climate in the area where we know Mylodon to have been
fits the climate in the areas on our map. We also need
to check that there are sufficient levels of sloth-essential
minerals in the soil, such as cobalt and copper.
This
process of layering intelligence on to maps is used
by modern armies to predict their enemies' advances.
It is called "Intelligence Preparation of the Battlefield"
or IPB.
We
will be left with a handful of locations across the
continent. We can knock out a few more by interviewing
any zoologists who have worked in any of them and who
can make a case for there being no mylodons. Finally,
we need to take cameras to the best of the remaining
areas.
I
want to be able to stand in a South American forest
and say: "This is perfect sloth country: it's X
square miles, hemmed in on all sides; it has these trees,
these minerals in the soil, this climate, and it's relatively
untouched by man."
Our
methods of searching these areas can range from the
Oren technique of calling the mylodon through to infra-red
imaging.
This
will be the most thorough attempt to find mylodon yet
made.
This
project is not for the superstitious. Many of those
connected with the hunt for the giant sloth have died
before their time. Bruce Chatwin, whose seminal book
about exile In Patagonia was based on the giant sloth
story, died aged 48 in 1989. Ramon Lista was assassinated
in the Chaco´s forest in 1897 by two guides who
were leading him to the Pilcomayo River. Nobody knows
why.
Three
leading members of the Smithsonian Institute in the
19th century, who formed a science and drinking society
called the Megatherium Club, died in their thirties
and forties. The club's leader, William Stimpson, died
of tuberculosis aged 40. Robert Kennicott, died aged
30 of heart failure - possibly suicide - on a collecting
trip to Alaska. The ghost of Fielding B Meek, who died
young of TB, still haunts the Smithsonian. And Hesketh
Prichard perished of blood poisoning in 1922 aged 45.
These
tragedies are not discouraging the work of the Max Planck
Institute in Munich. Scientists there have identified
DNA from Megatherium faeces found in a cave in Nevada,
USA. The next generation of giant sloths could be roaming
the forests of southern Germany. But to a boy who was
brought up on stories of his great grandfather's exploits
in Patagonia, where's the fun in that?
(Additional
information courtesy of Juan M Diehl) |
