Charlie Jacoby

freelance writer broadcaster editor

Giant sloth

Charlie Jacoby went as principal expert to South America for Giants of Patagonia, filmed in 2005, which aired first on the History Channel in the USA in April 2006 and is due out in the UK in 2007.

Part of the History Channel series Digging for the Truth, presented by Josh Bernstein and directed by Priya Ramasubban, the programme Giants of Patagonia showed viewers that the giant sloth may still exist. 

Click here to go to the Digging for the Truth website

Click here to buy the Giants of Patagonia film

Below is Charlie's script for a TV documentary proposal about the giant sloth, that you can also watch here:


Charlie and sloth

Prichard at home

Arthur Conan-Doyle

Scott of the Antarctic

FC Selous

Prichard on a horse


Perito Moreno

Ramón Lista

Giant sloth at Last Hope Sound

Megatherium Club members

A mylo-bin in Puerto Natales


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)



Charlie Jacoby
c/o Frontline
13 Norfolk Place
London W2 1QJ, UK
Tel: 07850 195353
From abroad, tel: +44 78 50 19 53 53
Skype: charliejacoby


Click on these for more

[Clip from Giants of Patagonia, part of Josh Bernstein's Digging for the Truth series on the History Channel - 3.6Mb wmv file] 

Click here to visit the Digging for the Truth website] 

1.4Mb jpeg of the Daily Express giant sloth story]

[1.2Mb jpeg of the Daily Express giant sloth preview]

[TV documentary proposal -
5.9Mb wmv file]

[Hesketh Prichard's book Through the Heart of Patagonia, translated into Spanish and republished in Buenos Aires, with a foreword by Charlie Jacoby. Click here to buy it]

Click here to buy the History Channel DVD/video Giants of Patagonia website, featuring Charlie Jacoby]