of a giant ground sloth from the ice age.
The giant ground sloth was one of the enormous creatures
that thrived during the ice ages. Looking a little bit like an
oversized hamster it probably fed on leaves found on the lower
branches of trees or bushes. The largest of these ground sloths
was Megatherium which grew to the size of a modern elephant
with a weight over five tons.
Giant Sloths had very large, dangerous-looking claws.
Despite their size they were probably only used to strip leaves
or bark from plants. Their teeth were small and blunt in keeping
with their herbivore diet. Examinations of their hip bones suggests
that they could stand on their hind legs to extend their grazing
as high as twenty feet.
Some Giant Sloths Really Carnivorous?
think that the large claws on Megatherium americanum
were used for stripping leaves and bark for its vegetarian
diet. Richard Farina, a paleontologist at the University
of the Republic in Montevideo, Uruguay, disagrees. He measured
the length of the olecranon process (the bony part of the
elbow where the triceps muscle attaches to the forearm)
on m. americanum and it was surprisingly short. The
shorter the length, the faster the arm can move. Faster
movement like this is usually the sign of a carnivore. Farina
thinks this 12 foot high version of the sloth might have
gone carnivore and hunted glyptodonts (giant armadillos)
that lived at that time. If so the sloth probably rolled
them over and stabbed them in the soft underbelly using
its long claws.
Like other giant creatures that disappeared at the
end of the Pleistocene period (about 10,000 years ago), Megatherium,
its smaller sloth cousin, Mylodon, and other varieties
of the giant sloth are now extinct. Only the small tree sloth
survives today. Or so scientists believe.
In the 1890's an Argentinean explorer, geographer
and adventurer, Ramon Lista, was hunting in a portion of
his country known as Patagonia when a large, unknown creature
covered with long hair, trotted past the party. To Lista the creature
looked like a gigantic armadillo. The party shot at the beast,
but the bullets seemed to have no effect.
Professor Florentino Ameghino, a paleontologist
in Argentina, heard the Lista story and began to wonder if the
strange beast was a giant sloth that had survived from the Pleistocene.
He might not have put much stock in the Lista story if it had
not been for legends he'd collected from Indians in the Patagonia
region about hunting such a large creature in ancient times. The
animal in the Indian stories was nocturnal, and slept during the
day in burrows it dug with it's claws. The Indians found it difficult
to get their arrows to penetrate the animal's skin.
large sloth standing on his hind legs could tower twenty
feet in the air.
Ameghino also had a piece of physical evidence.
A small section of apparently fresh hide found by a rancher named
Eberhardt on his property in a cave in 1895. The hide was studded
with small, hard, calcium nodules and would have been impervious
to the teeth of Pleistocene predators. It seemed likely that it
would have also resisted Indian arrows and Lista's bullets.
So sure was Ameghino this was the creature Lista
had seen he named the creature after Lista: Nemoylodon listai,
or "Lista's new Mylodon."
Expeditions to Eberhardt's and other caves, recovered
additional pieces of hide along with evidence the Eberhardt's
cave had been home to both men and Mylodon. With the development
of the Carbon-14 dating method in the twentieth century the age
of Mylodon remains in the Eberhardt's cave was settled.
Dung found in the cave was more than 10,000 years old. The skin
was estimated to be 5,000 years old. Conditions in the caves may
have preserved it making it look fresh to the eye and fooling
giant sloth appears on a stamp issued by Brazil.
No additional evidence has turned up that the giant
sloth survives today. What killed them? Like other giant species
of the Pleistocene period, climate change related to the end of
ice ages, may have been the culprit. A competing theory, however,
is that as man spread into regions occupied by the giant sloth,
he may have hunted them, along with the mammoth
and mastodons, to extinction.
1996-20006 Lee Krystek. All Rights Reserved.