8 August 2013
Everyone remembers the dinosaurs, but what happened after the dinosaurs went
extinct? They left a vacuum filled by giant and often forgotten animals:
the megafauna. The term megafauna, “big animals,” covers several groups
of giant creatures. However, naturalist Richard Owen honored only the
oldest members of the group with the special name, “dinosaur.” The
remaining giants, those that roamed the earth between 10,000 and 40,000 years
ago, are known by the (too general) term “megafauna.”
Today, Australia boasts a unique collection of animals. Not only do
these creatures look exceptional, they are also exceptional in terms scientific
classification. The duck billed platypus is classified as a
mammal, but has a much lower body temperature than other mammals and lays
eggs–earning it a special mention whenever biologists formulate a list of
standard mammalian characteristics. Indeed, the platypus is so
“different” that the first reports of its discovery were denounced as “a
fraud.”
Australia, also, has a large variety of marsupials, a
group of animals that carry their immature young in a pouch for a period of
time after birth. Not surprisingly, the prehistoric Australian megafauna
also include a wide variety of now-extinct marsupials.
Throughout millennia, arid periods threatened the survival of Australia’s
megafauna, but one particular arid period, their last, coincided with the
arrival of homo sapiens. There is intense debate about whether climate or
human interference caused the extinction. Perhaps, it was some of both.
However, extinction is not necessarily the same as “dying out.” The
megafauna are no more, but many of their direct descendants roam Australia
today–miniature versions of their ancient ancestors. The modern kangaroo
and wombat are direct descendants, “distant children,” of monstrously huge
versions of themselves. And huge they were. New and more precise
methods of calculating the size of the ancient mammals has revealed that they
may have been much larger than previously thought.
Prehistoric Australia’s strange collection of giant wildlife included Diprotodon, the Giant Wombat. Unlike
its relatively petite, modern descendant, this wombat weighed as much as two
tons. The remains of these giant creatures have been found all over
Australia.
The Giant Short-Faced Kangaroo,
Procoptodon, the largest known kangaroo that ever existed, stood about 7
feet tall and weighed 500 pounds. Its feet looked a bit like horse
hooves having only one large toe on each foot. Each of its front paws had
two long fingers with large claws. A full-size, lifelike replica is on
permanent display, along with other ancient Australian animals, at the Australian
Museum.
The Marsupial Lion, Thylacoleo, was
not quite as big as the modern lion, but had just as strong a bite. In
fact, this creature had the strongest bite for its size of any known mammal
species, living or dead. Its long muscular tail was similar to that of a
kangaroo, and it may even have been able to climb trees. The Marsupial
Lion is thought to have hunted large animals such as the giant wombat and giant
kangaroo.
The Demon Duck of Doom, Bullockornis,
is older than the typical megafauna species. Although living
closer to the age of dinosaurs, it was just too unusual to omit. This flightless
bird was about 8 feet tall and weighed about 500 pounds. Thought to
be carnivorous, Bullockornis had a huge beak, suitable for “shearing,”
which probably explains its threatening name.
The giant turtle, Meiolania, had
disturbingly devilish horns making its head almost 2 feet wide (measured from
the tip of each horn). The horns prevented the giant turtle from
withdrawing its head into its shell–but who was going to mess with it
anyway. Pulling its tail was not a good idea either. The tail was
ringed with armor-like skin and was tipped with spikes. At about 8 feet long, most animals probably
just got out of this turtle’s way as it crawled across the
prehistoric landscape.
One cannot research these giant creatures without stumbling across
the fact that all continents had megafauna–not just Australia. North
America had one of the most famous species and one of the last to go extinct,
the Wooly Mammoth. This enormous version of the modern elephant roamed the
northern extremes of North America about 12,000 years ago.
At one-ton (2,000 pounds), Andrewsarchus was the largest carnivorous land mammal
that ever lived. Bearing a resemblance to the hyena, on which it preyed,
it might be the biggest dog-like creature that ever
lived. It was certainly larger than the than biggest prehistoric dog, Canis Diris, the Dire Wolf. At
150 pounds, the Dire Wolf was a featherweight compared to Audrewsarchus, but
more than a heavyweight compared to its descendant, the modern wolf.
Remains of the Dire
Wolf have been found alongside those of the Saber Toothed Tiger in the La Brea Tar Pits of Los Angeles.
Perhaps the species that suffered the most indignity at human hands was a
giant version of the modern armadillo, Glyptodon. It lumbered through the forests of South
America and was about the size of a modern VW bug. Slow
and meaty, human hunters had both the patience and ingenuity to hunt and kill
this strange creature. Not only was its meat used for food, its shell was
used as a kind of prefabricated living shelter. In terms of size, its
shell provided something like the Torrid Zone equivalent of an igloo. As
human food and housing demands increased, the number of giant armadillos
decreased until the prehistoric housing bubble burst when this natural producer
of “prefabricated housing solutions” went extinct.
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