From: Stephen <stephenbowden@home.com>
Reply-To: stephenbowden@home.com
To: dinosaur@usc.edu
Subject: Experts had thought only herbivores hunted in packs...
Date: Wed, 22 Nov 2000 22:56:22 -0500
An unfortunate picture caption from an article on the BBC website at:
http://news.bbc.co.uk/hi/english/sci/tech/newsid_1036000/1036004.stm
Dinosaurs "hunted in packs"
Palaeontologists have unearthed evidence in support of a controversial
theory - that large, meat-eating dinosaurs hunted in packs.
Experts had always thought that only plant-eating dinosaurs roamed in
herds.
The giant herbivores would have lived, walked and died together, based
on evidence gleaned from dinosaur graveyards and fossilised footprints.
But now palaeontologist Phil Currie has discovered two fossil bone-beds,
buried for millions of years, showing groups of massive carnivorous
dinosaurs.
In an interview for the BBC Television series Horizon, he said the new
finds are good evidence that huge meat-eating dinosaurs did hunt
together in packs.
'Social groups'
The first site, in Alberta, Canada, contained the bones of at least 12
large carnivorous tyrannosaurs, including young and old.
Remains of at least six giant meat-eaters were found at a second
bone-bed in Patagonia, South America.
Phil Currie told the BBC: "It seems to me that we have very convincing
evidence that large meat-eating dinosaurs formed these social groups
where the young and the old worked together, hunted together and lived
together."
But some experts remain sceptical. They say that the sites could have
been predator traps, where animals sank into sticky molten tar bubbling
up from deep within the Earth.
Or floodwaters spreading across the plains could have washed together
the remains of several unrelated dinosaurs.
Buried in the same place millions of years ago, the bones might look
like a pack when unearthed today.
Angela Milner of London's Natural History Museum said: "A collection of
bones in a bone-bed doesn't automatically mean we're looking at a
collection of animals that live together.
"Sometimes bone beds accumulate from large areas of the land where
floods have brought all kinds of animal remains together and mixed them
up."
Clash of giants
The two new discoveries also raise another intriguing possibility. In
most parts of the world, the largest meat-eaters and the largest
herbivores never walked the Earth at the same time.
The giant long-necked plant-eating dinosaurs died out in the northern
continents around 100 million years ago.
But plant-eaters like the massive Argentinosaurus lived on in the South.
And recent fossil finds suggest that fearsome predators like
Giganotosaurus, bigger than Tyrannosaurus Rex, were also around at the
same time in South America.
Bones of the two giants have been found only 80 kilometres apart.
Which means that in prehistoric South America, because of a quirk of
evolution, the largest meat-eaters could have fought the largest
herbivores in a Clash of the Titans.