Big Bakker article in June Discovery Mag

[MariusRomanus@aol.com]

"And now investigative research paleontologist Bob Bakker at the Wyoming 
International Dinosaur Society is pushing us into really uncharted dinosaur 
territory - behavior. By studying teeth of allosaurs, the top predators in 
North America about 150 Ma, Bakker has concluded that the animals we have long 
thought of as robotic eating machines (think land sharks) were nurturing, 
protective, and attentive to their young, which they probably raised to early 
adulthood." 

>From Discover Mag, June 2003: "Dinosaur Family Values". 

This looks like an article that is a rehash of Bakker's "Raptor Family Values" 
paper from Dinofest in 1997. As with articles like this, it gives a summary of 
Bakker's life's work, mentions his distaste for the "pompous, priestly 
language" of the academic establishment, etc... Good remarks come from the 
likes of John McIntosh... There are tid bits about his "lone wolf" reputation 
and such as well, coming from anonymous quotes of other paleontologists... such 
as from "A specialist in dinosaur anatomy"... Oh, it also says that "Raptor 
Pack", a summary of his research aimed at young readers, will be published this 
month. 

Bakker talks about ceratosaurs... and how they had low, long body plans with 
deep flexible tails... "A really good swimmer"... So, finding their teeth at 
surf sites made sense. The article says that these guys probably ate fish by 
the water's edge. Bakker says "Ceratosaur teeth are sharp, long, delicate, and 
rarely worn. Ceratosaurs were pretty careful in their chewing; they were making 
filets. Megalosaurs had thick, coarse teeth, good for crushing stuff. Allosaur 
teeth are sort of in the middle." This is part of the ceratosaurs liked 
different habitats than allosaurs deal. 

The article goes on to explain his findings from 33 sites at Como Bluff... How 
the teeth of adult and young allosaurs were basically the same, meaning they 
ate the same things (unlike crocodilians which show a different pattern)... 
Bones of prey exhibit baby and adult teeth marks... Baby teeth are found shed 
with adult teeth, meaning they were eating in the same place, feeding 
together... which leads to his "lairs", being not dens or nests, but just a 
communal feeding area. Meaty parts of prey (rumps, thigh, upper tail) were 
dragged to the lairs, and were buried by slow moving water (fined grained 
sediments), showing that they didn't just wash in. These lairs also contain no 
other predator teeth, saying to Bakker that the area was well patrolled by the 
allosaurs. Bakker explains that like modern hawks and eagles, allosaurs had 
extended families in which older siblings helped the parents to raise the next 
generation. 

Is that true? Do some raptors do that today? I never heard of such a thing. 

Something interesting is a remark about Como Bluff concerning camarasaurs. The 
article says that Bakker has found whole teeth, but rarely shed ones... meaning 
to him that this is the sign of migrations, being that the sauropods were not 
stopping to feed. Locales in the Cretaceous that have high percentages of shed 
teeth mean these were feeding grounds where the sauropods stuck around for an 
extended time. 

There's an interesting comment that Bakker makes about preservation that's 
counter intuitive to whatcha would think... A pristine and complete skeleton is 
pretty much a near-useless prize. "It tells you very little because it was 
never part of the food chain. The better looking the specimen, the less 
information it contains. You want chewed up junk." 

The article talks about Bakker's environmental scenario for the Como Bluff 
area; A plentiful wet season, and a lean dry season. So, what did the allosaurs 
do? A lack in juvenile allosaur teeth about 1/3rd of the way grown at these 
lair sites means that the allosaurs packed up and left during part of the year, 
only to return with better environmental conditions. The missing teeth were 
found at ancient perennial lake shores. So, during the dry season, everyone in 
the neighborhood corraled around water holes. He says, "We see evidence of 
broken bones, compression fractures, bite wounds, bacterial infections that eat 
away the jawbone. Our allosaurs just get wacked.".

The rest of the article goes on to express concern about Bakker's habit of not 
publishing in peer-reviewed journals, though he says that his reputation of 
spurring peer-reviewed journals is unfair. Kay Behrensmeyer from the 
Smithsonian, a fellow grad student from Harvard, and Phil Currie, are both 
quoted expressing concern. Bakker responds by saying that he does submit his 
work for review but that he prefers museum bulletins and symposia proceedings 
because "they publish longer papers and place more emphasis on long-term field 
work". The article says that Bakker's latest, most complete shed-tooth study, 
will appear in September as a peer-reviewed monograph by the University of 
Indiana Press. 

The article also says that some of his colleagues question the way he 
interprets his work. Jack Horner says "Dinosaurs shed their teeth on a regular 
basis. It was like a conveyor belt. Just because you find shed teeth doesn't 
mean they were feeding on something.". Brent Breithaupt, director of the 
Geologic Museum at the University of Wyoming says, " What I have one of the 
biggest problems with is the idea that 150 million years ago an activity 
occurred right there at a given spot. If we're talking about footprints, you 
can say, 'Yes, a dinosaur was there.' But I still believe that the teeth and 
bones were deposited somewhat randomly through a change in velocity of a stream 
or something like that." 

Bakker responds by saying that teeth are shed away from feeding sites, but only 
a few such cases have been found in his study. He says that the key point is 
that predators leave copious shed teeth where they feed heavily. He says that 
the patterns he is documenting have never been done by anyone else, anywhere.   
His interest lies not in the day to day life of a dinosaur, but in developing a 
time-averaged portrait of dinosaur behavior. The work has inspired researchers 
like Behrensmeyer to do similar studies on the environment of human ancestors 
in Africa by collecting croc teeth, and the finding of bones of adult and 
juvenile theropods mixed together in locales like Canada, Argentina, and Japan, 
are, as Phil Currie says, "in concentrations that are just too high to be 
coincidental." 

I know that the Canadian theropods are albertosaurs (or has it now been 
permanently changed to gorgosaurs?), but... Is Argentina Giganotosaurs?... and 
what is Japan?... Where can I get papers on these things??? 

Illustrations are by James Gurney. His feathered baby allosaurs are just 
adorable. <G>. And that's about it for the article, besides this: 

Bakker says, "Can I put my e-mail address in the story so graduate students can 
write me if they want to do this?"........  zorilla47@aol.com 

Kris