DUELING DINOSAURS

V ISITORS TO THE MUSEUM OF

Natural History in ExpositionPark find it difficult not to be

overwhelmed by the sheer size and vi­brancy of the "dueling dinosaurs" thatnow grace the main toyer, thanks to agenerous gift from Museum Fellows Dr.S. Jerome and Mrs. Judith D. Tamkin andthe Tamkin Foundation. Towering aboveenthralled onlookers, Tyrannosaurus rex­the best known of all predacious dino­saurs-stoops to attack the rhino-likeTriceratops in the re-creation of a scenethat must have taken place frequently to­ward the end of the Cretaceous Period,some 65 million years ago. The installa­tion of this new permanent display, whichwill be completed by the end of 1996, isthe last chapter in a story that began somethree decades ago.

Following the removal of the fine artcollections to the Los Angeles CountyMuseum of Art in 1964, Dr. HerbertFriedmann, then director of the NaturalHistory Museum, decreed that the most

pressing priority of his reconstituted insti­tution was to create a new dinosaur halJ.Responding to Dr. Friedmann's challenge,Museum Trustee William T. Sesnon fundeda number of expeditions to Hell Creek inMontana for the purpose oflocating Creta­ceous dinosaur material complete enoughto place on exhibition. Ace prospectorHarley Garbani was retained to head thecollecting team, which he staffed mainlywith student volunteers.

Five consecutive collecting seasons inMontana benveen 1964 and 1969 yieldeda wealth of dinosaurian material, includingthree duckbill skeletons (Edmontosa~~rus),

two Tt'iceratops skulls--one associatedwith a partial skeleton, and the skull andfoot of a Tyrannosaul'us. One of theTriceratops skulls was complete, thoughpartially crushed, and has been on perma­nent exhibit since 1970.

"Vhen discovered, the Tyrannosaurusskull had been disarticulated into manypieces, and it wasn't completely reassem­bled until 1973. By tllen it had become

obvious that it was the largest and mostcomplete Tyrannosaurus skull known to

science, and it carried this distinction untiljust recently, when an even bigger T rexskull was found by a parry from the BlackHills Institute of SOUtll Dakota.

The Tyrannosaurus skull and footwere associated with additional limb bonefragments and vertebrae, some of whichbelonged to a second, smaller individual.The skull and foot were duly placed ondisplay bur with long·standing regret thatwe had nothing to fill the interveningspace l Then, in the mid 1980s, we ex­changed a cast of our skull for the cast ofa headless T rex skeleton that had beenfound by the Tyrrell Museum in Canada.In this way, both institutions acquired thematerial for a relatively complete (if par­tially fabricated) exhibit. The relocation ofthe Natural History Museum's Jurassicdinosaur skeletons from the main toyer tothe Governors' Gallery in 1992 finally re­leased a large enough space in which to

display Tyra,mosaul'us to good effect.

2 TERRA vO 33 NO.5. SEPTEMBER IOCTOBER 199&

LEFT

Tyrannosaurus rex bones being excavated from an

ancient stream channel near Hell Creek,

Montana, in 1969; a jaw fragment is visible at the

left. Photograph by Walter Frisbee.

BoTTOM, PAGES 2 AND 3

At the end of the 1969 field season, plaster

jackets containing dinosaur bones were loaded

onto pallets for transportation back to los

Angeles. Photograph by Walter Frisbee.

COlfER

The Tamkin Dueling Dinosaurs, Tyrannosaurus rex

and Triceratops, now on display in the main foyer

of the Exposition Park museum. Photograph by

Dick Meier and Dan Watson.

T ERR A VOL. 3] NO • SEPTEMBER / OCTOBER 1996 3

The idea of having the Tyrannosaurus:tIld Triceratops posed in interaction wasthe inspiration of Natural History Mu­seum Modelmaker Michael Stokes, whoprepared a model of his concept for con­sideration by Museum President and Di­rector James L. Powell. Dr. Powell in turnshowed the model to Dr. and Mrs.Tamkin: excited by the opportunity toprovide the museum with a distinctive hall­mark that would be particularly appreci­ated by our younger visitors, the Tamkinsoffered to underwrite its construction.

The armature or supporting frame­work for a skeletal mount can be eitherexternal or internal. A classic example ofexternal armature can be seen on themuseum's cast of the long-necked Chinesesauropod Mamenchisaurus(now on dis­play in the Governors' Gallery). Here theneck, legs, and torso are held together byexternal metal bands, and the whole skel­eton is supportcd upon three very visiblevertical steel rods.

The Natural History Museum helpedpioneer internal armature, where the skel-

eton is supported 011. a framework that liesinside the bones. This type of mount,which has been used on most of our otherdinosaur and fossil mammal skeletons,provides for a much more realist.ic poscbut has the disadvantage of necessitatingdrilling through and hence destroyingpart of the bone in the process. Evenwhen the mounting technique does notharm the skeletal components, paleon- .tologists are often unhappy at the pros­pect of putting real fossil bones inmounted skeletons because it is then diffi­cult to study them. However, a compro­mise was reached when assembling theDueling Dinosaurs.

We decided not to use the real Tyran­nosaurus and Triceratops skulls in themount-in part because we wanted themavailable for further scientific study anddidn't want t.hem drilled or otherwisedamaged, but mainly because they arevery heavy, each weighing almost a hun­dred kilograms (several hundred pounds).Clearly we did not want the skulls break­ing off from the relatively slender and

fragile necks in the event of a moderate tosevere carthquake temblor l

Although they were replaced by castsin t.he completed mounts, the real skullswill be located in nearby display caseswhen the installation is complete so thatvisitors may study them close up. Tocomplete the mounts, we incorporated asmany real bones and bone fragments aspossible: about 60 percent of the Tricer­atops is real bone, and about 15 percentof the TyrannosauntS. (The finishing ofthe casts is so realistic that it is difficult totell from a distance which element is realbone and which is cast.)

The Dueling Dinosaurs were as­sembled to our design by Research Cast­ing International of Toronto, under thedirection of Peter May, formerly of theRoyal Ontario Museum. May's skilledteam has mounted more than 300 fossilskeletons for museums throughout theworld. Although Research Casting's ex­perts are no strangers to Tricu'atops orTyrannosaurus skeleton mounts, this wastheir first interactive mount of the twospecies. As far as they can tell, this is theonly such mount in the world, and it iscertainly one of which they are extremelyproud-they rank it among their finest ef­forts to date.

The skeletons were mounted in mod­ules in Canada-the T rex divided intoseven units, the Triceratops into six-andthen shipped to Los Angeles for reassem­bly on site. The hip units of both animalswere so large that we had to remove thedoors at the museum's north ent.rance toget them into the building. We startedunloading the shipment at 8 a.m. onTuesday, April 2; in less than 24 hours,the two huge skeletons, each weighing680 kilograms (1,500 pounds) were upand in place.

The display was, however, far fromcomplete. Each skekton sits on a solidsteel base plate weighing 450 kilograms(1,000 pounds), and these needed to bewelded together after the fine tuning ofthe combatants' positions and covered bya platform so that the feet of the dino-

4 TERRA VOL )) NO 5 • SEPTEMBER I OCTOBER 1996

saul's will be resting on a flat surfacerather than being suspended above theground.

Finally, the inside walls of the foyerare being ringed with supporting exhibitsabout the people who made the conceptpossible, the different stages of theproject, and the context in which the di­nosaurs lived. Several displays will be de­voted to other kinds of Ii fe present onearth at the end of the Cretaceous Periodand on the narural history of the two ani­mals. \Vas T rex a predator or a scaven­ger> Was the Triceratops frill for display,defense, or temperature regulation?These and other intriguing questions willbe addressed.

As the school year begins, we lookforward to seeing visitors of all ages gaz­ing up at the dueling titans and learningmore about life on earth at the very endof the Age of Dinosaurs.

DR. JOHN M. HARRJS

Chief Curator, Paleontology

Of'POSll'e. TOP

During the 1969 excavations near Hell Creek,

Montana, a block of river channel sandstone

matrix containing Tyrannosaurus skull fragments

is encased in plaster to provide reinforcement for

the brittle bones while they are moved from the

field to the Natural History Museum. Photograph

by Walter Frisbee.

AlloY<

Museum Modelmaker Michael Stokes refines his

concept for the Dueling Dinosaurs. Photograph

by Dick Meier.

LEFT

William T. Sesnon (right), Mrs. Sesnon, and then

Curator Reid McDonald examine the plaster

jacket containing a Triceratops skull after it

arrived at the museum at the end of the 1965

Hell Creek field season. Photograph from the

Vertebrate Paleontology archive.

TERRA VOL 33 NO 5 • SEPTEMBER I OCTOBER 19~6 5