Building Two Life-Size Pteranodon longiceps
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On May 14, 1999 the Canadian Museum of Nature (CMN) in Ottawa, Ontario unveiled two life-size flying reptile sculptures, giant male pterosaurs of the species Pteranodon longiceps. The goal of this display was to create a signature piece for the central atrium of the museum and to launch a fund raising effort for a new Fossil gallery. I had the privilege of creating the models for this exhibit. Previously I had created life-size reconstructions of two Ice Age mammals, the woolly mammoth, Mammuthus primigenius, and the giant beaver, Castoroides ohioensis, for the same institution. Those projects were undertaken was while I was on the museum's staff, working with other model makers. This would be my first major undertaking as a private contractor.
The museum had a fixed budget that was raised from the generous donations of staff, trustees, members and volunteers. As a result every attempt had to be made to save on costs. Thankfully due to the efforts of Mary Rose Saccu (Project Manager) and Cécile Julien (Development Officer), sponsors donated most of the moulding and casting materials. Early on in our discussions CMN paleontologist Dr. Steve Cumbaa asked me if it would be possible to create two distinct Pteranodons from one mould. By modifying the angle of the wings and the direction and details of the head in a second cast it was possible to have two different sculptures at a fraction of the cost of doing two original pieces.
Once we had decided to go with two P. longiceps I had the idea to depict them in an in flight conflict over a fish. I ran the idea by Dr. Cumbaa, Mary Rose, and Leo Saccu (Exhibit Designer); we were all in agreement. My original idea was to have the beaks of both Pteranodons clamped on the same fish, performing the same type of aerial acrobatics that Frigate birds pull off today. Leo's concern was that this composition would not make the best use of the 26-m (85 ft.) high Atrium of the Victoria Memorial Museum Building that houses CMN exhibits. We decided to show one Pteranodon carrying the fish, in an evasive dive followed from above by it's rival. I took this idea and developed the poses. I believe the end result is spectacular and shows the benefit of a collaborative effort. I may still create my original idea but for this space this was the best choice.
1/12th-scale models of the pterosaurs were first constructed under the guidance of Dr. Cumbaa. I always look forward to working with scientists such as Dr Cumbaa since they view the results with a critical eye based on scientific knowledge and an appreciation of art. The enthusiasm of scientists such as Steve also serves to regenerate one when the project reaches those dreaded tedious stages,.i.e. fiberglass lay-up. Valuable observations and critique were also offered to me by CMN paleontologists Dr. Mike Caldwell, Dr. Rob Holmes and Research Assistant Rick Day. The models were based on the scientists' observations, scientific papers and examination of specimens in the Museum's collections. The miniatures were modeled from the inside out. Scaled down versions of the skull, rib cage, pelvic girdle and major limb bones were created in balsa wood, wire, epoxy and then covered with clay muscle and skin. (Figures 1 & 2)
The next step in this five-month process was to scale the model up to the life-sized sculpture. To arrive at the full size model, a cast of the miniature was sliced at predetermined intervals. The cast was encased in a wooden box filled with expanding foam to prevent the sections from migrating. (Fig. 3 & Fig. 4)
Each of these slices created a mini template that was then projected to full size and cut out of plywood. The plywood templates were arranged perpendicular to a lengthwise cross section of the model. The gaps between the templates were filled with foam that was carved to the proper shape (Fig. 5). This form was then covered with modeling clay and detailed. The wings were a combination of wood, wire mesh, cardboard and body filler (Fig. 6).
Once Dr. Cumbaa approved this sculpture an eight-piece polyurethane rubber mould with fiberglass support jackets was made. (Fig.7 & 8) Once the mould was completed the original clay sculpture was discarded. It was from this mold that the finished sculptures were cast in fiberglass reinforced polyester resin (Fig. 9). The angles of the wings were changed in the mold for the second cast (Fig. 10). Once it was free from the mould the head was turned, the beak was closed and the wings were finished in an upswept position (Fig. 11). Metal armatures were incorporated into the casts to provide hanging supports. The sculptures have wingspans of approximately 7 m (24 ft), with the heaviest of the two weighing a little over 91kg (200lb) Each model is suspended in mid-flight by two 2mm (1/16 inch) diameter stainless steel aircraft cables.
For the exterior finish we chose a lightly textured hair-like finish similar to those seen in fossils of other pterosaurs such as Rhamphorhynchus, Sordes, Dorygnathus and Pteradactylus. Stiffening fibers called aktinofibrils are suggested in the brachiopatagium, the major portion of the wing membrane.
Acrylic paints and glass taxidermy eyes were used complete them. Since the colour of these beasts is unknown this was one area I was given some but not unlimited artistic license. We looked to today's ecological equivalents of pterosaurs - the soaring, open-ocean seabirds like albatross. It stood to reason that patterns that work today could also have worked during the Cretaceous. The scientists suggested using light colours for underneath, which would help camouflage it against the sky for fish looking up, and dark colours for the back to blend the Pteranodon into the greenish-blue Cretaceous chalk sea as a way to be less noticeable to its rivals. Taking these colour suggestions I was free to come up with the markings on my own using the 1/12th-scale miniature as a canvas. After a viewing by the scientists of my first attempt I took the model back and refined it based on their critique. My second attempt was accepted without change. For the head and crest: I drew my inspiration from brightly coloured male birds like the great blue heron (Fig. 12 & 13). For the back I chose a patterned body to acknowledge the reptilian nature of Pteranodon. Underneath I broke up the solid off white with some black edging and striping.
While I was preparing the two scale model Pteranodons, I had Jean-Guy Auger model their prey, the Cretaceous marine fish Enchodus, under the direction of Dr. Cumbaa. The 61cm (24 inch) fish was sculpted life-size in polyurethane foam covered with clay (Fig. 14). The fins were carved out of plexi-glass, and the teeth were individually modeled from actual 90 million year old fossils from Saskatchewan. Once approved this model was also moulded with polyurethane rubber. The finished plastic cast also benefits from lifelike glass taxidermy eyes. For color Dr. Cumbaa suggested a blue and silvery-white pattern similar to modern fast predatory fishes of temperate marine waters, such as barracuda, bonito or mackerel. The hapless prey is held in the beak of one Pteranodon with the other in hot pursuit, in hopes of stealing a free meal. Jean-Guy was also hired on to help me during the process of modeling, moulding, casting and finishing the life-size Pteranodon models.
All in all I am very satisfied with the final sculptures. The positive reaction of the client is always the prime objective in a project such as this, and the museum staff were enthusiastic in their comments. In the case of this project I also include as my clients those excited children that I saw at the unveiling that looked up at "my" Pteranodon sculptures with the same wide eyed wonder that I used to exhibit when I was their age and made my trips to the old Dinosaur hall. Maybe there is a future Paleo artist amongst them.
The Canadian Museum of Nature is located at 240 McLeod Street (at Metcalfe), Ottawa, Ontario, Canada.
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