The model was then cut into smaller sections. and care was taken to seal up all holes. The volume of the model was measured by dropping the sections into a graduated rylinder and reading off the displacement of water. (Walking dinosaur costume) This is accurate to within about 3 percent. From this, the estimated volume of the actual dinosaur is calculated. Weight is a simple function of the volume and the density, or specific gravity. For example, the specific gravity of water is 1.0 (1 kilogram of water equals I liter). Animals are mostly water. Bones are denser, but most animals float because of their air-filled lungs. So the specific gravity of paleodinosaurs and early theropods wils about 0.9. However, the extensive air sacs of birds make them less dense, at about 0.8. The avetheropods probably had better developed air sacs than early theropods, but less than birds, so they are given intermediate specific gravities of 0.85. Since I believe small dinosaurs were feathered, and since both flyrng and land birds’ feathers usually make up about 6 percent of their total mass, this value is added to those animals below 100 kg. The bigger ornithomimids may have been feathered, but probably only partly so, (Realistic dinosaur costume)like ostriches, so their possible feathers are ignored. Multiply the volume by the specific gravity and you have the weight of the dinosaur.
Weights based on multiview skeletal restorations have a plus or minus eruor value of about 15 percent. (Animatronic dinosaur)This is quite acceptable since individuals can vary this much in their weight as their conditions change. Indeed, I model the dinosaurs in “lean” condition, without the seasonal deposits of fat that could have regularly boosted their weight by 15 percent or more. For those skeletons drawn in side view only, care was taken to follow what is known about the widths of their body parts, and the accuracy of their weight estimates is only a little less. Species for which a good skeleton is not available are estimated from species of similar form. Of course, such weights are more approximate.
Note that the weights are those of specific specimens, not averages for the species as a whole. (Life like animatronic dinosaur)I try to give weights for more than one specimen to give an idea of its range. The great bulk of a species’ population will be near the population’s average weight, and since such typical-sized skeletons are what we can expect to find in the fossil record, many of the weights given here are close to average, or under it if only one or a few juveniles are known. A small but zubstantial portion of a population will exceed the average by 30 to 50 percent, so it takes very large ntunbers of remains, such as those known for Coelophysls bauri or Allosourus atrox, to have much chance of catching these. Exceptional “world record” specimens often bulk twice the population’s average weight, but they are so rare that their chances of being recorded in fossil dinosaur populations is virtually nil.