THE MANY MYTHS, SOME OLD, SOME NEW, OF ... - Gregory S. Paul

DINOSAUR MYTHS 75
Note that increasing the speed of very large animals simply by increasing the stride
length during fast walking is not the equivalent of maintaining a true running
performance.
SMALL DINOSAURS HAD SCALY SKIN UNLESS PROVEN OTHERWISE
Myth: Since scales are known to have been present on large dinosarus, and feathers
or fur are not known on smaller dinosaurs such as Compsognathus, it is usually
argued that the burden of proof is upon those who argue that dinosaurs were
insulated (as per Ostrom, 1978).
Reality: I believe this view exposes how an unsubstantiated prejudice in favor of a
traditional view can remain in force despite the lack of confirming or denying
evidence. The scaly integument of large dinosaurs does not establish that of smaller
species, just as elephants are a poor model for the integument of small ungulates. As
for smaller species, it is just as true that scales-which should be fossilized more
readily than softer insulation-have never been found on any examples, including
Compsognathus. The fossil record and objective thought do not, therefore, favor
scales over insulation in small dinosaurs. Insulation has evolved in mammals, birds,
pterosaurs, a number of insects, and even some plants, so its presence in dinosaurs
would not be extraordinary. It is widely agreed that at least some small dinosaurs
were endothermic, and hatchling hadrosaurs lived for months in nests exposed to the
elements. In both cases either feather or fur insulation would be important
thermoregulatory devices. Restorations of scaly small dinosaurs are just as speculative
as' those showing them adorned with feathers. Eventually fossil remains will
solve the problem (Figure 4).
TACHYMETABOLISMS BAD, BRADYMETABOLISMS GOOD
Myth: Because bradymetabolic animals are far more energy efficient than those with
mammalian-avian metabolic rates, it is widely thought that the former is inherently
the superior system to have, especially among big animals which are homeothermic
regardless of internal heat production. Only special circumstances, such as big
brains, flight, very cold habitats, or an inability to abandon an ancestral endothermic
system, justify the retention of high heat production. Since large dinosaurs fit none of
this criteria, they should have achieved homeothermy without tachymetabolism
(Feduccia, 1973; Baur and Friedl, 1980; Regal and Gans, 1980; Spotila, 1980;
McNab, 1983).
Reality: Pre ide (1985) explains that there has been a strong evolutionary trend that
favors higher energetics over energy efficiency, and thattachymetabolic endothermy
is the logical outgrowth of this trend. This is because higher energy systems process
and utilize information more rapidly than slower acting ones, an important advantage
in an energy rich universe (so powerful is this trend that it promises the evolution
of a super high energy information processing system via computers and robotics,
Barrow and Tipler, 1986; Moravec, 1988). This view is confirmed by the high degree
of success enjoyed by mammals, birds, leatherback sea turtles, tuna, and lamnid
sharks (all these appear to have metabolic rates elevated above the reptilian level),
and which range in size from 2 g to 200 tonnes, and live in places and climates ranging
from polar to tropical, from oceans to land. In comparison, big land reptiles have
been relatively rare, and have never exceeded much more than one tonne, thereby