The Dinosaurs of Wyoming - Wyoming State Geological Survey ...

CHAPTER XII
The "Sacral Brain" of Dinosaurs
The unusual enlargement of the spinal canal in the dinosaurs
has long been known and commented upon by various
authors, and many attempts have been made to explain the
presence, in the sacral region, of a mass of nerve material
often many times larger than the brain. It must be remembered,
however, that there was a large space around this
"sacral brain" and a cast of the cavity in the sacrum is probably
twice the size of the actual enlargement in the spinal
corel.
The best discussion of this "sacral brain" is that given by
Professor R. S. Lull, Professor of Vertebrate Paleontology at
Yale University, and I am quoting extensively from his article,
"On the Functions of the 'Sacral Brain' in Dinosaurs."
The complete reference will be found in the bibliography.
"Branca, in a discussion of the fauna of 1'endaguru, East
Africa, makes a number of thought-inspiring comments upon
the huge sauropod dinosaurs which the formation contains.
Among other points he is striving to account for the maintenance
of their immense bulk upon a possibly meagre diet by assuming
digestive powers of extraordinary efficiency. For this
he offers the following explanation:
"One may be inclined to look for the ability to take care of
food solely in the stomach, intestines, or liver. However, in the
dinosaurs we may take into consideration something else, i. e.,
the 'sacral brain,' if we look upon the swelling of the spinal
column in the sacrum as a 'brain.' According to W.aldeyer, it is
indeed thinkable that the sacral brain in dinosaurs had a certain
independence, and cared for the functions of nourishment,
digestion, and procreation [bold type mine], also that through a
particularly strong innervation it had become especially powerful,
more powerful than the strongest digestive organs could be
without such a sacral brain. In man there appear still to be
traces of this, but here the sacral section of the spinal column
is completely surpassed by the braili.
Dinosaurian Feeding Habits
"Our assumption of feeding habits based upon the character
of dinosaurian dentition justifies the following conclusions:
"Theropoda-These are the carnivorous dinosaurs in a
strict sense, with teeth which were in the main prehensile and
as such confined to the forward portion of the jaws. They
must have been used for rending the prey, for in many instances
they are sharp-pointed and compressed, with finely serrated
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