Evening star., 1933-05-15
BIG BRAIN FOUND
IN RARE GORILLA
c. U. Study May Show High
est Intelligence of An
imaI Kingdom.

What Is believed to be the first scien-
tdc study of the brain of q creature
which. next to mansRlone, may repre-
sent the highest mental development
in the animal kingdom. has just been
reported by DR.. C. j. Connolly OF Cath
olic University.
The brain studied was that Of Okero.
the 3-year-old mountain gorilla at the
Zoo who died a few months ago. 1t
was turned over by the Smithsonian
Institution to DR.. Connolly, who has
made specially of comparative cere-
bral anatomy.
Gorilla brains on which measure
ments have hitherto been reported
have belonged to the sub-species of
coast gOrillaS. Mountain gorillaS, which
live in more rigorous environment
in the Belgian Congo, have very rarely
been in captivity. and superficially their
behavior indicates a somewhat higher
intelligence.
Appear Startling.
Specifically considered. DR.. Con-
nolly's findings were somewhat start
ling The brain of this baby gorilla
he weighed only 40 pounds in good
health while the adult male Of the
species may go as high as 400 pounds
was absolutely one of the largest ever
found in great ape. 1t weighed 1865
grams. little over pound. The
average weight of the brains Of six
adult female coast gorillas reported by
DR. Connolly was 1913, about three
quarters Of pound. The average
weight of three young male coast 60
rillas, comparable in age to this one,
was only 1888 grams.
Assuming the gorilla's brain growth
rate to be about the same as that Of
a human being. it might be calculated
that by late adolescence this one would
have grown at least one-third larger
and reached weight or more than
600 grams The lightest normal human
brain weighs around 1.100 grams, and
has been considered more than twice
as heavy as the heaviest ape brain.
Thus there might be the implication
that the mountain gorilla represents a
considerable upward step from the level
Of the great apes toward the place OF
homo Sapiens.
Must Be Modified.
But such a conclusion must be
greatly modified by critical considera-
tions. DR.. Connolly points out, 1t has
been found that the anthropoid brain at
birth already has attained about 10
per cent of it's mature growth, while
tlle DTdul WeleIlJ OF HuIIldI lllldIlt Is
only SO per cent of that of the adult.
The gorilla baby's brain may have been
about as big as it ever would have been.
1t is not even certain that he would
have had bigger brain than the adult
male coast gorilla. All the adults of
this species examined were females. 1t
has been ascertained that the female
gorilla's brain is only about IS per cent
as large as that of the male. Besides
there are some technical weighing prob
lens to be considered. Weights vary
slightly. depending on whether the
fresh or preserved brain is weighed.
The outstanding difference Is between
the weight of this brain and those of
coast gorillas of comparable age.
Actual brain weight itself has little
meaning, it is explained, but the ratio
of brain weight to total body weight is
sometimes taken as very rough index
of intelligence. The mountain gorilla
probably is heavier than the coast
gorilla and would require a relatively
heavier brain.
Cerebellum is Larger.
The baby gorilla's brain was typically
anthropoid. 1t had a relatively large
cerebellum as compared to the cere-
brum. as is characteristic of the ape
brains. The cerebellum is concerned
with the functions of balancing and