Evening star., 1937-09-23

Seventy or eighty million years age
Nature started a momentous experiment.
She evolved group of warm-b -blooded
animals which gave birth to living young
at a considerably developed stage,
nursed and cared for them during the
helplessness of infancy and after q
fashion educated them.
These animals were primarily insect
eaters-at least their teeth were best
fitted for this sort of diet. They were
"insectivores," an order represented to-
day by such lowly, secretive creatures as
the shreWs. moles and voles. These have
stuck closest to the ancestral ways. They
are like the branch of an ancient family
which has remained for countless genera
tions on the old home farm while the
collateral lines have been wandering over
the earth and establishing homes for
themselves in all countries. They retain
best the family tradition.
The scattered bones of this ancient
order of animals are stressed by DR..
George Gaylord Simpson of the Amer
lean Museum of Natural History in his
monumental report on the mammals of
the Crazy Mountains area. in Montana,
Just issued by the Smithsonian Institu-
ton. These creatures lived about TO-
100000 years ago, just prior to the time
when the ancestors of most e2tant warm
blooded creatures made their appearance
on earth.
Other lines of mammals-the fruit eat
ers, the flesh eaters and the grass eaters
-branched off from the insectivores and
specialized in their own ways. They
populated every conceivable niche of
nature open to them and developed ways
of life suitable to survival in these
inches. The insect eaters stayed put, re-
tanning the old customs but improving
on them to meet changing conditions
They had started the line which was to
lead eventually to the great apes and
man.
The insectivores of the paleocene, Dr.
Simpson believes, either are ancestral
directly to the modern creatures of the
same order, or belong to closely related
lines. This family has changed little in
100000 years, relative to the very great
changes in other mammalian orders.
They are, says DR.. Simpson, 1.-The most
primitive of all living placentaEmam-
mails"
The insectivores make their first ap-
pearance in the Cretaceous geological
period preceding the time of the Crazy
Mountain area formations. From them,
DR.. Simpson believes, arose all the orders
of mammals in which the young are
carried inside the bodies of the mothers
until they are completely developed. Thus
they are distinct from the marsupials
whose young are born in very imma-
ture condition and develop in the
pouches of the mothers, and the mono
tremes who lay and hatch eggs like birds
or reptiles.
Man himself, according to this con-
ception, may be considered as remotely
derived from the earliest insectivores.
Through millions of generation the va
rious stocks diverged more and more
from the insectivore ancestry. But the
Crazy Mountain creatures are still rela-
,tively close to the beginning. All the
placentals among them have suggestive
insectivore characters In fact, Dr.
Simpson says, If no intermediate steps
were known between then and the pres
ent all might be classified in this general
stock.
Among these Crazy Mountain animals
are found representatives of one offshoot
from the primitive insectivore stock
destined to lead eventually to the cats,
dogs, bears, seals, minks, offers, etc.-in
other words to the great order of carni-
vores or meat eaters. This group of
mammals were becoming adapted, like
some of the great reptiles which still lin
gered, to prey Upon their fellow creatures,
One Of these primitive carnivores rep.
resented IN the collection is the clseno-