The Salt Lake herald. [volume] (Salt Lake City [Utah]) 1870-1909, 1897-04-25
New Theory Of Cave Blindness
Prominent Naturalists Now De-
clare That the Loss of Sight in
Blind Inhabitants of Caves Is Not
Due to Continual Darkness.


The interest which attaches TO blind
fishes and other sightless animal forms
which inhabit the blackness of caverns,
underground streams and deep sea lev
els, has received added zest. Several
leading naturalists now contend that
these eyeless animals and fishes have
not become blind through a process of
evolution resultant upon their becOm-
ing habituated to darkness. The new
theory is that the animal forms were
blind before they made their way into
the caves or underground streams. and
simply went into retreat because the
struggle for existence would naturally
be less harsh in such places, their more
favored brethren possessing optical ap-
paratus being little likely to go there.
Many leading naturalists still hold to
the opposite view, and the surprisingly
large number of blind forms which
make up the cave-fauna speaks strong
ly in favor of their theory, yet there
are other considerations which have
been emphasized by American natur-
alists. and notably by Mr. Garman
which leave this conclusion open to
doubt. OF first Importance in this con-
nection is the fact that a large pro-
portion of the animal types that are
actually blind, or partially blind, with
in their own cavernal domains have
blind representatives also living on the
free land surface; this is especially the
case with the myriapods, or thousand
legs, and beetles, but the condition re-
peatS itself more or less with nearly
all the other groups, some of which,
again, find their coecal representatives
in the abysmal fauna of the ocean. The
contention is therefore made, and with
some show of FEASIBILITY. that blind
ness in cave animals is largely acct
dental and represents merely herding
together of the blind animals of the
open land-surface into a retreat which
would be more congenial and protective
TO them in a struggle for existence
against more favored or more perfectly
constituted enemies. This view, which
is now in a measure advocated by Pro-
fessor Otto Hamann, author of a re-
Gently published and most elaborate
work on the cave fauna of Europe re-
ceives a certain amount of support
from the curious interassoeiation of
blind and well-seeing elements in the
cave faunas. 1t is open to the objec-
ton that scarcely any, if any, of the
absolute blind types are specifically
identified with seeing forms that live
much beyond the cave confines. Pro-
fessor Hamann seems to be convinced
that whatever may be the true eX-
PLANTATION of this blindness, it has. at
all events, not been Brought about as
the physiological expression of the eff
fects of darkness. He Furthermore con-
tends that caves. even those most lack
ing in luminosity, are not as dark as
they are commonly assumed to be- the
numerous riffs, clefrs and passages
permitting of the entry of an amount
of light 10 which the eye ought readily
to respond in its visual accommoda-
ton.
The attention of naturalists has for
many years been directed to study of
the characteristics of those animals
which habituallT pass their existence
in the dark inner recesses of caves. and
which have collectively been grouped
together under the name of cava fauna
The animals of this class comprise rep
resentatives of all the main branches of
the animal kingdom, with the excep-
ton of the echinodermata (sea urchins,
star fishes), and includes as well forms
that live in the fresh waters as those
that frequent the surface of the cav
erns or occupy the cracks and riffs that
traverse the bounding walls. a main