Evening star. [volume] (Washington, D.C.) 1854-1972, 1904-07-08
THE REFUGE OF SLEEP
REPTILES THAT BuRRoW IN MUD
TO AVOID INTENSE HEAT.
Animals Escape the Rigors Of Climate
in Summer as Others Do
in Winter.


From the New York SIM.
Winter sleepers among the animal kind
are all pretty well known. but owing to the
''aestivators." summer sleepers. being
for the most part inhabitants Of tropical
coutries. far removed from the path OF
trained observers, We are less acquainted
with the species practicing that means OF
stunning the heat and the drought of sum
mefr. Indeed. at present only one mammal
is known which does This is the tenric
OF Madagascar. a beast corresponding to
our hedgehog. and which retires to its bur
row and sleeps during the hottest three
months OF the year. However. 1t is believed
that the West African dormouse is sum-
mer sleeper: though this species when IT
has been brought to northern chimes. forgoes
it's aestivation and hlbernates like its rela-
tive. our familiar woodchuck
In not a few respects the suspended anil
nation OF aestivating creatures during the
intense heat of summer is even more re-
markable than that which obtains when
frost has dulled every function OF life.
Some microscopical animals. notably the
wheel animalcules' can be dried up into
a dustlike substance and yet revive as soon
as they get access to water, the germ on
which their vitality depends being evil
IDENTIFY protected in some manner not yet
fully understood.
Aestivation.
In South America and Africa various rep
tiles aestivate. If not in the manner de-
scribed. at least perfectly that their
summer somnolence is quite comparable
with the winter sleep of the temperate zone
forms thereof In the llanos. or plains OF
Venezuela, the alligator, the land and fresh
water tortoises. the boa constructor and
several of the smaller kinds of serpents lie
motionless in the indurated mud during the
bot lAI 49,
their dormancy is by no means so perfect
as that of some hibernators. a marmot. or
a hedgehog. or a woodchuck. for instance:
either one of which. when In the depth OF
Its winter torpidity may be tumbled around
like ball, and yet. except for a few feeble
respirations. exhibit scarcely any sign that
1t is conscious of being despitefully used.
In Brazil. Australia and South Africa liz
ards, frogs, tortoiSeS and insects pass
months of the rainless season incIosed I'm
hard earth. and in India many species OF
fishes during the dry season and long-con-
tinued droughts live in torpid condition.
imbedded in the indurated clay DR.. Day
has. indeed. put on record Instances in
which fishes have survived in this condi-
ton for more than one season. Ponds
known to have been dry for several months
have Swarmed with scaly inhabitants as
soon as the accumulation of water relea sed
them from their hardened bed
In our own Arizona, a land of great sum-
mer heat and drought. much the same phe-
desert, surrounded on every side by an arid
region. across which It would have been
scarcely possible for water fowl to convey
the living spawn of fishes batrachians,
as soon as the thunder showers fill them are
found to contain fishes. frogs and fresh
water mollusks of which not a trace could
previously be seen.
African Mudfsh
But perhaps the best and most extraordI-
well as the best known Of such in
| stances of aestivation. are those OF the
mudfish OF Africa. and its relations In the
rivers OF South Africa and Queensland
which are provided not only with gilIs but
with rudimentary lung. They can thus
breathe ordinary air, and at the time they
are incased in mud they leave a small OPEN
ing through which they can inhale It,
Some land molluSks are singularly sensi-
tive to heat and moisture. The desert snail
lies hidden during the day. but when the
sun goes down and the heavy night dew
covers the heritage II creeps forth to feed
retiring before the heavens are ablaze with
light The same species has been known to
remain glued down to a board In a museum
case. and after a lapse of four years. to
the amaZement OF the curators revive after
being plunged into water.
Hfbernatfon and aeStivation are prac-
tically the same. We have the paradox of
the same animal being able to embrace
both methods of escaping the fnconyeni-
enceS of climate.
As provision for enabling animals which
cannot migrate to survive within the area
they are thus forced to continue to inhabit
both modes of avoiding the extremes of tho
weather are peculiarly useful and as we
find land shells and the bones of reptiles I'm
the trunks Of fossil trees we are justified
In concluding the Information and aestiva-
ton prevailed in the most remote times,
the animals having crept into the places
where their stony remains are now found
to escape the rigors OF the carboniferous
climate.