New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1903-12-27
COLOR CHANGE IN ANIMALS.
Theories Concerning the Whitening In
Winter

The winter whitening Of animals. though % n
interest biologists. is very imperfectfy
derstoOd. Most writer's satisfied TO believe cha.
this color change was perfected somehow under ths
action Of natural selection for the protective pr-
poses OF adaptation 70 environment It's origin theF
leave unsolved problem
find. however that the change has deep
physiological significance There is. for instances. IN
mammals definite sequence IN which ths various
parts OF the body whiten This sequence corresponds
70 the summer accumulation of fat in the pannicu-
lus adiposus. Thus the belly. where pezpheral fa-
is thickest. Is permanently white, and the rump.
where also fat accumulates thickly. is usually tina
first part to written in winter.
Many Northern mammals and birds not usually
regarded of the winter whitening category ara
lighter IN winter than in summer. The whitensss
white patches assumed in the former season CORE
spond TO the fat tracts. so that these species may
In the Northern summer most animals accumulats
fat, always in definite manner regards ths
Of deficient civilization and OF sluggish metaooisn
and the process of its accumulation Is, therefoIs
metahnIisr, s thSrefore Iovest Win ne onset q
winter cold the atrOphy may extend 20 the hairs
Their pigment Gas observed by Aetchnikonl IS tnSa
removed, always. however, commencing with th9ss
therefore greatest. should there be a change q
the same conditions In very cold countries they
perate regions the parts only where tat IS thicAess
Although augmented 1alT can llUS uhue- -
atrophy and loss OF pigment. | know OF no 80
where the color is replaced. Animals once WHIT
ened remain until the spring moulL
These facts apply broadly 10 birds ana u'alIia-ss
but the hare and sJOat are the species which nave
studied especially. .,,
Similar laws govern a great deal OF the distriou-
ton OF the white color Throughout tne NcfteoIeies
phyium, wherein the connection oeIWeeh WINS
color and the periphera fat tracts thus ndleauns
local atrophyl may be widely traced, Thus comes
tic animals, nearly all of which are prled most tOr
tendency to the development of white patches. u
both these and In wild animals the belly. Where o-
ours the principal fat tract Is the most ttsQulLy
white part; next follow the rump and parts OF tns
neck, OF the limbs and of the head -, -,
Marked exceptions are no doubt IreQlenuy 60
10 unusual arrangements OF the pannlcuiuS 80
posuS thus IN the badger a representatse go .. >
FAMILY IN which the back is usually Watler -
the belly. I ind COrresDOndingly eXCepuona A.
rangement OF the fat tracts.
The white OF the head-the "blaZe| OF horses. 20
not OF fat accumulation. but where the skin mn x
diately Overlies bone and membrane CrOntals aa4
nasalS and zySomatic arch). which thus seem "
DERIVING fat.
In many animals the hair atrophy assumes ne
FORM not or whitening. but OF badness MATT.ns
ment OF their peripheral fat layer: fattenng aus
lose their hair, while the badness OF man err
spends In position 70 the blaze' OF horses. ara -
pare ouItoeks OF monkeys 70 the white ruEaps :"
Yellow and red frequently follow the same rules
or distribution as white. They are well known ="
De fat pigments.
I must carefully guard myself against the sxtsn-
sion OF my theory to all where white Occes,s.
m VeTtebrates. 1t Is obvious that all MIN,
are subject to this atrophy, and that there nus.
highly probable from what have written that ~
known unsNenneSs OF animal cOloration - oel -
eNtSthai lilSlcdtion or uneven nutrition IN oine,
Nature.