Book Hews and Reviews 
CONCEALING-COLORATION IN THE ANIMAL 
Kinepom. An Exposition of the Laws 
of Disguise through Color and Pattern: 
BeingaSummary of Abbott H. Thayer’s 
Discoveries. By GERALD H. THAYER. 
With an Introductory Essay by A. 
_H. Thayer. Illustrated by Abbott H. 
Thayer, Gerald H. Thayer, Richard S. 
Meryman, and others, and with photo- 
graphs. New York. The Macmillan 
Company. 1909. Price, $7. 4to xx-+ 
260 pages; 16 colored pages, 140 uncol- 
ored figures. 
The fundamental importance of Abbott 
H. Thayer’s law of obliterative or counter- 
shading, in animals, first made known by 
him in ‘The Auk’ for 1896 (pp. 124-120; 
318-320), is recognized by all students 
of the colors of animals. While it had been 
applied in two instances by Poulton, 
twenty years before, that eminent natural- 
ist writes, ““The far-reaching significance 
of the principle was unseen until A. H. 
Thayer’s great discovery in 1896.” “For 
ages,’ the same writer remarks, “the 
artist has known how to produce the ap- 
pearance of solid objects standing out on 
his canvas, by painting in the likeness of 
shadows. It has remained for this great 
artist-naturalist to realize the logical 
antithesis, and show how solid objects 
may be made to fade away and become 
ghost-like, or even invisible by painting 
out the shadows.” (Essays on Evolution, 
Oxford, 1908, p. 299.) 
In the handsome volume under con- 
sideration, Mr. Thayer’s son, Gerald H. 
Thayer, presents his father’s further 
elucidation of the law of counter-shading, 
and the results of his additional studies 
of concealing coloration. 
Mr. Thayer contends that the main, 
if not sole function of color is for purposes 
of concealment, in order that an animal 
may either elude its enemies or capture its 
prey. In ‘warning,’ ‘recognition,’ ‘signal- 
ing,’ or ‘banner’ colors, he has no belief. 
“This discovery,”’ he writes (introduction, 
by A. H. Thayer, p. 4), “that patterns and 
utmost contrasts of color (not to speak of 
appendages) on animals make wholly 
for their obliteration, is a fatal blow to 
the various theories that these patterns 
exist mainly as nuptial dress, warning 
colors, mimicry devices (7. ¢., mimicry 
of one species by another), etc., since 
these are all attempts to explain an en- 
tirely false conception that such patterns 
make their wearer conspicuous. So im- 
measureably great, in the case of most 
animals, must be the value of inconspicu- 
ousness, that such devices as achieve 
this to the utmost imaginable degree, 
upon almost every living creature, de- 
mand no further reason for being (although 
doubtless serving countless other minor 
purposes).”” 
Among birds, it is said, inconspicuous- 
ness or concealment is achieved; with 
but few exceptions, primarily by counter- 
shading, usually aided by markings, 
patterns or appendages which tend to 
further obliteration. 
The law of counter-shading, which 
explains how an animal is rendered incon- 
spicuous by being darkest above, where it 
receives the most light, and palest below 
where it is least lighted, is accepted as a 
demonstrated principle, and it now too 
well known to call for comment here. 
In the newly proposed law of oblitera- 
tive coloration, the invisibility of the 
counter-shaded bird is increased by the 
addition of a picture pattern, by which 
the bird is made to resemble the back- 
ground against which it is most commonly 
seen by its enemies or by its prey. Or, 
to quote the author, ‘The object’s ob- 
literatively-shaded surface must bear a 
picture of such background as would be seen 
through it if it were transparent” (p. 3). 
Thus, the American Woodcock bears 
on its plumage a picture-pattern of “dead 
leaves, twigs and grasses, variously dis- 
posed over shadow-holes, in a near view,” 
while the markings on Wilson’s Snipe 
represent “sticks, grasses, etc., with their 
shadows, at various distances.” The 
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