ANIMAL BEHAVIOR—ERNEST P. WALKER 273 
One of the most remarkable modifications of feigning death of 
which I have heard was witnessed and described to me as follows by 
John N. Hamlet, of the United States Fish and Wildlife Service: 
Three of us recently saw a Cooper’s hawk (Accipiter cooperi) chase a spotted sand- 
piper (Actitis macularia). The piper dropped into the water and stayed under for 
several seconds. The Cooper’s lit on the stream edge a few yards down the 
stream. The sandpiper came to the surface and floated down the stream with 
its wings open flat on the water and its neck stretched out. It passed within 3 
feet of the hawk who gave it no more than a casual glance. The piper floated 
down stream about 20 yards and took off and disappeared. 
The live sandpiper drifted close by the hawk but was not recognized 
because it was not moving in its usual pose. This is a choice example 
of the effectiveness of ‘freezing’? and assuming an unusual pose. 
Mr. Hamlet has witnessed similar action by sandpipers on two other 
occasions. 
Bluff is another effective defense that is employed by many animals. 
Its best form is for the animal to face its enemy in a pose not usually 
assumed by it and that makes it appear as large as possible, ferocious, 
and threatening. Many, if not all, of the owls (Strigiformes) bluff 
by crouching low, spreading their wings at almost right angles to the 
body and ruffling the body feathers until the bird appears several 
times larger than it really is. The bittern does likewise, and most 
mammals bluff to some degree. A good example is the dwarf weasel 
(Mustela rixosa campestris), only about the size of a cigar, who stands 
his ground, opens his mouth wide, barks, and even attacks if need be, 
although its teeth and jaws are so small it can scarcely break the 
skin of one’s hand. The domestic cat’s (Felis cattus) high-arched 
back, bushed-out tail, and wide-open, snarling mouth present a good 
example, and many of us have witnessed the hestitation of a dog 
suddenly confronted by such an attitude. Often this hesitation 
gives the cat an opportunity to escape without having to fight. 
Fighting for mates is definitely beneficial to the species, for by 
nature’s law of the survival of the fittest, which must prevail through 
all species, only those survive that are best able to take care of them- 
selves. This, taken in its broadest sense, includes not only physical 
strength but mental alertness and adaptability to varying and new 
conditions. Males that are physical weaklings and would not father 
vigorous offspring are ordinarily vanquished in encounters for mates 
and therefore leave no progeny. By this process nature has consist- 
ently eliminated the unfit and has improved each of the species. 
The occasional maiming of individuals in their conflicts is not in 
itself injurious to the species, as such mutilations are not inherited 
and, if the parent was vigorous, the progeny stand excellent chances 
of being vigorous even though the parent may have been injured in 
some of its conflicts. 
