410 Evolution and Adaptation 
feigning instinct in higher animals, and attributes it to violent 
emotion, or fear, that produces a sort of swoon. He describes 
the gaucho boys’ method, in La Plata, of catching the silver- 
bill by throwing a stick or a stone at it, and then rushing 
toward the bird, “when it sits perfectly still, disabled by 
fear, and allows itself to be taken.” He also states that one 
of the foxes (Canis azar@) and one of the opossums (Didelphys 
azar) “are strangely subject to the death-simulating swoon.” 
Hudson remarks that it seems strange that animals so 
well prepared to defend themselves should possess this “‘safe- 
guard.” When caught or run down by dogs, the fox fights 
savagely at first, but after a time its efforts stop, it relaxes, 
and it drops to the ground. The animal appears dead, and 
Hudson states that the dogs are “constantly taken in by it.” 
He has seen the gauchos try the most barbarous tricks on a 
captive fox in this condition, and, despite the mutilations to 
which it was subjected, it did not wince. If, however, the 
observer draws a little away from the animal, “a slight open- 
ing of the eye may be detected, and finally, when left to 
himself, he does not recover and start up like an animal that 
has been stunned, but cautiously raises his head at first and 
only gets up when his foes are at a safe distance.” Hudson, 
coming once suddenly upon a young fox, saw it swoon at his 
approach, and although it was lashed with a whip it did not 
move. 
The common partridge of the pampas of La Plata (Hothura 
maculosa) shows this death-feigning instinct in a very marked 
degree. “When captured, after a few violent struggles to 
escape, it drops its head, gasps two or three times, and to all 
appearance dies.” But if it is released it is off in an instant. 
The animal is excessively timid, and if frightened, may actually 
die simply from terror. If. they are chased, and can find no 
thicket or burrow into which to escape, “they actually drop 
down dead on the plain. Probably when they feign death in 
their captor’s hand they are in reality very near to death.” 
