Editor Popular Science Monthly:
IN your February issue Mr. S. F. Goodrich brings up the question whether animals ever "play 'possum." He suggests that the apparent helplessness of certain animals when attacked is real; that what is popularly ascribed to cunning is in reality due to fright — a faint and not a feint.
This theory is new to the great majority of those who have observed the habit referred to; but its newness is not of itself a serious objection to it. Many familiar phenomena have waited long before receiving correct explanation. It has always been taken for granted that animals passive in the presence of danger were attempting deception. Rarely has any other explanation of their conduct been offered; but it does seem almost incredible that our far-away kinfolk should be using that distinctively human device — simulation.
Many of these acts can be satisfactorily explained on either assumption. The opossum may at times be unable to move because of his fright, or he may assume the passiveness of death as his surest hope for life. Which appears the more reasonable? Granted that it is difficult for us to credit the animals in question with sufficient intelligence and self-control to select deliberately such mode of defense, docs not the other theory involve us in much greater difficulties?
Do the lower animals ever feign any condition? If this question can be answered positively, it seems to me that we shall have the solution to the other problem. The cat, when playing with a captured mouse, appears to feign unconcern and forgetfulness while looking away from its victim, and surprise on seeing it again. Probably there are very few persons who have not at least once been deceived by the disabled appearance of birds when their nests or young were approached. Very many of our birds under these circumstances act so as to draw attention to themselves, and when pursued keep just out of reach, luring the pursuer to his greatest efforts by seeming to have reached the maximum of their speed. Finally, the foolish one, with feelings injured, gives up the chase in disgust. Are the birds conscious that their appearance is deceptive? Fear certainly did not make them really helpless. If it be admitted that there is hypocrisy in such cases, then it may not seem impossible for even these stupid animals to feign other conditions, not excepting that of death.
If the opossum while in this passive state be thrown into water, its passiveness will be modified somewhat, but will still be maintained. Its nose will be kept above the surface, and it will paddle away so very gently that the motion is hard to detect. If while "dead" a stick be put into its open mouth, it will quietly close on it with its teeth, and may then be carried long distances swinging from the stick, but showing no other signs of consciousness; or it may be carried by the tail, it doing the holding. Do these facts, which none acquainted with the habits of opossums will question, sustain the theory of paralyzing fear?
The fox also appears helpless sometimes when caught, and there are instances recorded of men being severely bitten because of too much faith in its apparent innocence. The toad w hen captured frequently makes a complete surrender, closing its eyes and settling down to apparent listlessness. If everything remains quiet, its eyes will soon open very gradually, closing again if danger be still visible; if not, it will prepare to move. If the enemy be discovered while it is trying to escape, it again assumes its former submissiveness.
The actions of the spreading adder are also curious. If approached, it makes a hissing noise and starts forward, looking as hideous as possible, as though it would frighten its enemy. These motions it will repeat several times if touched with the finger or a stick; but finally it seems to despair of relief by that method, and throws itself on its back and utterly refuses to make further defense. On first observing this peculiar position, I was sure the reptile was dead; but on returning a few minutes later to the box in which I had it, found it looking all right. The same effect followed the repetition of the teasing. When I turned it right side up, it immediately turned back again. Repeated experiment since with these snakes has shown that they even resist with muscular effort a change from their unnatural position.
Many beetles have habits similar to those of the animals named, and, like them, their pretense is overdone. When the Colorado beetle, or potato-bug, falls from the potato-vine on being approached, it nearly always comes to the ground with the feet up.
Many other examples might be given; but the above, I think, are sufficient to show that the theory that in the phenomena under consideration the animals are helpless from fright is untenable. In almost every case the animal manifests consciousness, shows itself cognizant of the situation, and betrays its anxiety to escape. H. L. Roberts.
Lewistown, Ill., February 23, 1889.