2IO Report S.A.A. Advancement of Science. 



From the behaviour of the ostrich chicks it may be assumed 

 that on rushing towards them the first instinct to assert itself was 

 that cf flight, and the birds scattered. Then extreme fright or terror 

 supervened, and brought about a general nervous collapse of the 

 chick, as a result of which it flopped down. From this condition 

 of nervous collapse it only slowly recovered. In insects, as, for 

 instance, in many beetles, it is often found that a sudden touch will 

 bring about the same response, though it is very questionable as to 

 how far what we know as fear is here concerned. It seems to be 

 little more than a reflex reaction which has proved itself useful to the 

 animal's ancestors, and thereby been preserved and more perfectly 

 developed by natural selection. 



Death-feigning in the ostrich chick has evidently a greater 

 significance than that of merely giving to the animal the appearance 

 of being dead and inert, in the same manner as in an insect. The 

 principle of protective resemblance is also involved. Every ostrich 

 farmer knows the extreme difficulty of finding a brood of ostrich 

 chicks once they scatter in the bush and crouch down. After a pro- 

 longed search he will secure only a few of those immediately near 

 him, and then return for a second attempt, when the birds have again 

 gathered round the parents. The peculiar black and brown striping 

 of the neck, found only in chicks, and the mottled black and brown 

 natal plumage harmonize most closely with the surroundings when 

 the chicks are recumbent upon the ground. 



The chicks appear to get beyond the instinct of death-shamming 

 very early. The ones just mentioned never again displayed the 

 reaction after being brought home and reared by hand ; and it seems 

 to be rarely resorted to by incubated chicks artificially reared. Under 

 some circumstances, however, very young birds, say to one month old, 

 will fall flat from almost any object or noise which suddenly startles 

 them, and this applies to tame chicks as well as to wild or nearly 

 wild ones. Also as the chicks get older the collapse is not so complete 

 nor does it continue for so long a period as at first ; for frequently after 

 a bird has crouched down and one makes towards it, the creature will 

 spring up and make off, perhaps to drop a second time if hard 

 pressed. The experience of farmers is that by the time the chicks 

 are a month or more old they resort more freely to running when 

 alarmed, and only crouch when hard pressed or very suddenly 

 startled. 



We mav now consider if there is any evidence for the instinct 

 being continued into the adult stage of the ostrich. In a general 

 way it is found that when an ostrich is alarmed it takes to running, 

 and even the fleetest horse is incapable of keeping pace with it so 

 long as the pursued continues in a straight course. Once fully 

 started, the bird probably never has recourse to the true, death- 

 shamming instinct, but will continue its course as long as its strength 

 lasts, and onlv fall flat when exhausted, often never to rise again. 

 In the days of wild ostrich hunting the birds were thus frequently 

 driven to death with a horse. The instinct of flight, however, is not 

 resorted to under all circumstances bv adult birds. Instances are 



