+243+. From identity of nature comes the possibility of transformation and transmigration.[444] An Australian of the Kangaroo clan explained that he might be called either kangaroo or man--it was all the same, man-kangaroo or kangaroo-man, and the Australian legends constantly assume change from human to animal and from animal to human.[445] The same belief appears in Africa and North America, and may be assumed to be universal among savages. It survives in the Greek transformation stories and in the werwolf and swan maiden of the European popular creed. It is the basis of a part of the theory of the transmigration of souls.[446] +244+. The relations of early man with animals are partly friendly, partly hostile. A friendly attitude is induced by admiration of their powers and desire for their aid. Such an attitude is presupposed in the myths of intermarriage between beasts and men. It is perhaps visible also in the custom of giving or assuming names of animals as personal names of men, though this custom may arise from the opinion that animals are the best expressions of certain qualities, or from some conception underlying totemistic organization; the general history of savage proper names has not yet been written. Beast tales, likewise, bear witness to man's opinion of the cleverness or folly of his nonhuman brethren, and perhaps originally to nothing more. The distinctest expression of friendliness is seen in certain religious customs spoken of below. +245+. On the other hand, early man necessarily comes into conflict with animals. Against some of them he is obliged to protect himself by force or by skillful contrivance; others must be slain for food. With all of them he deals in such a way as to secure his own well-being, and thus comes to regard them as things subservient to him, to be used in such way as he may find profitable. Those that he cannot use he gradually exterminates, or, at a later stage, these, banished to thickets, mountains, deserts, caves, and other inhospitable places, are excluded from human society and identified with demons.[447]