HOMES AND DOMESTIC HABITS 



271 



suffer the loss of their own lives in protecting their off 

 spring from enemies. Many mother birds have the instinct 

 to nutter about a discovered nest crying and apparently 

 broken-winged, thus leading the predatory fox or weasel to 



FIG. 165. Nest and run-way of the p6cket-gopher. 



fix his attention on the mother and to leave the nest un- 

 harmed. This development of parental care and protec- 

 tion of the young reaches its highest degree in the case of 

 the human species. The existence of the family, which is 

 the unit of human society, rests on this high development 

 of care for the young. 



