Changes in nest building behaviour in multiparous rabbits

This study deals with the effects of repeated litter production on one aspect of nest building behaviour, quality of nest. The results in the files of the Rabbit Genetics Laboratory, R. B. Jackson Memorial Laboratory, Bar Harbor, Maine,on over 800 rabbits of different races and sublines were utilised. From these extensive data, a group of 84 rabbits, selected on the basis of having produced four litters, were analysed. They were members of three different races and two sublines as follows: Race X, Race AcEp, Race III, and sublines IIIc and IIIr².

The hypothesis tested in the analysis was that there would be systematic improvement in performance with each of the four litters in the quality of nest production. Analyses of variance were made, which support the following conclusions: (1) a confirmation of the previous findings by Sawin & Crary (1953) of significant race differences; (2) significant improvement in quality of nest over the first four litters produced; (3) a good approximation of the functional relationship of nest rating to litters, as a linear one. The interpretation of this relationship is quite complex. Both learning and endocrine changes are possible hypotheses to be considered though no conclusion concerning the underlying mechanism is possible at this point. Further analyses and experimentation will be necessary to gain an understanding of this phenomenon.