ved too.It was found that some females which had no lit-
ters or cannibalized them and thus avoid lactation,had
different stages of sexual activity in the middle of
April,and one of the females exhibited real oestrous on
the 8—10tn of April.No one of the control,non-selected
for behaviour females,independently of their reproduction
during normal breeding season,exhibited any sexual chan-
ges either in autumn or in spring.It has been found 15
tamed females with symptoms of oestrous activity without
the breeding season out of 200 females being under expe-
riment for many years.Genealogical analysis of these 15
females snowed that they were representatives of 5 most
easily tamea strains of animals.

Thus,basing upcn all these facts,one may consider
that female foxes descending from strains selected for
tameness 10 years long,exhibit distinct changes of repro-
ductive properties,which are expressed in pronounced ac-
tivation of sexual system without the reproductive season
characteristic for these animals.

1680