Vie CONG. INTERN. REPROD. ANIM. INSEM. ARTIF., PARIS, 1968, VOL. II

THE ROLE OF BEHAVIOUR IN REGULATION OF THE REFPRODUCTIVE
FUNCTION IN SOME REPRESENTATIVES OF CANIDAE FAMILY,.
Trut L.N.,Belyaev D.K.
Institute of Cytology and Genmetics,
Siberian Department of the U.S.S.Re
Academy of Sciences,
Novosibirsk.
UsSeSeRe

One of the properties of the wild animal biology,par-
ticularly ,of the beasts of prey,is seasonal reproductive
periodicity.For example,silver foxes bred in captivity for
about 70 years,preserve strictly expressed seasonal pat-
tern of reproduction which isigcharacteristic for this spe-
cies in wild nature.Their sexual activity season ranges
from the last days of January till end of March.The exact
time of sexual activity in the limits of reproductive sea-
son as well as any else reproductive properties(for ins-
tance,fertility)has low heritability,that is the variation
of this character depends mainly upon environmental con-
ditions.This fact as well as absence of variability in
number of sexual cycles during the year,exclude the possi-
bility of hereditary reorganization of the reproductive
function from monoestrous to di- or polyestrous through
direct selection for the mating date.But in the process
of domestication such reorganization took place in many
animal species,particularly in the dog which is sistema-
tically close to the fox.

This paper is dealing with the results of an investi-
gation which showed that loss of seasonal character of re-
production in domestic animals was connected with selec-
tion for the type of defensive behaviour,that is with se-
lection of the most calm,easily tamed animals.

Our first task was to study the character of variabi-
lity of defensive behaviour in relatively wild silver

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