Biology_of_Mustelids_Vol_1.pdf

There is no doubt that the male takes some part (not necessarily
active) in the rearing of the young.
The young remain with their parents
for a long time. We often observed in late autumn, in September and October,
old weasels hunting with full grown young.
Summary
The author described two different subspecies of weasel which occur
in the Archangelsk Region of USSR: Mustela nivalis nivalis Linnaeus, 1766,
and Mustela nivalis pygmaea J.A. Allen, 1903.
The external characters of
these SUbspecies are established, and their geographical distribution (see
Fig.1) and their densities (Fig.2).
For the external measurements of both SUbspecies see Table 1.
For
comparison the external measurements of weasels according to Ognev (1935)
are shown in Table 2.
Skull measurements in mm are as follows :
Mustela nivalis nivalis (n = 63): Condylobasal length aa 31.2-38.0, ~~ 31.0-32.8;
zygomatic width aa 17.0-19.5, ~~ 15.0-18.0; mastoid width aa 14.5-17.8,
~~ 13.5-17.5; length of upper tooth row aa 9.3, ~~ 8.8 mm.
Mustela nivalis pygmaea (n = 22): Condylobasal length aa 32.0-34.5, ~~ 30.2­
33.0; zygomatic width aa 16.6-17.5, ~~ 14.6-17.2; mastoid width aa 15.3-16.1,
~~ 14.6-15.6; length of upper tooth row aa 8.8, ~~ 8.4 mm.
The author also studied,over 30 years, some aspects of ecology and
biology of the species in the Archangelsk Region.
Many observations show
that the number of weasels increases in direct correlation with the number of
small rodents.
The author assumes that the ermine (Mustela erminea Linnaeus, 1758)
probably does not do well in competition for food with Mustela nivalis, because
in the areas where the weasels occur
in a large number, the number of the
ermine is relatively very small.
The weasel's diet consists mainly of voles and mice, occasionally
including squirrels, small Insectivores, hares and birds.
The data on the