ISSN 1067-4136, Russian Journal of Ecology, 2016, Vol. 47, No. 4, pp. 392–398. © Pleiades Publishing, Ltd., 2016.
Original Russian Text © E.S. Zakharov, V.M. Safronov, L.P. Koryakina, N.N. Smetanin, 2016, published in Ekologiya, 2016, No. 4, pp. 300–306.
The Ecology of the Red Fox (Vulpes vulpes L.)
in the Middle Lena River Basin
E. S. Zakharov
, V. M. Safronov
, L. P. Koryakina
, and N. N. Smetanin
Institute for Biological Problems of Cryolithozone, Siberian Branch, Russian Academy of Sciences,
pr. Lenina 41, Yakutsk, 677000 Russia
Yakut State Agricultural Academy, ul. Krasil’nikova 15, Yakutsk, 677007 Russia
Department of Hunting of the Sakha Republic (Yakutia)
e-mail: firstname.lastname@example.org, email@example.com
Received March 5, 2015
Abstract—The population of foxes in the central regions of Yakutia has grown by a factor of four to five during
the period from 2000 to 2011–2012, following an increase in the abundance of voles from the genus Microtus.
A total of 130 carcasses of foxes taken in 2007–2012 have been examined. Age- and sex-related variation in
morphological features has been described. The demographic structure of the population has been studied by
estimating animal age from annual layers in the recording structures. Changes in female fertility and involve-
ment in reproduction depending on age and feeding conditions have been analyzed. Changes in the compo-
sition of fox diet caused by long-term population depression in the mountain hare and their effect on the
dynamics of fox abundance have been revealed. Age- and sex-related characteristics of the condition factor
in foxes and sex-related differences in their dietary preferences have been demonstrated.
Keywords: fox, morphology, fertility, sex and age structure, condition factor
DOI: 10.1134/S10674136160 40160
The ecology of the red fox (Vulpes vulpes L.) in
Yakutia has not been studied sufficiently, and there are
no data on the age and sex structure of its population.
This species inhabits the entire forest zone of the
region, but its density and abundance are relatively
low. The basins of the Kolyma, Indigirka, and Vilyuy
are populated more densely, and the yield of pelts from
these regions in the last century reached 8–12.5 pcs.
per 1000 km
, compared to no more than 3–5 pcs. in
the rest of the territory (Tavrovskii et al., 1971). The
abundance of foxes has increased during the past
decade, especially in the Lena–Vilyuy–Amga inter-
fluve. According to the data from the Department of
Hunting of the Sakha Republic, their numbers in cen-
tral regions of Yakutia were 500 ind. in 2000, 2500 ind.
in 2008, 2800 ind. in 2011, and 2100 ind. in 2012. Foxes
have become a common game, but the official hunting
bag size is small, which does not allow the population
density of the species to be estimated from the com-
mercial pelt harvest. At the same time, it has become
possible to study the species in more detail based on
biological samples obtained during the hunting sea-
son. This paper deals with the morphoecological
parameters and abundance dynamics of the red fox in
the Middle Lena basin (Central Yakutia).
MATERIAL AND METHODS
The material for the study consisted of 130 fox car-
casses (61 females and 69 males) taken by hunters in
2007 to 2012. Young animals were identified by the rel-
ative width of the canine tooth canal (Smirnov, 1960;
Zakharov et al., 2013). The age of adult animals was
estimated determined by annual increment layers in
the cementum (Klevezal and Kleinenberg, 1967).
Canine teeth were decalcified in 5% nitric acid and cut
lengthwise using a MS-2 sliding microtome with an
OMT-28-02E freezing table. The sections were
stained by Ehrlich’s hematoxylin. The fertility of
30 adult females was estimated the number of placen-
tal spots in the uterine horns (Kler, 1949).
Analysis of the diet was based on the contents of
42 stomachs. The aboveground phytomass of herba-
ceous plants in the habitats of common voles was
determined by hay harvest method in 1-m
(Obshchesoyuznaya…, 1984). The body condition of
foxes was estimated from the weight of kidney fat
(Shvarts et al., 1968). Information on changes in the
harvest of fox pelts was obtained from official statisti-
cal documents. Data analysis was performed by stan-
dard biometric methods (Rokitskii, 1973).