Carnivora: the primary structure of the hemoglobin from the silver fox (Vulpes vulpes var., Canidae)

The primary structure determination of the hemoglobin alpha- and beta-chains from the silver fox (Vulpes vulpes var., Canidae) is described. The separation of the chains could be achieved directly from the hemoglobin by RP-HPLC as well as by column chromatography of the globin using carboxymethyl-cellulose. Following tryptic digestion of the chains, the peptides were isolated by RP-HPLC. Amino-acid sequences were determined by Edman degradation in liquid and gas phase sequencers. The peptides could be aligned by homology with human and other Carnivora hemoglobins. Compared to human hemoglobin the alpha- and beta-chains of the silver fox exhibit 24 and 13 amino-acid exchanges, respectively. They differ by one alpha- and two beta-chain replacements from the domestic dog and the coyote. The substitutions affecting contact positions are discussed.     

Geography of sexual dimorphism in the tooth size of the red fox Vulpes vulpes (Mammalia, Carnivora)

Geographic variation in sexual dimorphism of tooth size was assessed for the red fox Vulpes vulpes (Linnaeus, 1758) across the whole northern range of the species. Twenty-one measurements of tooth size and skull length were taken from 2849 specimens (1577 males and 1272 females) originating from 12 Nearctic and 25 Palearctic localities. The index of sexual dimorphism was calculated as a quotient of the mean measure of certain characters in males by the respective mean in females ( M _m/ M _f). In the whole range, the males were larger than females and mean dimorphism index of tooth size ranged from 1.01 to 1.06. On average, the tooth measurements in males were 3.6% larger than in females. The highest dimorphism was observed in the canines. Dimorphism of tooth size was higher in the Palearctic than Nearctic. Statistically significant differences between regions were found for lengths of C¹, C₁ and M₁. In the Palearctic, higher values of the dimorphism indices were observed particularly in the southern parts of the Eurasian range of the red fox and in Great Britain. For a few metrical traits, sexual dimorphism indices presented significant relations to some geo-climatic variables. The geographic pattern of size dimorphism in the red fox seems to be shaped by sexual selection, intraspecific and interspecific competition and population density.     

Acute disseminated toxoplasmosis in a red fox (Vulpes vulpes)

A red fox (Vulpes vulpes) with signs of neurological disease was captured in Fairmount Park, Philadelphia, Pennsylvania (USA). The animal died in captivity and was examined because of suspected rabies. The liver had pale foci up to 4 mm in diameter. Foci of necrosis were associated with Toxoplasma gondii tachyzoites in several organs including liver, lungs and adrenal glands. Rabies antigen and distemper virus inclusions were not detected. The diagnosis of acute disseminated toxoplasmosis was confirmed by immunohistochemical staining.     

Identification of the Tibetan fox (Vulpes ferrilata) and the red fox (Vulpes vulpes) by copro-DNA diagnosis

Studies on feeding habits based on faeces dissecting are imperative to understand the natural history of Tibetan foxes and their functions in the transmission of a lethal zoonotic parasite, Echinococcus multilocularis. However, Tibetan foxes and red foxes live sympatrically on the Tibetan plateau, China. Therefore, the faeces of Tibetan foxes must be distinguished from those of red foxes. We established a diagnostic method to distinguish the faeces of the two species by amplifying a portion of the mitochondrial cytochrome b gene (cytb) and digesting with the restriction enzymes BamHI and SspI, to produce specific diagnostic banding patterns. This PCR-RFLP assay enabled rapid, accurate and easily performed identification and differentiation of the two species.     

Variations of the chromosome number in the red fox (Vulpes vulpes)

The chromosome number in peripheral blood cells of five individuals of Vulpes vulpes (Red Fox) is shown to vary between 35 and 39. This variation is due to loss or gain of the smallest autosome, which it is suggested is heterochromatic and does not have any major influence on the phenotype. This species demonstrates variation in chromosome number both between and within individuals.     

Mitochondrial DNA phylogeography of the red fox (Vulpes vulpes) in northern Japan

Mitochondrial DNA variation in the cytochrome b (cyt b) gene and the control region was examined in the red fox Vulpes vulpes from Japan, with special focus on the population divergence between Hokkaido and northern Honshu. Resultant haplotypes from Hokkaido were subdivided into two distinct groups (I and II), with an average genetic distance of 0.027 for cyt b. Divergence time is roughly estimated to be 1-2 million years ago, given that the conventional divergence rate of the mammalian cyt b gene is 2% per million years. Notably, Group II was only found in Hokkaido, whereas Group I comprised haplotypes from Honshu, Kyushu (Japan), eastern Russia, and Europe, as indicated by a comparison of our own data to the literature. On the other hand, judging from constructed trees, Group I haplotypes from Hokkaido appeared to differ from those from other parts of Japan, i.e., Honshu and Kyushu. This implies that Blakiston's Line, which demarcates the boundary between Hokkaido and Honshu, has been an effective barrier and has allowed the structuring of genetic variation in maternal lineages. Thus, these results suggest that the Hokkaido population, which is sometimes referred to as the distinct subspecies V. v. schrencki, has its own genetic background with multiple migration events and differs from the parapatric subspecies V. v. japonica found in Honshu and Kyushu.     

LHRH and LH release in the red fox Vulpes vulpes L

Pituitary responsiveness to exogenous LHRH was studied in vivo and in vitro in the female red fox, a mono-oestrous species. In vivo, the ability of the pituitary to release LH in response to a single injection of LHRH (2 micrograms/kg) was determined at various stages of the reproductive cycle. The greatest responsiveness is observed during the preovulatory period, the lowest during the luteal phase. During the anoestrus phase, the responsiveness is reduced by more than 50% in lactating females compared to non lactating females. In vitro, dispersed fox anterior pituitary cells were exposed four times to LHRH (10(-9) M), hourly, for 8 min. Pituitary cells were taken from lactating and non lactating females. The cells are not sensitive to LHRH in lactating females but become more and more sensitive after weaning. It is suggested the inhibitory influence of lactation could be the result of prolactin-ovarian steroids-gonadotrophins interactions.     

Pleistocene foxes (Vulpes,Canidae, Carnivora) from the Taurida Cave,Crimea

Doklady Biological Sciences - A mandible fragment and four isolated teeth of the fossil foxes, Vulpes alopecoides (Del Campana, 1913), Vulpes cf. vulpes (Linnaeus, 1758) and Vulpes sp., are...     

Dynamics of spatial relationships among members of a fox group (Vulpes vulpes: Mammalia: Carnivora)

The 'Resources Dispersion Hypothesis' (RDH, Macdonald, 1983) suggests that, for solitary foragers such as the red fox Vulpes vulpes , group formation is dependent on resource distribution heterogeneity. Our data are compatible with this hypothesis. Rodents, which constituted the main fox prey, were heterogeneously distributed in time and space. Six foxes (three males and three females) were radiotracked continuously from February 1989 to October 1990 (20 months) and we observed spatial sharing between one male and two or three females, considered as members of a 'spatial group'. Even though their home ranges overlapped between 30 and 100%, members of the group foraged alone and had very few contacts with conspecifics during the night. Furthermore, they partitioned the common home range so that each fox made exclusive use of foraging patches. In contrast, during the daytime, two to four members of the group were frequently in association in a communal resting place. Such associations were observed all year round; they were durable and dynamic. Their advantages were examined. We suggest that they play a role in the maintenance of social cohesion within the group in providing the opportunity for direct contact between foxes. They might also permit increased security through mutual vigilance during resting.     

Environmental factors influencing the use of habitat in the red fox, Vulpes vulpes

The seasonal variation in habitat selection and its determinants were assessed weekly for a sample of three dog-foxes and two vixens in an ecotonal area of the Tuscan coast, in Italy. The most utilized habitats were the maquis (scrubwood), meadows and pinewood. In the cold season the maquis was preferred to any other habitat, but in the warm months foxes made extensive use of meadows. On the other hand, no clear seasonal pattern of use was detectable for the pinewood. Food habits showed a seasonal variation: juniper berries were the staple food, forming by far the greatest part of the diet during the whole study, except in late spring through midsummer, when beetles and grasshoppers predominated. Availability indices for each main food category were calculated on a weekly basis. Distribution of juniper berries was found to be clumped, whereas insects were dispersed. It was also assessed that the former occurred almost entirely in the pinewood, while the latter inhabited mainly meadows and, to a lesser extent. the pinewood. Measures of fox activity in the three habitats were also taken. The fox diet correlated well to the seasonal abundance of the important food resources, which in turn was significantly correlated to meteorologic factors (temperature, number of rainy days). Surprisingly, the seasonal activity in the pinewood was inversely correlated to local food availability, i.e. juniper berries. This can be explained by the clumpedness of this food resource which, when abundant, allows foxes to become quickly satiated and to retreat to other, more preferred habitat such as the maquis. Such results caution against assuming that extensive time spent in a habitat is an indication of proportional feeding dependence on it.     

Disseminated bovine tuberculosis in a wild red fox (Vulpes vulpes) in southern Spain

A wild-caught, adult red fox (Vulpes vulpes) from Do?ana National Park (southern Spain), in very poor condition, died during anesthesia. At necropsy, the submandibular, retropharyngeal, mediastinal, axillary, mesenteric, and popliteal lymph nodes were enlarged, and the right submandibular and mesenteric lymph nodes had hard, white-colored concretions (calcifications). Multiple white pinpoint foci were observed in the lungs, and abscesses were present in the left dorsal lung lobes. No lesions were seen in tonsils, liver, or spleen. On histopathology multiple tuberculous granulomas, with Ziehl-Neelsen-positive bacilli, were observed in the lung, and multifocal necrotic areas with calcification were present in the submandibular and mesenteric lymph nodes. Nucleic acid amplification from lymph node samples demonstrated the presence of mycobacteria belonging to the Mycobacterium tuberculosis complex. One strain was isolated by culture and identified as Mycobacterium bovis. The suspected route of infection was oral, probably after repeated scavenging of infected wild ungulate carcasses. This is the first report of generalized bovine tuberculosis (bTB) in a wild canid. This finding raises concerns about bTB as a disease risk for protected species, livestock, and humans in Mediterranean Spain.     

Fecundity and egg output by Toxocara canis in the red fox, Vulpes vulpes

The role of the red fox Vulpes vulpes in the dissemination of eggs of Toxocara canis into the environment is considered with reference to female worm fecundity and egg output in the faeces of infected foxes collected from four localities in southern England. A significant positive correlation was found between female worm size and the number of eggs in the uterus but there was no significant relationship between T. canis worm numbers and egg output in fox faeces. Reliable estimates of worm burdens in foxes could not, therefore, be determined from faecal egg counts alone. The highest mean egg output of 2145.0 epg recorded from adult foxes indicated that fox cubs are not necessarily the main sources of environmental contamination with T. canis eggs. Saturated magnesium sulphate was found to be a more effective flotation solution than zinc sulphate and sodium chloride for recovering eggs from fox faecal samples.