Cytogenetics of albinism in polecats of the genus Putorius (Carnivora, Mustelidae)

Karyotypes of two ferret species, Putorius eversmanni (2n = 38) and P. putorius (2n = 40), differ in a single Robertsonian rearrangement, resulting in decreased chromosome number in P. eversmanni. Interspecific hybrids from crosses between P. eversmanni and domesticated albino ferret P. putorius furo are fertile. Hybrid individuals have a chromosome set 2 = 39. Analysis of offspring from crosses of these hybrids showed that albinism is a recessive character. Offspring obtained from crosses between interspecific hybrid ferrets and between these hybrids and parental species was subjected to chromosome analysis. A statistically significant correlation was observed between the chromosome number and albinism. As a rule, albino hybrids have a chromosome number 2n = 40. This suggests that the locus, controlling albinism, is located at one of the two pairs of acrocentric chromsomes involved in Robertsonian rearrangement. The rare occurrence of albino hybrids with 2n = 39 may be attributed to recombination. According to our data, recombination probability is less than 0.5 which indicates that the albinism locus located near the centromere. Possible extrapolation of the data obtained for ferrets to other Mustelidae is discussed.     

Mink (Mammalia; Carnivora; Mustelidae): correction of a widely quoted error

Since the European Mink Mustela lutreola and the introduced American Mink M. vison are now sympatric in some parts of the former's native range, and since the two species are similar in appearance, ecology, and behaviour, a need has arisen for a simple way of discriminating live specimens of the two species in the field. Many publications, particularly field guides, have recommended diagnosis on the basis of the presence of white hair on the upper lip of the European species, and its absence in the American species. This is a mistaken suggestion, which should be avoided by authors. American Mink seldom if ever show the large white moustachial bands seen in some European Mink, and may indeed have no white hairs on the upper lip; but white patches of lesser size are common enough to be a possible cause of confusion.     

A comparative analysis of the complete mitochondrial genome of the Eurasian otter <Emphasis Type="Italic">Lutra lutra</Emphasis> (Carnivora; Mustelidae)

Otter populations are declining throughout the world and most otter species are considered endangered. Molecular methods are suitable tools for population genetic research on endangered species. In the present study, we analyzed the complete mitochondrial genome (mitogenome) sequence of the Eurasian otter Lutra lutra. The mitochondrial DNA sequence of the Eurasian otter is 16,505 bp in length and consists of 13 protein-coding genes, 22 tRNAs, 2 rRNAs, and a control region (CR). The CR sequence of otters from Europe and Asia showed nearly identical numbers and nucleotide sequences of minisatellites. Phylogenetic analysis of Mustelidae mitogenomes, including individual genes, revealed that Lutrinae and Mustelinae form a clade, and that L. lutra and Enhydra lutris are sister taxa within the Lutrinae. Phylogenetic analyses revealed that of the 13 mitochondrial protein-coding genes, ND5 is the most reliable marker for analysis of phylogenetic relationships within the Mustelidae.     

Detailed lipid analysis of yolk platelets of amphibian (Bufo arenarum) oocytes

Yolk platelets, the principal components of amphibian oocytes, have been generally considered as material reservoirs. Their biochemical composition and function during oogenesis and early development have not been fully elucidated. The aim of this study was to carry out a lipidic characterization of yolk platelets from full-grown Bufo arenarum oocytes. Ovarian oocytes were manually obtained and the subcellular fraction was isolated by centrifugation at low velocity. Lipids were separated by thin-layer chromatography. For compositional analysis, they were derived by methanolysis, being identified and quantified in a gas-liquid chromatograph. Phospholipid content indicates that phosphatidylcholine and phosphatidylethanolamine are the main phospholipids followed by phosphatidylinositol, sphingomyelin, phosphatidylserine, and phosphatidic acid. Phospholipidic profile is similar to that in whole oocytes except for the absence of diphosphatidylglycerol in yolk platelets. Oleic, palmitic, and linoleic acids are the main fatty acids in phosphatidylcholine, and oleic acid is the principal one in phosphatidylethanolamine. In phosphatidic acid, palmitic, estearic, palmitoleic, and oleic acids represent 68 mol% of the total acyl groups. Phosphatidylinositol, enriched in arachidonic acid, is the most unsaturated phospholipid while sphingomyelin shows the lowest unsaturation index. The acyl group distribution in triacylglycerols is similar when yolk platelets and whole oocytes are compared. Polar and neutral lipids of yolk platelets determine the lipidic profile of the whole oocyte. The presence of unusual fatty acids as 14:0, 15:0, 15:1, 17:0, and 17:1 in phospholipids and triacylglycerols may indicate an oxidation mechanism different from beta-oxidation in yolk platelets and/or a structural and functional relation with mitochondria. Given that yolk platelets in amphibian oocytes may act in a dynamic fashion in development, their role should be reconsidered.     

The status of the Badger Meles meles (L., 1758) (Carnivora, Mustelidae) in Europe

The Eurasian Badger occurs throughout the Palaearctic, and in all states of Europe west of the border with the former Soviet Union. Within this area it is absent only from the arctic zones, high-altitude areas, and some islands. The Badger is currently a protected species in the UK, the Irish Republic, Spain, Portugal, Italy, Belgium, the Netherlands, Albania, Greece, Estonia, Luxembourg and Hungary, but Luxembourg and Hungary are to reconsider protected status. Elsewhere, the species is either considered as small-game or as a pest, hunting being regulated by closed seasons. At present Finland and Burgenland (Austria) afford protection to breeding females, whilst Bulgaria, Macedonia and the Austrian Bundesländer of Steiermark and Salzburg permit Badger hunting throughout the year. Where the species is protected, provisions usually exist for the removal or culling of ‘pest’ individuals. The official European game-bag currently totals about 118,000 Badgers, but poaching is common, particularly in the UK and Ireland. Published population estimates, coupled with national population minima obtained by extrapolation from game-bag statistics, indicate a minimum European Badger population of 1,220,000; the true figure may exceed this considerably. Badger populations appear to be either stable or increasing throughout much of Europe, although no data are currently available for the populations of Greece, Italy, Spain, Croatia, Bosnia-Hercegovina and Portugal. Badgers are uncommon in the Netherlands, Estonia, Belgium, the Slovak Republic, and possibly Poland. Only the populations of Albania and possibly of some parts of the former Yugoslavia appear to be decreasing. The Dutch population remains at considerable risk, despite modest recent increases. The population status of the endemic sub-species of Crete and Rhodes remain uncertain and require urgent clarification. A series of management recommendations are proposed to improve the status of the Badger in Europe.     

Development of survival skills in captive-raised Siberian polecats (Mustela eversmanni) II: Predator avoidance

We exposed naive Siberain polecats (Mustela eversmanni) (aged 2, 3, and 4 months) to a swooping stuffed great horned owl (Buho virginianus) and a stuffed badger (Taxidae taxus) mounted on a remote control toy automobile frame. The first introduction to each was harmless, the second was accompanied by a mild aversive stimulus, the third (1 day after attack) was harmless, and the fourth (30 days after attack) was harmless. Alert behavior increased after a single attack by either predator model. Escape responses of naive polecats did not differ between ages when exposed to the badger, but 4 month old polecats reduced their escape times after a single badger attack. When exposed to the swooping owl, naive 4 month old polecats redponded more quickly than the other two age groups, and 3 and 4 month old polecats reduced escape times after a single owl attack. This indicates an innate escape response to the owl model at 4 months of age, and a short-tert ability to remember a single mild aversive encounter with the badger and owl models at 3 or 4 months of age.     

Development of survival skills in captive-raised Siberian polecats (Mustela eversmanni) I: Locating prey

Captive-raised mustelids appear to have a rudimentary capacity to kill prey, but the skills necessary for locating prey may be eroded during captivity. We tested the maturational component of prey-searching behavior with captive-raised Siberian polecats (Mustela eversmanni) by subjecting polecats to a simulated prairie dog colony of 6 burrows within a 200 m² arena. Ten naive Siberian polecats at ages 2.5, 3.5, and 4.5 months (30 total) were deprived of food for 12 hours. A dead prairie dog was placed in 1 prairie dog burrow and the other 5 were empty. A single Siberian polecat was released onto the colony shortly before sunset and its movements monitored from an observation tower. Older Siberian polecats located prey significantly quicker than younger polecats, but all age groups spent a great deal of time in surface activity not directed toward a burrow. When Siberian polecats were about 10 months old, all burrows in the arena were plugged with dirt including the burrow with the prairie dog. In this winter test, Siberian polecats located the prey but still spent a great deal of time in non-burrow directed surface activity. Economical use of surface time, with a low amount of non-burrow directed behavior, would presumably reduce the risk of predation for hunting polecats.     

Sexual selection in a polygynous rodent (Ctenomys talarum): an analysis of fighting capacity

The South American subterranean rodent genus Ctenomys (Caviomorpha: Octodontoidea), which uses both claws and teeth to dig, shows striking morphological adaptations to its specialized mode of life. Among other traits, the genus has evolved a powerful jaw musculature and procumbent incisors that are used for dento-excavation. Behavioral observations indicate that these traits are also used during male aggressive encounters, which characterize the polygynous mating system of one of the species of the genus, Ctenomys talarum. A question emerges about sexual selection: could it have induced further changes in traits primarily evolved as adaptations for digging? To address this issue, we studied functional and morphological attributes of the jaw and incisors in specimens of C. talarum. Incisor bite forces were measured on wild females and males from a local population (Mar de Cobo; Buenos Aires Province) by means of a strain gauge load cell force transducer. Museum specimens coming from the same population were studied to assess anatomical attributes of both sexes. Since this species exhibits dimorphism in body size, the possible effect of body mass on the studied traits was analyzed. Males and females showed significant differences in biting performance and mandibular width, but when size was taken into account these differences disappeared. However, other dimorphic traits can vary with a certain independence with respect to size, particularly the 2nd moment of area of the incisors and, to a lesser extent, incisor procumbency. The former geometrical parameter, which is proportional to the bending strength, was highly dimorphic. This fact suggests that, during aggressive encounters between males, biting would place large bending loads on the incisors.     

Sexual dimorphism of marbled polecat Vormela peregusna (Carnivora: Mustelidae)

Analysis of morphometric variation in 26 cranial characters were studied in 85 individuals of marbled polecat Vormela peregusna from Turkmenistan demonstrated a low level of sexual dimorphism in the species. The properties of sexual dimorphism in marbled polecat are discussed in terms of available hypotheses of sexual dimorphism in carnivores.     

The ecological significance of resting sites and the seasonal habitat change in polecats (Mustela putorius)

The daytime resting sites of 13 radio-tracked polecats ( Mustela putorius ) were recorded in a mountainous and a lowland study area in Switzerland. Information on breeding sites was collected from questionnaires distributed throughout the country. At all resting sites, the polecats were completely invisible from more than a metre distant. During summer, when polecats mainly live in forests, individuals used many different hiding-places (e.g. small self-dug burrows, woodpiles, heaps of branches and dry leaves, dense vegetation). Such places were used for short periods, and then abandoned. Above ground, the polecats sometimes built nests of dry grass or moss. In winter, the polecats slept mainly inside barns, stables and other buildings. These resting sites were changed less frequently. In rainy weather throughout the year, subterranean places were preferred. Breeding polecats were often found inside houses, and obviously did not avoid human presence.
The importance of different types of resting sites for polecats is discussed. In summer, the quality of a resting place is of less importance than its distance from the foraging area, but in winter, warm resting places are essential and buildings are therefore considered an important resource for polecats in Switzerland. The seasonal habitat change can more readily be explained as a consequence of thermoregulatory problems than of food availability, and the distribution of polecats in Switzerland may be affected by the availability of suitable winter resting places. The northern limit of polecat distribution and its historical changes can be explained by the changing availability of human buildings which provide winter resting sites.     

Experimental infection of domestic ferrets (Mustela putorius furo) and Siberian polecats (Mustela eversmanni) with Yersinia pestis

Eight domestic ferrets (Mustela putorius furo) and two Siberian polecats (M. eversmanni) were inoculated subcutaneously with 12 to 1.2 x 10(7) Yersinia pestis originally isolated during an epizootic of plague in white-tailed prairie dogs (Cynomys leucurus) near Meeteetse, Park County, Wyoming (USA) in 1985. None of the ferrets or polecats developed clinical signs of disease which suggested that black-footed ferrets (M. nigripes), a congener, also would be resistant to plague. All animals receiving greater than or equal to 1.2 X 10(3) organisms produced serum antibodies detected by the passive hemagglutination test with titers peaking at 1:1,024 and remaining positive until at least 219 days postinoculation. Sera collected from 12 free-ranging black-footed ferrets near Meeteetse in 1984 and 1985 were negative for antibodies against Y. pestis. Prevalence of antibodies against Y. pestis was high in other carnivores collected from the same area in 1986.     

The femur of extinct bunodont otters in Africa (Carnivora,Mustelidae, Lutrinae)

This study compares fossil femora attributed to extinct African bunodont lutrines with extant mustelids and ursids to reconstruct locomotor behavior. Due to the immense size differences among taxa, shape data were used to compare morphology. Based on morphological differences, the fossil femora are suggested to belong to different taxa with different locomotor abilities and habitat preferences. The Langebaanweg femur is the oldest and has a typical mustelid morphology suggesting that it was a locomotor generalist like most mustelids. The West Turkana form is more like extant nonbunodont otters, but much larger, and may have belonged to a semiaquatic taxon. The enormous Omo femur shares some features with truly aquatic taxa (e.g., Enhydra) and is the most likely to have been fully aquatic. The same may hold true for the Hadar species as it is most similar to that from the Omo. If these femora truly belong to bunodont lutrines, then they are more diverse in postcranial morphology than in dental morphology.     

Interval timing in Siamese fighting fish (Betta splendens)

The present study evaluated the temporal performance of Siamese fighting fish (Betta splendens) given short-term exposure to four fixed interval (FI) schedules of reinforcement, FI 30, 60, 120, and 240 s, during which a reinforcer (mirror image) was given for the first response (swimming through a hoop) after the interval requirement had elapsed. Response levels were generally low early in an interval and increased as the interval elapsed; wait times and break points in an interval increased with increases in the FI requirement. The results were similar to that obtained with other species and different types of responses and reinforcers, and demonstrate that the procedure is a feasible method for studying interval timing in fish.