Sociality, time and space in a sparse population of rabbits (Oryctolagus cuniculus)

This 10-year study describes a sparse population of rabbits ( Oryctolagus cuniculus ) living in small, semi-isolated groups on river flats with some scrub in an otherwise forested valley. The rabbits lived above ground in the scrub by day and fed in the open at night. They bred in isolated 'stops' dug in the shingle often far from suitable grazing for the young. Many stops collapsed, killing the young. Home ranges were recorded by radio telemetry. Bucks had larger ranges than does and spent less time in the scrub. Adults of both sexes were sedentary for life. Some bucks travelled > 500 m at night. Most ranges were too large to be defended strictly; night feeding grounds were often communal. In the evening, adult rabbits spent 44% of the time feeding and 33% inactive. Social interactions were frequent. At all seasons, in the evening most adult rabbits were seen singly or as pairs. Pairs seldom remained intact for > 12 months even when both partners were alive. The buck of the pair was usually older than the doe because bucks outlived does. The adult survival rate was about 0.80 for bucks, 0.55 for does. Four bucks lived for > 7 years. Few young survived for long after leaving the nest; many were killed by predators. Dungheaps, used for 60% of the droppings, were concentrated near the scrub where rabbits congregated in the evening. The behaviour of these rabbits differed in many ways from that of rabbits in enclosures or at higher density in the wild.     

Fine-scale genetic structuring in a natural population of European wild rabbits (Oryctolagus cuniculus)

The genetic structure of a free-living tagged population of European wild rabbits (Oryctolagus cuniculus) was investigated for two consecutive years (1990 and 1991) using 10 polymorphic microsatellite loci. A specific social behaviour, the formation of stable breeding groups, influenced the genetic structure of the population. These breeding groups were shown to constitute genetically differentiated units with low levels of gene flow between them. The average relatedness among members of a social group was higher than within the population as a whole. As a result of female philopatry coupled with male-biased natal dispersal, the relatedness of females was higher than that of males, both within social groups and in the whole population. Furthermore, the average relatedness of females within groups was twice the relatedness of females between groups. This study reveals marked fine-scale, intrapopulation genetic structure, which is attributable to the social behaviour of the European wild rabbit.     

The incidence of helminth parasites from the wild rabbit Oryctolagus cuniculus (L.) in eastern Scotland

Samples of wild rabbits were collected each month over the six-year period 1977-82 and their intestines and abdomens examined for helminths. Three species of nematode, four of cestode and one trematode were found. Graphidium strigosum was recorded in 33% of the 786 rabbits, Trichostrongylus retortaeformis in 79%, Passalurus ambiguus in 14.2%, Cittotaenia pectinata in 37%, C. denticulata in 11%, Coenurus pisiformis in 3%, Cysticercus serialis in 0.1% and Fasciola hepatica in 0.1%. G. strigosum and P. ambiguus infections were greatest in the older heavier animals whereas juvenile rabbits had the heaviest T. retortaeformis nematode burdens. Seasonal fluctuations were observed in G. strigosum, T. retortaeformis, P. ambiguus and Cittotaenia denticulata. The sex and reproductive state of the female rabbit did not have any significant effect on either the nematode or cestode worm burdens. Myxomatosis was shown to significantly increase the worm burden of T. retortaeformis and raise that of P. ambiguus. No nematode or cestode from domesticated animals were recovered and it was concluded that since F. hepatica was found only once rabbits did not constitute a serious hazard to the farm animals grazing the area.     

Salmonella ochiogu: experimental infection of laboratory rabbits (Oryctolagus cuniculus)

Oral infection with Salmonella ochiogu resulted in the manifestation of clinical salmonellosis in laboratory rabbits. Infection was associated with septicaemia, anaemia and terminal pneumonia. Organisms were excreted in the faeces on the first day post-inoculation, and cultures of most visceral organs revealed widespread dissemination. This serotype appears to be highly pathogenic for rabbits.     

Outbreak of sarcoptic mange and malasseziasis in rabbits (Oryctolagus cuniculus)

An outbreak of combined Sarcoptes and Malassezia spp. infection was diagnosed in a rabbitry. About 20 (4%) of 500 rabbits were affected. Two 6- to 8-month-old female Holland Lops rabbits were submitted to the Tifton Diagnostic & Investigational Laboratory at The University of Georgia for complete necropsy. Gross lesions consisted of marked multifocal areas of alopecia, crusting, and dermatitis around the eye and on ears, nose, lips, neck, abdomen, feet, and external genitalia. Histologic examination of the skin revealed epidermal acanthosis with marked parakeratotic hyperkeratosis and cross sections of embedded mites consistent with Sarcoptes sp. and budding yeasts consistent with Malassezia sp. To the best of the author's knowledge, this is the first case report of combined Sarcoptes and Malassezia spp. infection in rabbits.     

Dynamics of spermatogenesis in rabbits Oryctolagus cuniculus

The rabbit spermatogenesis was investigated in dynamics with morphology of testicular tissues being analysed. Allocation characteristic of spermatogenous epithelium cells in spermatic ductules was examined for 19 age groups of rabbit males aged from 10 days to 12 months. The availability of three types of spermatogonia A, intermediate and B was analysed. In has been determined that the age from 10 days to 4 weeks is optimal for isolation of testis stem cells, when rabbit spermatogonia are represented by spermatogonia of A-type only.     

Seasonal variation in gut morphology in wild rabbits (Oryctolagus cuniculus)

It is shown experimentally that diet composition affected the sizes of several digestive organs in juvenile rabbits collected from the wild. Stomach weight, small intestine volume and colon length were larger in rabbits reared on diets higher in fibre. Small intestine weight, however, was lower.
Analysis of natural variation in wild adult rabbits showed that all digestive organs (except for the appendix) were larger in rabbits living on chalk soils than in those living on sand or clay. Seasonal variation was more marked in males than in females, probably because of the sexes' different breeding requirements. Thus most male digestive organs were smaller between December and June than at other times of year. Female digestive organs did not show this pattern, and were largest in May/June, when the demands of pregnancy and lactation are highest. However, food quality may have been important too. Food quality is probably highest in April, and most digestive organs were then smallest (both sexes). The dry weights of stomach and small intestine did not fit these patterns. Stomach weight increased with the presence of the nematode parasite Graphidium strigosum and small intestine and caecal volumes with the presence of cestodes. Numbers of nematodes (Trichostrongylus retortaeformis and Passalurus ambiguus) in the caecum or colon, however, had no effects on organ sizes.
Data are presented on variation in intensity and prevalence of these helminth parasites with season and soil type.     

Cryptosporidium cuniculus in the rabbit (Oryctolagus cuniculus)

Cryptosporidium cuniculus was identified by light and electron microscopy in two apparently healthy rabbits. Organisms were firmly attached at the brush borders of intestinal epithelial cells. Cellular alterations were minimal, consisting of elongation and shortening of microvilli adjacent to the attachment sites of organisms. Various developmental stages of cryptosporidium were identified by electron microscopy.     

Pelvic visceral arteries of rabbits (Oryctolagus cuniculus)]

40 pelvic preparations of rabbits (oryctolagus cuniculus) were bilaterally studied by dissection under the stereomicroscope and angiography. The arterial pattern of the pelvis, i.e. origin and branching of the umbilical, urogenital and internal pudendal arteries (visceral branches), is described. The main characteristics observed are as follows: (1) The umbilical artery is permeable in adults and gives origin to the cranial vesical artery and a caudal branch that irrigates the pelvic urogenital organs and, eventually, the rectum, with six patterns of branching in both sexes. (2) Usually, the urogenital artery is the continuation of the visceral branch of the internal iliac artery. In 1 animal, unilaterally, it arises from the median sacral artery. In 12 animals (6 bilaterally and 6 unilaterally) the urogenital artery is absent. When present, it forms two branches, a cranial and a caudal one, that irrigate of the urogenital organs in both sexes. (3) The internal pudendal artery is the direct continuation of the internal iliac artery and gives to rise to some visceral branches that irrigate the penis, bulbourethral gland and rectum (with six patterns of branching) in males, and the vagina, clitoris and rectum (with three patterns of branching) in females.     

Distribution and use of burrows and tunnels ofChaetophractus villosus (Mammalia, Xenarthra) in the eastern Argentinean pampas

Burrows and tunnels built byChaetophractus villosus (Desmarest, 1804) (hairy armadillo) were studied in a farming area located in the Argentinean pampas, Buenos Aires Province, Argentina. Fifty-six structures were selected and carefully excavated for this study. Data on diameter, form, and orientation of the entrance, angle, length, and depth of the galleries, and spatial distribution of the structures were recorded. The structures were separated into two types: simple and complex, both located in high terrain. Simple structures are shorter than complex ones and are built when animals are in search of food or as temporary shelters. Complex structures are built as home burrows. The orientation of the entrances of both kinds of burrows is related to the prevalent wind direction.     

Modeling the distribution of wild rabbits (Oryctolagus cuniculus) on a Mediterranean island

The European rabbit (Oryctolagus cuniculus) is a widely distributed mammal with an often contradictory ecological role, imposing the need for population management. Sound management requires an in-depth understanding of the complex species–habitat relationships. In this study, CART analysis was employed to identify the most important environmental and anthropogenic factors affecting the spatial distribution of wild rabbit on Lemnos Island, northeastern Aegean Sea in Greece. On Lemnos, this species is considered an agricultural pest due to its overabundance resulting from the long-term absence of viral diseases, limited predation pressure, and lack of effective management. The study was carried out during the summer of 2008 by surveying rabbit densities in 181 2 × 2-km squares. Seven environmental and 14 anthropogenic variables, measured at two spatial scales, were used as explanatory variables. Soil hardness was the most influential variable, dividing the island into two distinct areas, namely the rabbit-poor areas with hard rocky soils and the rabbit-rich areas where soft soils prevail. In the former, the presence of a sharp relief can lead to complete absence of the species, while a combination of gentle relief, low altitudes, and low presence of arable land can lead to moderate rabbit density. In the latter, human-caused disturbance can reduce the number of rabbits, while a high density of ecotones and streams and a high presence of riparian vegetation can increase population densities to its highest levels observed. Our findings can formulate a scientific basis for the development of an effective management strategy for its population control.     

Disseminated staphylococcal disease in laboratory rabbits (Oryctolagus cuniculus).

The pathologic findings in 13 cases of staphylococcal disease in New Zealand white rabbits were described. Subcutaneous abscesses and embolic pyemic abscesses in kidney, heart, brain, and lung were found. Conjunctivitis, rhinitis, otitis media, and fibrinous pneumonia also occurred. One rabbit had a valvular endocarditis. Staphylococcus aureus, coagulase-positive, and fermenting mannitol were isolated from the lesions described. Staphylococcal disease was diagnosed in 13 of the 171 (7.6%) rabbits necropsied during a 3-yr period. Disseminated staphylococcal lesions were observed only in rabbits during this time.     

Prevalence of Toxoplasma gondii antibodies in rabbits (Oryctolagus cuniculus) from Mexico

Antibodies to Toxoplasma gondii were determined by indirect enzyme-linked immunosorbent assay in serum samples from domestic rabbits from 3 rabbit farms in Mexico. Antibodies to T. gondii were found in 77 (26.9%) of 286 animals. On the farm with the higher rearing standards, the seroprevalence was 18.7%, whereas on the farm with medium standards and another managed by a family, seroprevalence was 39.7 and 33.3%, respectively. This report is the first report concerning the prevalence of antibodies to T. gondii in rabbits from Mexico. Although the prevalence found in the present study is within the range reported for other countries, 2 of the farms revealed a relatively high prevalence, which was probably associated with the presence of cats inside rabbit houses.