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Examinations were conducted on four tongues of adult rabbits (Oryctolagus cuniculus). On the basis of observations in a scanning electron microscope (SEM) it was found that fungiform papillae in the rabbit are located on the dorsal surface of the apex and body of the tongue, in the front of the torus of the tongue and on the margins of the tongue. Moreover, fungiform papillae are located laterally in relation to the torus of the tongue and are arranged linearly. Fungiform papillae are distributed among filiform papillae and are separated from them by the interpapillary epithelium. The connective tissue core of fungiform papillae is formed from the body, narrow at the base and wider at the apex and 10-17 crest-like folds arranged around them. On the dorsal surface of the connective tissue core of fungiform papillae there are impressions of taste buds and occasionally traces of lymphatic nodules.
A method for estimating body mass of European rabbitsOryctolagus cuniculus (Linnaeus, 1758) based on tooth dimensions is proposed. Regression models identified significant relationships between the body mass of 87 rabbits and individual tooth length, breadth, product of tooth length and breadth, and whether or not the individual was infected with myxomatosis. Dimensions of 10 of 14 different teeth explained over 80% of variation in body mass, and those teeth were selected as adequate predictors of rabbit body mass. Models were tested using teeth from 16 additional rabbits of known body mass. Body mass, predicted on the basis of 9 of the 10 selected teeth, was statistically indistinguishable from the observed values for all 16 individuals. When myxomatosis infection status of the rabbit was included in the model, all 10 selected teeth yielded predictions statistically indistinguishable from those observed. Prediction errors can be computed permitting statistical comparison of the average predicted value of body mass from different samples of rabbits. The model is useful in estimating rabbit body masses from teeth recovered from feces of predators and it will facilitate testing of hypotheses on size-selective predation. The method was applied to rabbit teeth found in fecal samples from the Iberian lynxLynx pardinus collected over a one-year period. Lynx preyed preferentially upon younger rabbits during the peak breeding period of this lagomorph.
Population structure and adult growth of wild rabbits Oryctolagus cunicuLus (Lin­naeus, 1758) were compared between three habitats, forestry, hill farm and sand dunes, in SE Scotland. The exponentially transformed eye lens weight was used to divide the samples into age classes up to five years old. The forestry and hill farm populations had stable age structures compared with the sand dune population, and the proportion of one year old animals was 58 and 65% compared to only 40% in the sand dunes. The hill farm rabbits were larger than those from the forestry but the pattern of growth was similar. The sand dune rabbits were significantly smaller at all ages and had shorter legs. First year females from the sand dunes were lighter than males of the same age, suggesting that they were not coming into breeding condition, whereas in all the age classes in the other areas, females were heavier than mates. It was suggested that the sand dunes rabbits were restricted in growth as a result of poor nutrition.
We developed broad-scale habitat use models for the distribution of the Iberian hare Lepus granatensis Rosenhaeur, 1856 and the relative abundance of the European wild rabbit Oryctolagus cuniculus (Linnaeus, 1758) in a mountainous area in north-western Spain, the Baixa Limia Site of Community Importance (SCI). For the Iberian hare, the most parsimonious model included average altitude, average slope, scrub-pasture area and length of border between scrublands and forests. Four variables were consequential, 2 of them with a positive sign for the presence of the hare (average altitude and scrubland area) and 2 with a negative one (average slope and length of border between scrubland and forest). For the European wild rabbit the most parsimonious General Linear model obtained included average altitude and scrub-forest edge. Only 2 predictors were consequential, both with a negative sign on the relative abundance of wild rabbits: the average altitude and length of border between scrubland and forest. The models obtained indicated the need of management actions to favour open habitats with suitable vegetation structure, avoiding extensive reforestation. A revision of the current hunting plans in the protected area of Baixa Limia is required.
Exotic prey species can dramatically alter trophic interactions by functionally replacing native prey species. This pattern has been observed in the southern Neotropics, where introduced haresLepus europaeus Pallas, 1778 and rabbitsOryctolagus cuniculus (Linnaeus, 1758) have become the staple prey for native predators. Despite their importance as prey, no data are available on the mass and relative age of the lagomorphs on which native predators feed. We used linear regression models to predict the mass of lagomorphs from their hind-foot length, and investigated the influence of sex, season, and collection site on this relationship. Hind-foot length was a good predictor of body mass for both species and accounted for 58.4 and 71.6% of the variability in body mass for hares and rabbits, respectively. Sex and season significantly influenced the relationship, whereas the effect of collection site was negligible. Hind-foot length was also a good predictor of age class for hares and rabbits, allowing the discrimination between nonreproductive and reproductive classes for both species. Future research can use this method to determine the biomass and age class of exotic lagomorphs consumed by predators.
As European rabbits Oryctolagus cuniculus (Linnaeus, 1758) in SW Spain face high prédation pressure, some antipredator tactics are expected. We examined rabbit group size in relation to the safety of the cover (sparse or dense), and the proximity to shrub cover. Stem density influenced the distance rabbits ventured from shrub; rabbits ventured greater distances when stem density in cover was higher. Rabbit group size was related to the distance to cover; solitary animals remained closer to protective cover, whereas rabbits in groups (> 3 animals) foraged further from cover. These results are consistent with the hypothesis that the formation of rabbit groups is related to defense against prédation, and that group size is influenced by risk of perception.
The diet of the wild rabbit Oryctolagus cuniculus (Linnaeus, 1758) on Alegranza Island (Canary Islands) was studied by microhistological examination of faecal samples. We compared the presence of each food-plant species in the faeces across a year in comparison with plant availability. Two areas were studied, Llano de la Vega and La Caldera. At the first site, Suaeda vera and Chenoleoides tomentosa were the most common plants, while at the latter it was Euphorbia regis-jubae. In general, species belonging to the Chenopodiaceae were most commonly eaten by rabbits. Plants such as Chenoleoides tomentosa and Salsola vermiculata were most important in the diet in every season. Levin's niche-breadth was broader across the seasons in the study site of La Caldera than at Llano de la Vega. Furthermore, this parameter yielded the highest values (broadest niche) during the spring at both sites. Most important plants eaten by rabbits showed green vegetative parts through all seasons. Rabbits selected some plants independently of their availability, even in this reduced insular environment. The feeding behaviour of rabbits in Alegranza, selecting certain species, must have had important consequences on the composition and distribution of the vegetation over the years. This negative effect on island vegetation has been shown to occur on many oceanic islands of the world where rabbits have been introduced.
Functional response and prey age selection have been studied for predator-prey relationships between the Iberian wild cat Felis silvestris tartessia Miller, 1907 and the rabbit Oryctolagus cuniculus (Linnaeus, 1758) through the study of the seasonal wild cat's diet and variations in rabbit availability in south-east Spain. This prey formed 73,7% of the total consumed biomass and was negatively correlated with trophic diversity. The wild cat showed a functional response approximate to Holling's type 2, exhibiting a high dependence on rabbit. The age class preferred was that of the juvenile rabbit, the smallest age class, and such hunting behaviour may be considered to be opportunistic. Results are discussed within the context of the relationship between the great size of this wild cat subspecies and the body size of the principal Iberian prey in Mediterranean areas, the rabbit.
This study analyses differences in European rabbitOryctolagus cuniculus (Linnaeus, 1758) abundance between fragmented and continuous populations and the relative importance of habitat structure (micro- and macrohabitat) and isolation in determining the abundance pattern in fragmented and continuous areas of central Spain. The species was mainly restricted to mediterranean vegetation habitat. In fragmented areas, rabbit abundance was linked to scrubland cover but was not correlated to pasture/cropland cover. The model explained very little of the observed variance. Distance to continuous populations did not improve the model. Stochastic phenomena or unmeasured factors (predation level, soil type) could be acting in this context. Rabbits were more abundant in continuous areas than in fragmented ones. In continuous areas, rabbit abundance was associated with mosaics of pastures, scrublands, and croplands. These habitat features are linked to shelter and feeding requirements of rabbits. The model explained an important part of the observed variance. This supports that management and conservation strategies should be based on the landscape pattern in each situation.
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