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Moving and standing in trees impose multiple problems to arboreal mammals. Among them, the major ones are the negotiation of slender terminal branches and of large vertical supports. Both microhabitats are important as they have been linked alternatively to the evolutionary loss of claws in early primates. Therefore, rates of use of these different supports by claw-bearing arboreal mammals may offer insights to their actual significance in the adaptive evolution of early primates. In this context, canopy, tree crown, branch size, inclination, and texture use were recorded on four adult free ranging European red squirrelsSciurus vulgaris Linnaeus, 1758 in a mixed coniferous forest in northern Greece.S. vulgaris was mainly arboreal, exploiting the terminal branch zone, using frequently oblique and intermediately textured supports<5 cm and moderately large vertical branches. Furthermore, comparative data from other sciurid species and clawed primates showed positive correlations of small and horizontal support use, and negative ones of vertical support use to body mass. These findings show that keeled functional claws do not impede habitual use of slender branches and may not facilitate efficient climbing on large vertical trunks. These observations partly question the association between habitual use of the small branch niche and primate adaptations and lend support to alternative hypotheses, underscoring the importance of inquiring for more complex mechanisms that lead to the evolution of the unique set of primate morphological adaptations.
The feeding habits and hoarding behaviour of the Eurasian red squirrel Sciurus vulgaris Linnaeus, 1758 were examined during autumn in Nopporo Forest Park (43°20'N, 141°30'E), in western Hokkaido, Japan. The diet consisted of 32 plant species. Twelve species were both eaten and hoarded (the two most common of which were Abies sachalinensis and Pinus koraiensis), and 20 species were eaten but not hoarded. The distance from where a food item was found to the hoarding spot averaged 50 m and differed significantly according to food type. Walnuts Juglans regia were transported farthest, and chestnuts Castanea crenata to the second farthest from the site of origin. Most food was hoarded beneath the ground surface (95%), but some were hoarded in forks of trees and in small tree holes. Squirrels selected food items of high energy content for hoarding, in preparation for winter and the breeding season.
A survey of Babesia, Theileria and Hepatozoon was conducted in wild mammals, including the capybara (Hydrochaeris hydrochaeris; n = 14) from Brazil, the jaguar (Panthera onca; n = 2) and crab-eating raccoon (Procyon cancrivorus; n = 4) from Venezuela, and the red deer (Cervus elaphus; n = 70), red squirrel (Sciurus vulgaris; n = 5) and Eurasian pine marten (Martes martes; n = 3) from Spain. Diagnostic procedures included both microscopy and molecular methods (PCR and sequencing of the 18S rRNA gene). Microscopic examination of blood smears revealed no hematozoan infections — unlike the molecular analyses. Nine Brazilian capybaras were found to be infected with Hepatozoon canis (prevalence 64%), two of which were coinfected with a previously unknown babesid (prevalence 14%) loosely related to Theileria equi (90% 18S rRNA gene similarity according to BLAS® analysis). One jaguar and one crab-eating raccoon from Venezuela were infected by H. canis. Four of the red deer were infected with theilerids (5.7% prevalence), two with Theileria sp. and two with T. annulata. One red squirrel and three pine martens were infected with Hepatozoon sp. The isolate form the red squirrel was phylogenetically related to Hepatozoon sp. reported in Spanish bank voles, whereas those infecting the pine martens were related to Hepatozoon felis reported in Spanish cats. In conclusion, the molecular findings show that some non-canid mammals are carriers of H. canis in South America, while red deer may carry T. annulata in Europe. Small mammals in Europe appear to be unlikely hosts of H. canis and H. felis.
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