Arboreal locomotor and postural behaviour of European red squirrels (Sciurus vulgaris L.) in northern Greece

Abstract

The study of the locomotion and postures of arboreal squirrels may provide important contextual information on the evolution of the morphology and ecology of sciurids. In this context, we studied the positional behaviour and habitat use of four adult European red squirrels (Sciurus vulgaris L.) in a mixed coniferous forest in northern Greece. Our results show that, during the study period, S. vulgaris extensively used the forest canopy and the terminal branch zone. The use of small and medium supports of all orientations was also particularly frequent. The positional profile of the species was characterized by the dominance of quadrupedal, clawed and airborne locomotion along with seated and standing postures. Quadrupedalism and sitting appeared to promote terminal branch use for food access and manipulation, while claw climbing favored vertical ranging and retreat to trees after terrestrial foraging. Finally, leaping reduced energetic costs during travelling between food sites within the relatively dispersed forest. These results and those of previous research on the positional behaviour of other squirrels reveal several trends related to body size, arboreal or gliding habits and tropical or temperate forest distribution and contribute to the understanding of evolutionary novelty in multiple levels within the sciurid radiation.

Angular momentum and arboreal stability in common marmosets (Callithrixjacchus)

“…In summary, the use of asymmetrical gaits allowed marmosets to create functional grasping appendages, facilitating the production of muscular torques about the substrate despite their relatively poor development of typical primate grasping morphology. This hypothesized relationship between asymmetrical gaits and the creation of functional grasping appendages may explain the frequent use of asymmetrical gaits in other small‐bodied arboreal mammals, including didelphid marsupials (Pridmore, ), tree squirrels (Youlatos and Samaras, ), tree shrews (Jenkins, ), mouse lemurs (Shapiro et al, ), and other callitrichids (Fleagle and Mittermeier, ; Garber, ; Rosenberger and Stafford, ; Nyakatura and Heymann, ). As noted above, high speed asymmetrical gaits also confer dynamic stability, further mitigating arboreal balance disruptions (Bruijn et al, ).…”

Total recoil: perch compliance alters jumping performance and kinematics in green anole lizards (Anolis carolinensis)

“…Recent work has shown the value of examining locomotion in nature, and how animals interact with habitat structure (Fulton et al, 2001;Irschick and Losos, 1999;Johansen et al, 2007;Mattingly and Jayne, 2004;Youlatos and Samaras, 2011). Green anoles in the wild segregate perches across age or sex classes based on perch diameter: smaller animals use narrow perches, and larger animals use larger perches (Irschick et al, 2005a).…”

Pedal grasping in an arboreal rodent relates to above‐branch behavior on slender substrates

“…Only the larger species (e.g. Sciurus granatensis , S. igniventris , S. carolinensis , S. vulgaris ) seem to exert some prehensile grasping and adequately use the slender twigs of tree peripheries (Garber & Sussman, ; Youlatos, ; Orkin & Pontzer, ; Youlatos & Samaras, ). Otherwise, they basically depend on their functional claws to negotiate most arboreal substrates.…”

“…This occurs because subsequent samples of the same individuals usually lack independence from previous observations (Dawkins, ). In order to address this shortcoming and safely guarantee independence, we followed a bout trimming procedure (see Youlatos & Samaras, ). Initially, the complete dataset was divided into locomotor and postural subsets.…”