Bioacoustics of Galidia

Movements, Home range and Social organization. Roland Albignac conducted fieldwork on this species in several different forest types and consistently estimated home range size, extrapolated from trapping studies, to be 20 to 25 ha. On the basis of a short-term capture-mark-release study in humid forest in the Ranomafana National Park, the density index was estimated to be 37 animals per km? which may be a slight overestimation. An animal marked in the humid forest in the extreme south-east at 810 m elevation was observed several days later at 1200 m , a straight-line distance of about 2-5 km. In some zones it can reach noticeably high densities. For example, at 1000 m on Montagne d’Ambre, it was very common in the mid-1990s. During the course of seven days of trapping at this locality, with 20 carnivore traps set each day, more than 28 Ring-tailed Vontsira were captured in a relatively limited area. This forested site has high densities of introduced Rattus, which the Ring-tailed Vontsira feed upon. Little is published about the social organization of this species in the wild, but based on field studies it appearsto live, at least seasonally, solitarily or in small groups of three to four individuals. The small groups presumably are composed of a male-female pair and their sub-adult young. Aggressive encounters between individuals, particularly adult males, often include a distinctive submissive display by the non-dominant animal. The submissive animal bends the front limbs so the chest practically touches the ground, the ears are folded backwards, the teeth exposed, and the snout is pointed up, almost touching the face of the dominant animal. When the dominant individual approaches, the submissive animal gives a loud, high-pitched screeching vocalization. Trapped animals produce a two-part threat call, a guttural growl followed by a raspy spitting sound. This species is rather vocal and its auditory signals have been classified into four types : a whistle-like contact call between family members, often given while moving through the forest; a specific prey capture call; growl and shrill screams as intimidation, attack or defense calls; and a copulation vocalization. Adults regularly scent-mark within their home range using urine and a form of musk produced by their perineal, cheek, and sub-mandibular glands. Dens of this species have been found in a variety of settings, and it is capable of digging its own burrow systems. In exposed sedimentary rock zones, such as the Bemaraha Plateau, lairs have been found in rock crevices and subterranean passages. In the humid forests of the east, dens tend to be in the ground underlarge trees, in carved-outsoil fissures along riverbanks, or in the hollow bases of large standing trees or downed hollow logs. Often the dens have numerous openings. They are not necessarily used by the same individuals on consecutive nights.