Surface home ranges of the Baikal seal (Phoca sibirica) during the solid ice-cover period

Home ranges of six nursing females and seven single Baikal seals (males, ju veniles, and females without young, referred to as "singles") were investig ated. Female lair systems consisted of a main lair and 0-2 accessory holes at a maximum of 40 m from the main lair. The single seals' home ranges cons isted of several breathing holes and lairs; the maximum distance between th e most recently used breathing holes of individual seals was an average of 920 m, with a minimum polygon range area of 0.26 km(2). The surface home ra nges of 11 seals did not overlap. In one instance, the home ranges of a fem ale and a single overlapped. The average distance between home ranges of ne ighbouring seals found within one ice-ridge was 750 m and between home rang es within different ice-ridges was 1,340 m. The space between home ranges m ight be used mutually, especially in the case of female seals. In lactating females, the lair system serves as a centre of the home range and the fema le uses the adjacent areas. In comparison, single seal's diving activity do es not concentrate in this way with respect to widely spaced breathing hole s. Since Baikal seals avoid one another while hauling out prior to moulting , vocal communication probably plays an important role in avoidance underwa ter and also in subsequent mate finding.