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, juveniles, and females without young, referred to as "singles") were investigated. 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 consisted of several breathing holes and lairs; the maximum distance between the 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 ranges of 11 seals did not overlap. In one instance, the home ranges of a female and a single overlapped. The average distance between home ranges of neighbouring seals found within one ice-ridge was 750 m and between home ranges within different ice-ridges was 1,340 m. The space between home ranges might 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 female uses the adjacent areas. In comparison, single seal's diving activity does not concentrate in this way with respect to widely spaced breathing holes. Since Baikal seals avoid one another while hauling out prior to moulting, vocal communication probably plays an important role in avoidance underwater and also in subsequent mate finding.