Evaluating the function of the male harbour seal, Phoca vitulina , roar through playback experiments

Geographic variation and acoustic structure of the underwater vocalization of harbor seal (Phoca vitulina) in Norway, Sweden and Scotland

“…6͒. These sound types have, to our knowledge, not been documented in other harbor seal colonies that have been fairly well studied ͑Hanggi and Schusterman 1994; Van Parijs et al, 1999, 2000a, 2003Hayes et al, 2004͒. Tonal introductory phrases were characteristic for seals from Sandøy in Møre, Kongsfjord in Finnmark and Eynhallow at the Orkney Islands ͑Table II͒.…”

“…During the mating season, from July to late August, male harbor seals restrict their home range and start spending much of their time in the water at particular sites where they perform short stereotypic dives described as display activity ͑Bjørge, 1995; Van Parijs et al, 1997, 2000a, 2000bHayes et al, 2004͒. Favorable display sites are generally located in areas where female encounter rate is particular high ͑e.g., close to female haul-out and pupping sites͒, but males have been shown to display also over a wider area covering the whole of the female distribution ͑Van Parijs et al, 1997Parijs et al, , 1999.…”

“…The short, stereotypic dives may be repeated for periods up to 7 hours and males appear to show strong site fidelity towards display sites ͑Bjørge et Van Parijs et al, 2000b͒. During each dive, the male emits between one and five loud vocalizations ͑Hanggi and Schusterman, 1994; Bjørge et al, 1995;Van Parijs et al, 1997, 2000aHayes et al, 2004;see Fig. 1͒.…”

“…The roar is the only harbor seal vocalization that is reported from all studied areas, i.e., USA ͑Hanggi and Schusterman, 1994; Hayes et al, 2004͒, Norway ͑Bjørge et al, 1995͒, Sweden ͑Wahlberg et al, 2002͒, Scotland, U.K. ͑Van Parijs et al, 1997, 2000a͒, and Canada ͑Van Parijs et al, 20022003͒. The function of the roar vocalization appears primarily to be advertising the presence of a male in breeding condition, and has therefore been suggested to be used in male-male competition and/or as reproductive advertisement display to attract females ͑Hanggi and Schusterman, 1994;Van Parijs et al, 1997, 2000a, 2000bHayes et al, 2004͒. Similar sexual display behavior is observed in other male pinnipeds such as walruses ͑Odo-benus rosmarus͒ ͑Ray and Watkins, 1975;Stirling et al, 1983, bearded seals ͑Erignathus barbatus͒ ͑Ray et al, 1969;Cleator et al, 1989͒, and Weddell seals ͑Leptonycho-tes weddelli͒ ͑Thomas and Kuechle, 1982; Thomas and Stirling, 1983͒ seals. Recent research has shown that vocal variation in harbor seal roars occurs at the oceanic, regional, population, and subpopulation level ͑Van Parijs et al, 1999, as well as individual variation in temporal ͑Van Parijs et al, 2000a͒ andspectral features ͑Hanggi andSchusterman, 1994;Van Parijs et al, 2000a͒.…”

Source levels and call parameters of harbor seal breeding vocalizations near a terrestrial haulout site in Glacier Bay National Park and Preserve

“…During the breeding season, male harbor seals establish underwater territories and use breeding vocalizations, known as roars, to defend these areas against other males and possibly to attract females (Hanggi and Schusterman, 1994;Hayes et al, 2004b). Previous studies indicate that Pacific harbor seals in California (Phoca vitulina richardii) produce roars that are 2-10 s long and occupy the 300-1100 Hz band (Hanggi and Schusterman, 1994).…”