Stability in acoustic behavior has been shown on similar time scales in harp seals (Serrano and Terhune, 2002) and bearded seals (Van Parijs and Clark, 2006), suggesting that it may be common among ice-breeding phocids. Ringed and ribbon seals lack geographic variation where compared in this study.
Key words: ringed seal, bearded seal, ribbon seal, Arctic phocid, call repertoire, seasonality, vocalization, sea ice
Ringed seals (Pusa hispida), bearded seals (Erignathus barbatus), and ribbon seals (Histriophoca fasciata) are ice-breeding phocid species with ranges that overlap across a large area of the Bering, Chukchi, and Beaufort Seas.
Ringed seals are the most numerous and widely distributed of the Arctic phocid species (Kelly et al., 2010).
The size of the vocal repertoire has been related to the mating system in phocid seals.
Other Arctic and subarctic phocid species that have shown increases in vocal activity during their breeding seasons include hooded seals (Cystophora cristata) (Ballard and Kovacs, 1995), harbor seals (Phoca vitulina) (Van Parijs et al., 1999), and bearded seals (Van Parijs et al., 2001).
This result is consistent with studies of other phocid seals and raises additional questions about the function of their vocalizations.
Together, these areas comprise a substantial portion of the distribution of Arctic phocid species that rely on the Marginal Ice Zone and drifting pack ice for key aspects of their life histories.
Although adult SSLs are larger than many species of phocid seals, phocids have much shorter lactation periods and their pups grow at a more accelerated rate than do otariids.
In phocids, most studies have found no difference in neonatal male and female growth rates, regardless of whether the data were longitudinal or cross sectional (Stewart and Lavigne, 1980; Innes et al., 1981; Bowen et al., 1992).
Maternal investment and neonatal growth in phocid seals.