Comparison of frequency of occurrence of broadcast calls (H, M, D, L, O) and variant calls (HV, MV, DV, LV) occurring in randomly chosen leopard seal vocalizations; 450 from adult seals and 450 from subadult seals.
Sonagrams of a leopard seal high double trill (H) and examples of the seven types of variants of this call (HV).
Sonagrams of a leopard seal medium single trill (M) and examples of the five types of variants of this call (MV).
Sonagrams of a leopard seal low double trill (L) and hoot with a single trill (O) and examples of the eight types of variants of these low frequency calls (LVs).
Leopard seal call repertoires recorded form different Antarctic areas; South Shetland Islands (SS) (Stirling and Siniff, 1979), Palmer Peninsula (PP), McMurdo Sound (MS) (Thomas and Golladay, 1995) and Prydz Bay (PB) (Rogers et al., 1995). Westward drift of the ice is the ice movement parallel to the bathymetry that hugs near the Antarctic continent where the eastward drift of the ice is further out from the Antarctic continent. Call double trill and double trill (), call single trill and descending trill (●), Call double trill (▴), Calls 6, 7, 8, 9, (★), and Call with a single low trill (∎).
Criteria used to distinguish whether a subadult’s call was a broadcast call or a variant type call.
Number of broadcast calls analyzed per seal: high double trills (H), medium single trills (M), low descending trills (D), low double trills (L), and hoots with a single trill (O); and the number of vocalizing bouts and periods analysed per seal.
ANOVA comparison between acoustic characteristics measured from the five adult and five sub-adult male leopard seal calls, data from variant calls are not included.a
ANOVA comparison between duration and number of units in vocalizing and inter-vocalizing periods produced by adult and sub-adult male leopard seals (an asterisk denotes significant at 0.05 level).
ANOVA comparison between calling rates in recordings from adult and sub-adult male leopard seals (an asterisk denotes significant at 0.05 level).
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