Geographic variations in underwater male Weddell seal Trills suggest breeding area fidelity

John M. Terhune, Douglas Quin, Andrea Dell'Apa, Mandana Mirhaj, Joachim Plötz, Lars Kindermann, Horst Bornemann

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


Adult Weddell seals (Leptonychotes weddellii) exhibit site fidelity to where they first breed but juveniles, and perhaps transient adult males, may disperse from their natal location. If there is mixing between adjacent breeding groups, we would expect that common vocalizations would exhibit clinal patterns. Underwater Trill vocalizations of male Weddell seals at Mawson, Davis, Casey, McMurdo Sound, Neumayer and Drescher Inlet separated by ca. 500 to >9,000 km, were examined for evidence of clinal variation. Trills are only emitted by males and have a known territorial defense function. Trills from Davis and Mawson, ca. 630 km apart, were distinct from each other and exhibited the greatest number of unique frequency contour patterns. The acoustic features (duration, waveform, frequency contour) of Trills from Neumayer and Drescher Inlet, ca. 500 km apart, were more distinct from each other than they were from the other four locations. General Discriminant Analysis and Classification Tree Analysis correctly classified 65.8 and 76.9% of the Trills to the correct location. The classification errors assigned more locations to sites >630 km away than to nearest neighbours. Weddell seal Trills exhibit geographic variation but there is no evidence of a clinal pattern. This suggests that males remain close to single breeding areas throughout their lifetime.

Original languageEnglish (US)
Pages (from-to)671-680
Number of pages10
JournalPolar Biology
Issue number6
StatePublished - May 2008
Externally publishedYes


  • Geographic variation
  • Leptonychotes weddellii
  • Reproduction
  • Site fidelity
  • Underwater vocalizations
  • Weddell seal

ASJC Scopus subject areas

  • General Agricultural and Biological Sciences


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