title: Underwater sound localization of pure tones in the median plane by harbor seals (Phoca vitulina).
abstract: In an underwater environment the physical characteristics of sound propagation differ considerably from those in air. For this reason, sound localization underwater is associated with difficulties, especially in the median plane. It was the approach of the present study to investigate whether harbor seals (Phoca vitulina) are able to determine the direction of a tonal signal form above or below in the underwater environment. Minimum audible angles (MAAs) or the angular range in which the animals could localize a pure tone stimulus in the vertical plane were obtained for frequencies from 0.35 up to 16 kHz. Testing was conducted with four male harbor seals in a semi-circle area of 6 m in diameter in about 2.5 m depth, by using a two alternative forced choice method. The results show that harbor seals are able to localize a pure tone in the median plane under water with a high performance for low frequency stimuli between 350 Hz and 2 kHz with MAAs ranging from below 2.5° up to about 25°. For higher frequencies the animals show strong individual differences.
authors.affiliation: Sensory and Cognitive Ecology, University of Rostock, Albert-Einstein Strasse 3, 18059 Rostock, Germany.
authors.forename: Jenny Ann
authors.initials: JA
authors.lastname: Byl
authors.affiliation: Sensory and Cognitive Ecology, University of Rostock, Albert-Einstein Strasse 3, 18059 Rostock, Germany.
authors.forename: Lars
authors.initials: L
authors.lastname: Miersch
authors.affiliation: Sensory and Cognitive Ecology, University of Rostock, Albert-Einstein Strasse 3, 18059 Rostock, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Wieskotten
authors.affiliation: Sensory and Cognitive Ecology, University of Rostock, Albert-Einstein Strasse 3, 18059 Rostock, Germany.
authors.forename: Guido
authors.initials: G
authors.lastname: Dehnhardt
mesh_terms: D000818:Animals; D008297:Male; D046049:Phoca; D013016:Sound; D013017:Sound Localization; D013018:Sound Spectrography; D014867:Water
chemical_list: D014867:Water