title: Flow sensing by pinniped whiskers.
abstract: Beside their haptic function, vibrissae of harbour seals (Phocidae) and California sea lions (Otariidae) both represent highly sensitive hydrodynamic receptor systems, although their vibrissal hair shafts differ considerably in structure. To quantify the sensory performance of both hair types, isolated single whiskers were used to measure vortex shedding frequencies produced in the wake of a cylinder immersed in a rotational flow tank. These measurements revealed that both whisker types were able to detect the vortex shedding frequency but differed considerably with respect to the signal-to-noise ratio (SNR). While the signal detected by sea lion whiskers was substantially corrupted by noise, harbour seal whiskers showed a higher SNR with largely reduced noise. However, further analysis revealed that in sea lion whiskers, each noise signal contained a dominant frequency suggested to function as a characteristic carrier signal. While in harbour seal whiskers the unique surface structure explains its high sensitivity, this more or less steady fundamental frequency might represent the mechanism underlying hydrodynamic reception in the fast swimming sea lion by being modulated in response to hydrodynamic stimuli impinging on the hair.
authors.affiliation: Biosciences, Sensory and Cognitive Ecology, University of Rostock, Albert-Einstein-Strasse 3, 18059 Rostock, Germany.
authors.forename: L
authors.initials: L
authors.lastname: Miersch
authors.forename: W
authors.initials: W
authors.lastname: Hanke
authors.forename: S
authors.initials: S
authors.lastname: Wieskotten
authors.forename: F D
authors.initials: FD
authors.lastname: Hanke
authors.forename: J
authors.initials: J
authors.lastname: Oeffner
authors.forename: A
authors.initials: A
authors.lastname: Leder
authors.forename: M
authors.initials: M
authors.lastname: Brede
authors.forename: M
authors.initials: M
authors.lastname: Witte
authors.forename: G
authors.initials: G
authors.lastname: Dehnhardt
mesh_terms: D000818:Animals; D010872:Caniformia / Q000033:anatomy & histology / Q000502:physiology*; D057446:Hydrodynamics; D059629:Signal-To-Noise Ratio; D014110:Touch / Q000502:physiology*; D014738:Vibrissae / Q000033:anatomy & histology / Q000502:physiology*