UNDERWATER AUDIOGRAM OF THE CALIFORNIA SEA LION BY THE CONDITIONED VOCALIZATION TECHNIQUE¹

Abstract

Conditioning techniques were developed demonstrating that pure tone frequencies under water can exert nearly perfect control over the underwater click vocalizations of the California sea lion (Zalophus californianus). Conditioned vocalizations proved to be a reliable way of obtaining underwater sound detection thresholds in Zalophus at 13 different frequencies, covering a frequency range of 250 to 64,000 Hz. The audiogram generated by these threshold measurements suggests that under water, the range of maximal sensitivity for Zalophus lies between one and 28 kHz with best sensitivity at 16 kHz. Between 28 and 36 kHz there is a loss in sensitivity of 60 dB/octave. However, with relatively intense acoustic signals (> 38 dB re 1 mub underwater), Zalophus will respond to frequencies at least as high as 192 kHz. These results are compared with the underwater hearing of other marine mammals.

Pinniped Hearing in Complex Acoustic Environments

“…The close correspondence between the two individuals with presumably normal hearing tested in our laboratory are consistent with a revised analysis (Reichmuth and Southall, 2010) of earlier data obtained with this species (Schusterman et al, 1972), and can be considered the most representative species-typical hearing data currently available for otariid pinnipeds (sea lions and fur seals).…”

Formação de classes funcionais de estímulos musicais

“…Esta função reúne a maior parte dos estudos usando estímulos sonoros na Análise do Comportamento (Beecher & Harrison, 1971;Burlile, Feldman, Craig, & Harrison, 1985;Crites, Harris, Rosenquist, & Thomas, 1967;Downey & Harrison, 1972Farris, 1967;Green, 1975;Harrison & Briggs, 1977;Harrison, Iversen, & Pratt, 1977;Harrison, 1988;Herman & Gordon, 1974;Lewis & Stoyak, 1979;Neill & Harrison, 1987;Neill, Liu, Mikati, & Holmes, 2005;Raslear, 1975;Raslear, Pierrel-Sorrentino, & Brissey, 1975;Reed, Howell, Sackin, Pizzimenti, & Rosen, 2003;Schusterman, Balliet, & Nixon, 1972;Segal & Harrison, 1978;Stebbins, 1966). Em geral, esses estudos assemelham-se: frequentemente utilizaram ratos como sujeitos e sons simples como estímulos (descritos pela frequência em Hertz).…”

Morphometric analysis of ears in two families of pinnipeds

“…Thirty years ago, the publication of the first seal behavioral audiogram (Møhl 1968a) changed the emphasis from anatomy to behavior for studying these systems. Additional audio grams followed representing both aerial and underwater thresholds of numerous seal and sea lion species including the harp seal, Phoca groenlandicus, (Terhune andRonald 1971,1972), the ringed seal, Phoca hispida, (Ronald and Terhune 1975), the California sea lion, Zalophus californianus, (Schusterman et al 1972;Schusterman 1974), the northern fur seal, Callorhinus ursinus, (Moore and Schusterman 1987), the Hawaiian monk seal, Monachus schauinslandi, (Thomas et al 1990), the Pacific walrus, Odobenus rosmarus, (Kastelein et al 1996), and the northern elephant seal, Mirounga angustirostris, (Kastak and Schusterman 1997). Recent papers (Kastak and Schusterman 1998;) have used behavioral techniques to show significant hearing differences between largely aquatic seals (phocids) and largely terrestrial sea lions (otariids).…”

“…There is a relatively large body of behavioral work on their hearing abilties (Møhl 1968a(Møhl , 1968bSchusterman et al 1972;Schusterman 1974;Moore and Schusterman 1987;Schusterman 1998, 1999;Southall et al 2000). In addition, specimens for dissection are not generally difficult to obtain.…”

“…-iCalíforna sea lion (Schusterman 1974) 20 J I _Northern elephant seal Schusterman 1998,1999) (Møhl 1968a) --Calorna sea lion (Schusterman et aL. 1972) _Northern elephant seal Schusterman 1998,1999) 100 1000 10000 100000 1000000 Frequency (Hz) Figure 6, Píniped underwater audiograms.…”