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Audiogram of the common harbor seal in air (Phoca vitulina)

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Data from:

Mohl, B. (1968) Auditory sensitivity of the common seal in air and water. Journal of Auditory Research, 8, 27-38.one animal

Kastak, D., and Schusterman, R.J. (1998) Low-frequency amphibious hearing in pinnipeds: Methods, measurements, noise, and ecology. Journal of the Acoustical Society of America, 103,2216-2228. one animal

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Absolute thresholds (in dB re 2 µN/m²) for three common harbor seals in air (A through C as indicated above)

Ìý Frequency (in kHz)	Individual Thresholds (in dB)				Ìý Average
	Mohl	Kastak & Schusterman	Ìý	Ìý
.100	—	65.4	Ìý	65.4
.200	—	57.2	Ìý	57.2
.400	—	52.9	Ìý	52.9
.800	—	26.1	Ìý	26.1
1	36	—	Ìý	36
1.42	34	—	Ìý	34
1.6	—	42.8	Ìý	42.8
2	19	—	Ìý	19
2.8	22	—	Ìý	22
3.2	—	30.2	Ìý	30.2
4	26	—	Ìý	26
6.4	—	19.2	Ìý	19.2
8	19	—	Ìý	19
11.25	16	—	Ìý	16
16	26	—	Ìý	26
22.5	58	—	Ìý	58
Ìý	Ìý	Ìý	Ìý	Ìý	Ìý	Ìý

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Lowest and highest frequencies audible at sound

pressure levels (SPL) ranging from 30 to 70 dB SPL

SPL (in dB)	Lowest audible frequency (in kHz)	Highest audible frequency (in kHz)
70	.070*	—
60	.160	23
50	.460	20.5
40	.560	18.5
30	.720	16.9

*extrapolated value

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Additional Parameters:

Body weight = 40 kg

Functional interaural distance= 378 µs

(Time required for sound to travel around the head from one auditory meatus to the other.)

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Comments: Threshold values taken from Mohl, 1968, Kastak and Schusterman, 1998,

For additional thresholds for one individual, see Turnbull, S.D., and Terhune, J.M. (1990) White noise and pure tone masking of pure tone thresholds of a harbor seal listening in air and underwater. Canadian Journal of Zoology, 68, 2090-2097.

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Audiogram of the common harbor seal in water (Phoca vitulina)

Ìý Frequency (in kHz)	Individual Thresholds (in dB)				Ìý Average
	Mohl	Kastak & Schusterman	Ìý	Ìý
.075	—	40.3	Ìý	40.3
.100	—	34.3	Ìý	34.3
.200	—	22.2	Ìý	22.2
.400	—	22.3	Ìý	22.3
.800	—	18.2	Ìý	18.2
1	20	—	Ìý	20
1.6	—	5.5	Ìý	5.5
2	11	—	Ìý	11
4	4	—	Ìý	4
6.4	—	1.2	Ìý	1.2
8	3	—	Ìý	3
16	0	—	Ìý	0
32	-1	—	Ìý	-1
45	8	—	Ìý	8
64	42	—	Ìý	42
90	56	—	Ìý	56
128	61	—	Ìý	61
180	69	—	Ìý	69
Ìý	Ìý	Ìý	Ìý	Ìý	Ìý	Ìý

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Lowest and highest frequencies audible at sound

pressure levels (SPL) ranging from 30 to 70 dB SPL

SPL (in dB)	Lowest audible frequency (in kHz)	Highest audible frequency (in kHz)
70	—	180
60	—	120
50	—	78
40	.075	62
30	.125	57

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Additional Parameters:

Body weight = 40 kg

Functional interaural distance= 80 µs

(Time required for sound to travel around the head from one auditory meatus to the other in water.)

Ìý

Comments: Threshold values taken from Mohl, 1968, Kastak and Schusterman, 1998. Values converted from a reference level of 1 microPascal. For additional thresholds for one individual, see Turnbull, S.D., and Terhune, J.M. (1990) White noise and pure tone masking of pure tone thresholds of a harbor seal listening in air and underwater. Canadian Journal of Zoology, 68, 2090-2097.

Ìý

For a good discussion of air and water hearing, see Kastak, D., and Schusterman, R.J. (1998) Low-frequencyamphibious hearing in pinnipeds: Methods, measurements, noise, and ecology. Journal of the Acoustical Society of America, 103,2216-2