Audiogram of the harp seal in air (Pagophilus groenlandicus)
Data from: Terhune, J.M., and Ronald, K. (1971) The harp seal Pagophilus groenlandicus (Erxleben 1777). The air audiogram. Journal of Canadian Zoology, 49, 385-390.
Absolute thresholds (in dB re 2 µN/m2) for a harp seal in air
|
Frequency (in kHz) |
Average Threshold (in dB) |
|
|
1 |
33 |
|
|
1.4 |
39 |
|
|
2 |
33 |
|
|
2.8 |
37 |
|
|
4 |
29 |
|
|
5.6 |
34 |
|
|
8 |
38 |
|
|
11.3 |
35 |
|
|
16 |
41 |
|
|
22.9 |
41 |
|
|
32 |
42 |
|
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 |
— |
— |
|
60 |
— |
— |
|
50 |
— |
— |
|
40 |
— |
15 |
|
30 |
— |
— |
Additional Parameters:
Body weight = 180 kg
Functional interaural distance = ???? µs
(Time required for sound to travel around the head from one auditory meatus to the other.)
Comments: Threshold values taken from Terhune and Ronald, 1971.
Audiogram of the harp seal in water (Pagophilus groenlandicus)
Data from: Terhune, J.M., and Ronald, K. (1972) The harp seal Pagophilus groenlandicus (Erxleben 1777). III. The underwater audiogram. Journal of Canadian Zoology, 50, 565-569.
Absolute thresholds (in dB re 2 µN/m2) for a harp seal in water
|
Frequency (in kHz) |
Average Threshold (in dB) |
|
|
.760 |
15 |
|
|
1 |
16 |
|
|
1.4 |
7 |
|
|
2 |
7 |
|
|
2.8 |
6 |
|
|
4 |
13 |
|
|
5.6 |
12 |
|
|
8 |
7 |
|
|
11.3 |
7 |
|
|
16 |
9 |
|
|
22.9 |
5 |
|
|
32 |
12 |
|
|
44.9 |
14 |
|
|
55 |
19 |
|
|
64 |
41 |
|
|
90 |
52 |
|
|
100 |
94 |
|
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 |
— |
94 |
|
60 |
— |
91 |
|
50 |
— |
85 |
|
40 |
— |
63 |
|
30 |
— |
59 |
Additional Parameters:
Body weight = 180 kg
Functional interaural distance = 120 µs
(Time required for sound to travel around the head from one auditory meatus to the other.)
Comments: Threshold values taken from Terhune and Ronald, 1972.
For a good discussion of air and water hearing, see 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.
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