70
D.R. Ketten
160
10
40
Cw
r =-0.92
G"
80
160
320
640
1280
Interaural Time Difference (lIseC)
2560
E '.
r = -0.84
FIGURE 2.5. Interaural time differences versus high-frequency hearing limit. Highfrequency functional hearing limits (sensu Fay 1992) are plotted against interaural
time distances for aquatic and land mammals. For in-air limits, the frequency at
60dB re 20J..lPa was used; for animals in water, the frequency corresponding to 120
dB re 1 J..lPa. External intermeatal distances were used to calculate interaural time
distances (IATD) for land mammals and otarrids tested in air. Intercochlear distances (which are isomorphic with intermandibular distances in odontocetes) were
used for cetaceans and underwater pinniped IATD calculations. A separate regression was calculated based on underwater audiometric data alone. Data were compiled from Watkins and Wartzok (1985); Payne, Langbauer, and Thomas (1986); Fay
(1988); Heffner and Masterson (1990); Ketten (1992; unpublished data); Heffner and
Heffner (1992; personal communication); Richardson et al. (1995). Marine mammals
are coded numerically; land mammals, by initial of English name.
Marine mammals: 1. harbour porpoise, Phocoena phocoena; 2. bottlenose dolphin,
Tursiops truncatus; 3. bouto, Inia geoffrensis; 4. sea otter, Enhydra lutris; 5. Atlantic
whitesided dolphin, Lagenorhynchus acutus; 6. Risso's dolphin (Grampus),
Grampus griseus; 7. beluga, Delphinapterus leucas; 8. false killer whale, Pseudorca
crassidens; 9. manatee, Trichechus manatus; 10. harbour seal, Phoca vitulina; 11. harp
seal, Phoca groenlandicus; 12. sea lion, Zalophus califomicus; 13. sperm whale,
Physeter catadon; 14. humpback whale, Megaptera novaeangliae; 15. blue whale,
Balaenoptera musculus.
Land mammals: C. Cat, Felis domesticus Ch. chinchilla, Chinchilla langer; Cpo
chimpanzee, Pan paniscus; Cwo cow, Bos taurus; D. dog, Canis familiaris; E. elephant,
Elephas maxlmus; G.** Gopher Geomys bursarius; Gp. guinea pig, Cavia procellus;
Hg. hedgehog, Paraechinus hypomelas; B. bat, Rhinolophus ferrumequinum; H.
human, Homo sapiens; K. kangaroo rat, Dipodomys merriami; Mq. macaque,
Macacca mulatta; S** mole rat, Spalax ehrenbergl; M. mouse, Mus musculus; Rb.
rabbit, Oryctolagus cuniculus; R. rat, Rattus norvegicus albino; S. sheep, Ovis aries;
My. squirrel monkey, Saimiri sciureus.
*Functional hearing limits estimated from cochlear model data (Ketten 1992,1994,
unpublished data).
** Data points not included in regression calculations.-in-air measures for marine
species.
D.R. Ketten
160
10
40
Cw
r =-0.92
G"
80
160
320
640
1280
Interaural Time Difference (lIseC)
2560
E '.
r = -0.84
FIGURE 2.5. Interaural time differences versus high-frequency hearing limit. Highfrequency functional hearing limits (sensu Fay 1992) are plotted against interaural
time distances for aquatic and land mammals. For in-air limits, the frequency at
60dB re 20J..lPa was used; for animals in water, the frequency corresponding to 120
dB re 1 J..lPa. External intermeatal distances were used to calculate interaural time
distances (IATD) for land mammals and otarrids tested in air. Intercochlear distances (which are isomorphic with intermandibular distances in odontocetes) were
used for cetaceans and underwater pinniped IATD calculations. A separate regression was calculated based on underwater audiometric data alone. Data were compiled from Watkins and Wartzok (1985); Payne, Langbauer, and Thomas (1986); Fay
(1988); Heffner and Masterson (1990); Ketten (1992; unpublished data); Heffner and
Heffner (1992; personal communication); Richardson et al. (1995). Marine mammals
are coded numerically; land mammals, by initial of English name.
Marine mammals: 1. harbour porpoise, Phocoena phocoena; 2. bottlenose dolphin,
Tursiops truncatus; 3. bouto, Inia geoffrensis; 4. sea otter, Enhydra lutris; 5. Atlantic
whitesided dolphin, Lagenorhynchus acutus; 6. Risso's dolphin (Grampus),
Grampus griseus; 7. beluga, Delphinapterus leucas; 8. false killer whale, Pseudorca
crassidens; 9. manatee, Trichechus manatus; 10. harbour seal, Phoca vitulina; 11. harp
seal, Phoca groenlandicus; 12. sea lion, Zalophus califomicus; 13. sperm whale,
Physeter catadon; 14. humpback whale, Megaptera novaeangliae; 15. blue whale,
Balaenoptera musculus.
Land mammals: C. Cat, Felis domesticus Ch. chinchilla, Chinchilla langer; Cpo
chimpanzee, Pan paniscus; Cwo cow, Bos taurus; D. dog, Canis familiaris; E. elephant,
Elephas maxlmus; G.** Gopher Geomys bursarius; Gp. guinea pig, Cavia procellus;
Hg. hedgehog, Paraechinus hypomelas; B. bat, Rhinolophus ferrumequinum; H.
human, Homo sapiens; K. kangaroo rat, Dipodomys merriami; Mq. macaque,
Macacca mulatta; S** mole rat, Spalax ehrenbergl; M. mouse, Mus musculus; Rb.
rabbit, Oryctolagus cuniculus; R. rat, Rattus norvegicus albino; S. sheep, Ovis aries;
My. squirrel monkey, Saimiri sciureus.
*Functional hearing limits estimated from cochlear model data (Ketten 1992,1994,
unpublished data).
** Data points not included in regression calculations.-in-air measures for marine
species.