Gray Whale Sounds (Eschrichtius robustus)
Gray whales are found in coastal waters of the North Pacific, with the largest population in the eastern North Pacific. These whales winter along the coast of Baja, California, both along the coast and inside several breeding lagoons. They migrate north along the Pacific coast to feeding grounds in the Bering Sea in the spring. They are opportunistic foragers, feeding on small crustaceans and worms found in bottom sediments. They travel at 3-6 miles per hour (4.8-9.6 km/hr) and can stay submerged for up to 15 minutes.
Gray whales have a streamlined, mottled, gray body, commonly covered with barnacles. They lack a dorsal fin but have a prominent dorsal hump followed by a series of 6-12 “knuckles” that extend along the whale’s back to the flukes. Maximum length of the gray whale is 14.1 m (46 ft); females are slightly larger than the males.
The gray whale’s vocal repertoire includes rapid, rhythmic pulses and frequency- modulated signals. Eastern North Pacific gray whale calls (40 Hz- 4 kHz) have been detected throughout their range and across all seasons. Calls tend to peak during early morning and evening. The most abundant sound produced by the gray whales in their breeding lagoons is a low-frequency, pulsed “S1” (knock) call, which is produced in “bursts” or “bouts”. Individual pulses range in frequency between 100 and 1600 Hz, grouped in sets of 3-18 pulses per call. While migrating, gray whales primarily produce a frequency-modulated, low frequency moan, the “S3” call. Other gray whale calls have been described as rumbles, growls, chirps, clicks, croaks, belches, grunts, and bubble blasts, and are summarized in the table below. Gray whale calls can also be “mixed” and include more than one call-type. The function or behavioral context for any of these calls is unknown.
Because of their coastal habitat, especially along their migration route, gray whales are often in contact with human activities and are exposed to a wide range of natural and anthropogenic sounds. During playback studies of underwater noise sources, gray whales modify their calling behavior in a variety of ways as noise increased. They also changed swimming speed, foraging activity, and surface behaviors in the presence of noise.
Summary Table: Gray Whale Call Types:
|Call||Type||Frequency Range||Average Duration||Other names|
|S1 (M1 or N1)||Pulsed (3-18 pulses/call)||90 to 1600 Hz; peak freq. 200 to 800 Hz||5.9 pulses/s; call duration 1.8 s||
“knocks”, “bongo calls”
|S3 (M3)||Frequency-modulated sweep||100 to 300 Hz; peak freq. below 100 Hz||1.5 to 2 s||“low frequency moan”|
|S4 (M4)||Pulsed (clustered)||100 to 1500 Hz; peak freq. 150 to 300 Hz||0.2 to 1.5 s||“grunts”, “burps”, “purrs”|
|S8||Pulsed (higher repetition rate than S1)||51 to 185 Hz||14 pulses/s||“Quejido”|
|S9||Frequency modulated (with up to four harmonics)||55- 83 Hz||1.5 s||“Ronrroneo”|
- American Cetacean Society Fact Sheet: Gray Whale.
- Wisdom, S., Bowles, A. E., & Anderson, K. E. (2001). Development of behavior and sound repertoire of a rehabilitating gray whale calf. Aquatic Mammals, 27(3), 239–255.
- Richardson, W. J., Green, C. R., Malme, C. I. J., & Thomson, D. H. (1995). Marine Mammals and Noise. San Diego: Academic Press.
- National Marine Mammal Laboratory: Gray Whales.
- The Marine Mammal Center: Gray Whale.
- Scripps Institution of Oceanography, Voices in the Sea.
- Sounds of Gray Whales in Laguna San Ignacio, Laguna San Ignacio Ecosystem Science Project
Burnham, R., Duffus, D., & Mouy, X. (2018). Gray Whale (Eschrictius robustus) Call Types Recorded During Migration off the West Coast of Vancouver Island. Frontiers in Marine Science, 5, 329. https://doi.org/10.3389/fmars.2018.00329.
- Crane, N. L., & Lashkari, K. (1996). Sound production of gray whales, Eschrichtius robustus , along their migration route: A new approach to signal analysis. The Journal of the Acoustical Society of America, 100(3), 1878–1886. https://doi.org/10.1121/1.416006.
- Cummings, W. C., Thompson, P. O., & Cook, R. (1968). Underwater sounds of migrating gray whales, Eschrichtius glaucus (Cope). The Journal of the Acoustical Society of America, 44(5), 1278–1281. https://doi.org/10.1121/1.1911259.
- Dahlheim, M., & Castellote, M. (2016). Changes in the acoustic behavior of gray whales Eschrichtius robustus in response to noise. Endangered Species Research, 31, 227–242. https://doi.org/10.3354/esr00759.
- Guazzo, R. A., Helble, T. A., D’Spain, G. L., Weller, D. W., Wiggins, S. M., & Hildebrand, J. A. (2017). Migratory behavior of eastern North Pacific gray whales tracked using a hydrophone array. PLOS ONE, 12(10), e0185585. https://doi.org/10.1371/journal.pone.0185585.
- López-Urbán, A., Thode, A., Durán, C. B., UrbáN-R, J., & Swartz, S. (2018). Two new grey whale call types detected on bioacoustic tags. Journal of the Marine Biological Association of the United Kingdom, 98(5), 1169–1175. https://doi.org/10.1017/S0025315416001697.
- Moore, S. E., & Clarke, J. T. (2002). Potential impact of offshore human activities on gray whales (Eschrichtius robustus). Journal of Cetacean Research and Management, 4(1), 19–25.
- Ponce, D., Thode, A. M., Guerra, M., Urbán R., J., & Swartz, S. (2012). Relationship between visual counts and call detection rates of gray whales (Eschrichtius robustus) in Laguna San Ignacio, Mexico. The Journal of the Acoustical Society of America, 131(4), 2700–2713. https://doi.org/10.1121/1.3689851.
- Stafford, K. M., Moore, S., Spillane, M., & Wiggins, S. (2007). Gray whale calls recorded near Barrow, Alaska, throughout the winter of 2003-04. Arctic, 60(2), 167–172.