Underwater vocalizations of a male Pacific harbor seal (Phoca vitulina richardii) during a
mating period at Brookfield Zoo, Chicago IL
Mehgan M. ClarkJeanette Thomas
Western Illinois University
BackgroundEcology (Riedman, 1990)
Distribution (P.v.richardii) Alaska to Mexico
Diet-Amphibious Carnivore Fish, cephalopods, krill
Life Span 25 years in the wild
Maturity Females: 3-7 yrs Males: 2-7 yrs
https://www.washington.edu/burkemuseum/collections/mammalogy/mamwash/p
hvi.html
BackgroundMating Behavior (Riedman, 1990)
Males Dominance Hierarchy Aggressive Behavior
Flipper Slaps Neck Bites
Territory Vocalize Along travel corridor Possible lek (Van Parijs et al 1997)
Females Post-Partum
Estrus Annually March-
Sept. Feeding trips Aquatic Mating
Exact method not observed
Background-Acoustic Studies
Females Mother-pup relations
(Khan et al., 2006)
Males Breeding season (Van
Parijs et al., 1997; Hanggi and Schusterman, 1994)
Announce breading readiness and dominance hierarchy (Hayes et al., 2002)
http://photos.aznightbuzz.com/gallery/view/1544
Background-Harbor Seal Acoustics
Roars Hanggi and
Schusterman 1994 Mean 4.2 seconds Occasional
Harmonics Van Parijs et al. 1997
1/min 1 roar underwater Mean = 665 Hz
Van Parijs et al. 2003 Geographic variation
Hearing Range (Fay 1988) Phocids have a greatest
sensitivity between about 1 and 60 kHz
http://www.brookfieldzoo.org/pagegen/images/fix/sealcut.jpg
Goals
Catalog all sounds as part of the repertoire.
Determine if the calls are different.
Determine the number of calls per minute.
Photo By: Mehgan Clark
Materials
Ithaco 605 Hydrophone Linear to 75 kHz
DELL XPS M140 Laptop. Linear to 48 kHz
Goldwave sound analysis program and recording software.
Spectrogram sound analysis program. Photo By: Mehgan Clark
Methods Recordings
April and October 2006
6-10AM Behavioral
Notes Taken as Possible
Limited Stats
Summary Stats PCA Hierarchical Cluster
Photo By: Dr. J. A. Thomas
Component One
Dominant Beginning Frequency Dominant
Minimum Frequency
Dominant Maximum Frequency
Dominant Ending
Frequency
Long Roar Short Roar
Growl
Results-Calls
3 Main Calls (n=713 calls) Growls Short Roars Long Roars
Found only during the mating period June 25-28 2006 Probable start End of behavior date
unknown Phase 4 of Study 2.5 Calls per Minute 98.6% of repertoire One-Way ANOVA
Dominant Maximum Frequency (p=0.377, df=93, alpha=0.05)
Call Parameter Means + Standard Deviations
1.84±0.65
336.5±148.1
1349.8±452.1
797.2±210.2
727.2±133.7
Short Roar
4.80±1.77
210.6±18.4
1329.3±319.8
707.5±191.1
611.3±98.8
Long Roar
0.94±0.55
291.2±163.1
2060.2±566.6
1026.1±325.2
1026.1±315.1
Growl
ComponentDuration(seconds)
Dom. Min. Freq. (Hz)
Dom. Max. Freq.(Hz)
Dom. Ending Freq.(Hz)
Dom. Beg.Freq.(Hz)
Call Type
Principal Component AnalysisComponent Loadings Factor 1 Factor 2 Factor 3Dominant Beginning Frequency -0.922 0.213 0.289Dominant Ending Frequency -0.916 0.225 0.287Dominant Maximum Frequency -0.865 0.177 0.285Dominant Minimum Frequency -0.602 0.122 0.067Component Duration 0.573 0.002 0.742Total Duration 0.566 -0.069 0.752Presence/Absence 0.216 0.849 -0.132of HarmonicsFirst Harmonic Interval 0.262 0.941 -0.001Highest Harmonic 0.252 0.93 -0.022
Variance Explained 3.627 2.635 1.385by Components
Percent of Total 40.297 29.281 15.393Variance Explained
0.000 Distances 5000.000
Hierarchical Clustering
Click
Short Roar
Grunt
Growl
Groan
Howl
Whistle
Long Roar
Creak
Conclusions
Differences in 3 Call types. Statistically Significant Support Literature Frequency Components
Most Important Male vocalization
roar-associated with mating behavior
blowing bubbles selection by female
No other males May rule-out that it is a
competition call
Photo By: Mehgan Clark
Future Research
Similar Research Video Recordings Simultaneous
with acoustic recording
Surface intervals Number of roars
per dive Behavioral
Components
Literature CitedHanggi, E. B. and Schusterman, R.J. 1994. Underwater acoustic displays and individual variation
in male Harbour Seals, Phoca vitulina. Animal Behavoiur 48: 1275-1283
Hayes, S.A, A. Kumar, D.P. Costa, D.K Mellinger, J.T. Harvey, B. L. Southall, and B.J. Le Boeuf. 2002. Evaluating the function of the male harbour seal, Phoca vitulina, roar through playback experiments. Animal Behaviour 67: 1133-1139
Khan, C. B., H. Markowitz, and B. McCowan. 2006. Vocal development in captive harbor seal pups, Phoca vitulina richardii: Age, sex, and individual differences. J. Acoust. Soc. Am. 120 (3):1684-1694.
Le Boeuf, B. J. Pinniped mating systems on land, ice and in the water: Emphasis on the Phocidae. in D. Renouf ed. Behavior of Pinnipeds. Chapman and Hall New York, NY.
Poulter, T. C. 1963. Sonar Signals of the Sea Lion. Science 139: 753-754.
Riedman, M. 1990. The Pinnipeds: Seals, Sea Lions and Walruses. University of California Press, Berkley, CA.
Schusterman et al. 2000. Why pinnipeds don’t echolocate. J. Acoust. Soc. Am. 107 (4): 2256-2264
Van Parijs, S.M., P.M. Thompson,. D.J. Tollit and A. Mackay. 1997. Distribution and activity of male harbour seals during the mating season. Animal Behavior 54: 35-43
Van Parijs, S.M. et al. 2003. Patterns in the vocalizations of male Harbor Seals. J. Acoust. Soc. Am. 113 (6): 3403-3410
Van Parijs, S.M., G.D. Hastie, and P.M. Thompson. 2000. Individual and geographical variation in
display behaviour of male harbour seals in Scotland. Animal Behaviour 59: 559-568
Acknowledgments
Dr. Jeanette Thomas Jennifer McGee, Rita Stacey, Wendy
Komar, Brookfield Zoo Staff Dr. Musser and Dr. Meiers Matthew Clark Fellow Graduate Students
Questions?