Animal Cognition

, Volume 11, Issue 2, pp 319–327 | Cite as

Novel sound production through contingency learning in the Pacific walrus (Odobenus rosmarus divergens)

Original Paper

Abstract

Walruses (Odobenus rosmarus) are highly vocal amphibious mammals with a range of anatomical specializations that can provide plasticity to their sound emissions. The objective of this descriptive study was to determine whether contingency learning could be used to increase variability and induce novelty in the acoustic behavior of walruses. The subjects were two twelve-year-old captive walruses, a male and a female that had previously been conditioned using food reinforcement to produce several specific sounds in response to different discriminative cues. In the current task, these individuals were encouraged to produce novel sounds and novel sound combinations in air by withholding reinforcement for sounds previously emitted in a given session and providing reinforcement only for qualitative differences in emitted sounds. Following training in air, the walruses were tested under water with the same reinforcement contingency. The subjects responded as they had done in air, by varying their underwater sound emissions until reinforcement was provided. Many of the sounds and sound combinations produced by the subjects during underwater testing were quite different from those produced during training in air and those produced under water during baseline observations. Both the male and female spontaneously emitted knocks and soft bells which are components of the songs known to be emitted by mature male walruses during the breeding season. The finding that reinforced variability can induce creativity in sound production is consistent with recent experiments on budgerigar birds showing that vocal topographies, like motor responses, may be influenced by contingency learning.

Keywords

Pacific walrus Odobenus rosmarus divergens Sound production Vocal behavior Vocal learning Creativity 

Notes

Acknowledgments

We gratefully acknowledge the management of Six Flags Marine World for providing us with access to their walruses; we are especially indebted to Debbie Quihuis for providing invaluable animal training, research assistance, and walrus expertise at the park. We thank the research team at the Pinniped Cognition and Sensory Systems Lab at Long Marine Laboratory for their encouragement with this work, especially Marla Holt for support with acoustic analyses, Jon Brininger for audio-video support, and Kristy Lindemann for assistance with data collection. Sue Negrini provided very helpful information and ideas that contributed to the design of this study. This work was supported in part by Office of Naval Research grant N00014-06-447505. The experiments described herein comply with the current laws of the United States.

Supplementary material

10071_2007_120_MOESM1_ESM.wmv (287 kb)
S1A. The underwater sounds corresponding to the spectrograms shown in Figure 1 for the male walrus, Sivuqaq (WMV 287 kb)
10071_2007_120_MOESM2_ESM.wmv (233 kb)
S1B. The underwater sounds corresponding to the spectrograms shown in Figure 1 for the male walrus, Sivuqaq (WMV 233 kb)
10071_2007_120_MOESM3_ESM.wmv (65 kb)
S1C. The underwater sounds corresponding to the spectrograms shown in Figure 1 for the male walrus, Sivuqaq (WMV 65 kb)
10071_2007_120_MOESM4_ESM.wmv (139 kb)
S1D. The underwater sounds corresponding to the spectrograms shown in Figure 1 for the male walrus, Sivuqaq (WMV 139 kb)
10071_2007_120_MOESM5_ESM.wmv (256 kb)
S1E. The underwater sounds corresponding to the spectrograms shown in Figure 1 for the male walrus, Sivuqaq (WMV 256 kb)
10071_2007_120_MOESM6_ESM.wmv (361 kb)
S1F. The underwater sounds corresponding to the spectrograms shown in Figure 1 for the male walrus, Sivuqaq (WMV 361 kb)
10071_2007_120_MOESM7_ESM.wmv (277 kb)
S2A. The underwater sounds corresponding to the spectrograms shown in Figure 2 for the female walrus, Siku (WMV 278 kb)
10071_2007_120_MOESM8_ESM.wmv (188 kb)
S2B. The underwater sounds corresponding to the spectrograms shown in Figure 2 for the female walrus, Siku (WMV 189 kb)
10071_2007_120_MOESM9_ESM.wmv (272 kb)
S2C. The underwater sounds corresponding to the spectrograms shown in Figure 2 for the female walrus, Siku (WMV 273 kb)
10071_2007_120_MOESM10_ESM.wmv (665 kb)
S2D. The underwater sounds corresponding to the spectrograms shown in Figure 2 for the female walrus, Siku (WMV 666 kb)
10071_2007_120_MOESM11_ESM.wmv (857 kb)
S2E. The underwater sounds corresponding to the spectrograms shown in Figure 2 for the female walrus, Siku (WMV 858 kb)

S3. Video samples from an in-air training session with the male walrus Sivuqaq. Note the highly graded sound emissions, the rapid transitions from one sound type to another, and the variety of structures with which the sounds are produced (WMV 3660 kb)

S4. Video recording of the male walrus Sivuqaq during his first underwater testing session. Chugging sounds, moans, and knocks are audible (WMV 1930 kb)

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Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  1. 1.Institute of Marine SciencesUniversity of California Santa CruzSanta CruzUSA
  2. 2.UCSC Long Marine LaboratorySanta CruzUSA

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