Vocal communication is a crucial aspect of animal behavior. The mechanism which most mam- mals use to vocalize relies on three anatomical components. First, air overpressure is generated in- side the lower vocal tract...Vocal communication is a crucial aspect of animal behavior. The mechanism which most mam- mals use to vocalize relies on three anatomical components. First, air overpressure is generated in- side the lower vocal tract. Second, as the airstream goes through the glottis, sound is produced via vocal fold vibration. Third, this sound is further filtered by the geometry and length of the upper vocal tract. Evidence from mammalian anatomy and bioacoustics suggests that some of these three components may covary with an animal＇s body size. The framework provided by acoustic al- Iometry suggests that, because vocal tract length （VTL） is more strongly constrained by the growth of the body than vocal fold length （VFL）, VTL generates more reliable acoustic cues to an animal＇s size. This hypothesis is often tested acoustically but rarely anatomically, especially in pinnipeds. Here, we test the anatomical bases of the acoustic allometry hypothesis in harbor seal pups Phoca vitulina. We dissected and measured vocal tract, vocal folds, and other anatomical features of 15 harbor seals post-mortem. We found that, while VTL correlates with body size, VFL does not. This suggests that, while body growth puts anatomical constraints on how vocalizations are filtered by harbor seals＇ vocal tract, no such constraints appear to exist on vocal folds, at least during puppy- hood. It is particularly interesting to find anatomical constraints on harbor seals＇ vocal tracts, the same anatomical region partially enabling pups to produce individually distinctive vocalizations.展开更多
Puppyhood is a very active social and vocal period in a harbor seal's life Ph oca vitulina. An important feature of vocalizations is their temporal and rhythmic structure, and understanding vocal timing and rhythm...Puppyhood is a very active social and vocal period in a harbor seal's life Ph oca vitulina. An important feature of vocalizations is their temporal and rhythmic structure, and understanding vocal timing and rhythms in harbor seals is critical to a cross-species hypothesis in evolutionary neuroscience that links vocal learning, rhythm perception, and synchronization. This study utilized analytical techniques that may best capture rhythmic structure in pup vocalizations with the goal of examining whether (1) harbor seal pups show rhythmic structure in their calls and (2) rhythms evolve over time. Calls of 3 wild-born seal pups were recorded daily over the course of 1-3 weeks;3 temporal features were analyzed using 3 complementary techniques. We identified temporal and rhythmic structure in pup calls across different time windows. The calls of harbor seal pups exhibit some degree of temporal and rhythmic organization, which evolves over puppyhood and resembles that of other species' in teractive comm un icati on. We suggest n ext steps for investigating call structure in harbor seal pups and propose comparative hypotheses to test in other pinniped species.展开更多
文摘Vocal communication is a crucial aspect of animal behavior. The mechanism which most mam- mals use to vocalize relies on three anatomical components. First, air overpressure is generated in- side the lower vocal tract. Second, as the airstream goes through the glottis, sound is produced via vocal fold vibration. Third, this sound is further filtered by the geometry and length of the upper vocal tract. Evidence from mammalian anatomy and bioacoustics suggests that some of these three components may covary with an animal＇s body size. The framework provided by acoustic al- Iometry suggests that, because vocal tract length （VTL） is more strongly constrained by the growth of the body than vocal fold length （VFL）, VTL generates more reliable acoustic cues to an animal＇s size. This hypothesis is often tested acoustically but rarely anatomically, especially in pinnipeds. Here, we test the anatomical bases of the acoustic allometry hypothesis in harbor seal pups Phoca vitulina. We dissected and measured vocal tract, vocal folds, and other anatomical features of 15 harbor seals post-mortem. We found that, while VTL correlates with body size, VFL does not. This suggests that, while body growth puts anatomical constraints on how vocalizations are filtered by harbor seals＇ vocal tract, no such constraints appear to exist on vocal folds, at least during puppy- hood. It is particularly interesting to find anatomical constraints on harbor seals＇ vocal tracts, the same anatomical region partially enabling pups to produce individually distinctive vocalizations.
文摘Puppyhood is a very active social and vocal period in a harbor seal's life Ph oca vitulina. An important feature of vocalizations is their temporal and rhythmic structure, and understanding vocal timing and rhythms in harbor seals is critical to a cross-species hypothesis in evolutionary neuroscience that links vocal learning, rhythm perception, and synchronization. This study utilized analytical techniques that may best capture rhythmic structure in pup vocalizations with the goal of examining whether (1) harbor seal pups show rhythmic structure in their calls and (2) rhythms evolve over time. Calls of 3 wild-born seal pups were recorded daily over the course of 1-3 weeks;3 temporal features were analyzed using 3 complementary techniques. We identified temporal and rhythmic structure in pup calls across different time windows. The calls of harbor seal pups exhibit some degree of temporal and rhythmic organization, which evolves over puppyhood and resembles that of other species' in teractive comm un icati on. We suggest n ext steps for investigating call structure in harbor seal pups and propose comparative hypotheses to test in other pinniped species.
