The determination of sex by simple observation is often difficult in marine mammals, even in sexually dimorphic species. Moreover, there is often the practical necessity to determine sex in samples that have been coll...The determination of sex by simple observation is often difficult in marine mammals, even in sexually dimorphic species. Moreover, there is often the practical necessity to determine sex in samples that have been collected without handling or observing the subjects. In these cases, a molecular assay for sex determination is required. We adapted an assay that targets the zinc-finger region and is based on a single primer pair, to the Guadalupe fur seal, a near threatened species that has a very limited breeding range. First, we validated the assay with a sample of pups in which we determined the sex by direct observation during handling;second, we compared it to a more recent assay, based on two different primer pairs and, finally, we evaluated the effect of DNA quantity on its reliability. The assay that we tested produced excellent results and was more reliable than the other one based on two primers. Reliable results were also obtained when only remarkably small quantities of DNA were amplified. These results show the potential use of this molecular assay in case of non-invasive sampling, an overly common situation when dealing with species of problematic conservation status.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
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
文摘The determination of sex by simple observation is often difficult in marine mammals, even in sexually dimorphic species. Moreover, there is often the practical necessity to determine sex in samples that have been collected without handling or observing the subjects. In these cases, a molecular assay for sex determination is required. We adapted an assay that targets the zinc-finger region and is based on a single primer pair, to the Guadalupe fur seal, a near threatened species that has a very limited breeding range. First, we validated the assay with a sample of pups in which we determined the sex by direct observation during handling;second, we compared it to a more recent assay, based on two different primer pairs and, finally, we evaluated the effect of DNA quantity on its reliability. The assay that we tested produced excellent results and was more reliable than the other one based on two primers. Reliable results were also obtained when only remarkably small quantities of DNA were amplified. These results show the potential use of this molecular assay in case of non-invasive sampling, an overly common situation when dealing with species of problematic conservation status.
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.
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.
