Hydrodynamic Trail-Following in Harbor Seals (
            <i>Phoca vitulina</i>
            )

Dehnhardt, Guido; Mauck, Björn; Hanke, Wolf; Bleckmann, Horst

doi:10.1126/science.1060514

Cited by 333 publications

(280 citation statements)

References 11 publications

Supporting

Mentioning

271

Contrasting

Unclassified

Order By: Relevance

“…These findings emphasize that, in addition to vision, the well-developed nonvisual sensory modalities (e.g. hearing, tactile-vibrissae sensitivity) are probably also of great importance to pinnipeds under water (Schusterman et al 2000;Dehnhardt et al 2001). …”

Section: Discussionmentioning

confidence: 73%

Visual pigments of marine carnivores: pinnipeds, polar bear, and sea otter

et al. 2006

View full text Add to dashboard Cite

Rod and cone visual pigments of 11 marine carnivores were evaluated. Rod, middle/long-wavelength sensitive (M/L) cone, and short-wavelength sensitive (S) cone opsin (if present) sequences were obtained from retinal mRNA. Spectral sensitivity was inferred through evaluation of known spectral tuning residues. The rod pigments of all but one of the pinnipeds were similar to those of the sea otter, polar bear, and most other terrestrial carnivores with spectral peak sensitivities (k max ) of 499 or 501 nm. Similarly, the M/L cone pigments of the pinnipeds, polar bear, and otter had inferred k max of 545 to 560 nm. Only the rod opsin sequence of the elephant seal had sensitivity characteristic of adaptation for vision in the marine environment, with an inferred k max of 487 nm. No evidence of S cones was found for any of the pinnipeds. The polar bear and otter had S cones with inferred k max of $440 nm. Flickerphotometric ERG was additionally used to examine the in situ sensitivities of three species of pinniped. Despite the use of conditions previously shown to evoke cone responses in other mammals, no cone responses could be elicited from any of these pinnipeds. Rod photoreceptor responses for all three species were as predicted by the genetic data.

show abstract

Section: Discussionmentioning

confidence: 73%

Visual pigments of marine carnivores: pinnipeds, polar bear, and sea otter

et al. 2006

View full text Add to dashboard Cite

show abstract

“…Seals in general, and especially the harp seal (Pagophilus groenlandicus), are known to be very vocal (Hanggi and Schusterman, 1994;Rogers et al, 1996). Also, they are known to rely on both chemical and tactile signals as well as their vision (Kovacs, 1987;Davis et al, 1999;Dehnhardt et al, 2001).…”

mentioning

confidence: 99%

A Neurological Comparative Study of the Harp Seal (Pagophilus groenlandicus) and Harbor Porpoise (Phocoena phocoena) Brain

Walløe

Eriksen

Dabelsteen

et al. 2010

The Anatomical Record

View full text Add to dashboard Cite

The cetacean brain is well studied. However, few comparisons have been done with other marine mammals. In this study, we compared the harp seal (Pagophilus groenlandicus) and the harbor porpoise brain (Phocoena phocoena). Stereological methods were applied to compare three areas of interest: the entire neocortex and two subdivisions of the neocortex, the auditory and visual cortices. The total number of neurons and glial cells in the three regions was estimated. The main results showed that the harbor porpoise have an estimated 14.9 Â 10 9 neocortical neurons and 34.8 Â 10 9 neocortical glial cells, whereas the harp seal have 6.1 Â 10 9 neocortical neurons and 17.5 Â 10 9 neocortical glial cells. The harbor porpoise have significantly more neurons and glial cells in the auditory cortex than in the visual cortex, whereas the pattern was opposite for the harp seal. These results are the first to provide estimates of the number of neurons and glial cells in the neocortex of the harp seal and harbor porpoise brain and offer new data to the comparative field of mammalian brain evolution. Anat Rec, 293:2129Rec, 293: -2135

show abstract

“…As many aquatic mammals need to hunt at night or in turbid or deep water, their sensory systems have accordingly evolved. Pinnipeds developed longer and more sensitive vibrissae that can pick up hydrodynamic trails (vibrations in water) of fish swimming, or relay information about water current flow and variations in substrate surfaces (Dehnhardt et al, 2001). Odontocetes (toothed whales) developed nasal structures that generate echolocation, enabling them to use sound to locate prey or navigate past obstacles (Cranford et al, 1996;Au et al, 2006).…”

mentioning

confidence: 99%

Anatomical adaptations of aquatic mammals

Reidenberg

2007

The Anatomical Record

118

105

View full text Add to dashboard Cite

This special issue of the Anatomical Record explores many of the anatomical adaptations exhibited by aquatic mammals that enable life in the water. Anatomical observations on a range of fossil and living marine and freshwater mammals are presented, including sirenians (manatees and dugongs), cetaceans (both baleen whales and toothed whales, including dolphins and porpoises), pinnipeds (seals, sea lions, and walruses), the sea otter, and the pygmy hippopotamus. A range of anatomical systems are covered in this issue, including the external form (integument, tail shape), nervous system (eye, ear, brain), musculoskeletal systems (cranium, mandible, hyoid, vertebral column, flipper/forelimb), digestive tract (teeth/tusks/baleen, tongue, stomach), and respiratory tract (larynx). Emphasis is placed on exploring anatomical function in the context of aquatic life. The following topics are addressed: evolution, sound production, sound reception, feeding, locomotion, buoyancy control, thermoregulation, cognition, and behavior. A variety of approaches and techniques are used to examine and characterize these adaptations, ranging from dissection, to histology, to electron microscopy, to two-dimensional (2D) and 3D computerized tomography, to experimental field tests of function. The articles in this issue are a blend of literature review and new, hypothesis-driven anatomical research, which highlight the special nature of anatomical form and function in aquatic mammals that enables their exquisite adaptation for life in such a challenging environment. Key words: aquatic; adaptation; anatomy; marine mammal; sirenian; cetacean; pinniped; evolution Aquatic life poses many challenges for mammals that were originally adapted for life on land. As the evolutionary process of natural selection can only apply to modifying present structures, aquatic mammals bring a lot of terrestrial baggage to their aquatic existence. For one thing, they do not breathe water as fish do. Therefore, respiratory tract modifications are necessary to protect a system designed to function in air while excluding the ever-present surrounding water. Many of these adaptations have been previously described, for example, valvular nostrils that exclude water, and an intranarial larynx (Reidenberg and Laitman, 1987) that further protects the respiratory tract from water inundation during swallowing. Diving presents additional challenges, as ambient pressure rises with increased depth. Lung volumes collapse under the high pressures of a deep dive (Boyd, 1975;Ridgway and Howard, 1979). A jointed, collapsible rib cage allows compression of the thorax to accommodate the shrinking lungs. Skeletal muscles are adapted to maintain low levels of aerobic metabolism under the hypoxic conditions associated with diving (Kanatous

show abstract

Hydrodynamic Trail-Following in Harbor Seals ( Phoca vitulina )

Cited by 333 publications

References 11 publications

Visual pigments of marine carnivores: pinnipeds, polar bear, and sea otter

Visual pigments of marine carnivores: pinnipeds, polar bear, and sea otter

A Neurological Comparative Study of the Harp Seal (Pagophilus groenlandicus) and Harbor Porpoise (Phocoena phocoena) Brain

Anatomical adaptations of aquatic mammals

Contact Info

Product

Resources

About