Somatosensation, Echolocation, and Underwater Sniffing: Adaptations Allow Mammals Without Traditional Olfactory Capabilities to Forage for Food Underwater

Marriott, Sarah; Cowan, Emily; Cohen, J.; Hallock, Robert M.

doi:10.2108/zsj.30.69

Cited by 11 publications

(9 citation statements)

References 48 publications

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“…Dolphins are large-brained, highly gyrencephalic, long-living mammals endowed with high cognitive abilities and sophisticated navigation systems ( Marriott et al, 2013 ). The adaptation to aquatic life promoted the evolution of features (echolocation, composite language, capacity to elaborate intricate social skills) related to their ecological niche and sometimes similar in complexity to humans ( Cozzi et al, 2017 ; van Kann et al, 2017 ).…”

Section: Absence Of Postnatal Neurogenesis In the Dolphin Brainmentioning

confidence: 99%

“…Fish have olfaction and olfactory systems similar to that of other vertebrates, supporting behaviors crucial for survival ( Kermen et al, 2013 ). Instead, dolphins have developed echolocation for navigation, foraging, and tracking of prey ( Marriott et al, 2013 ), thus, unlike terrestrial mammals (and fish), toothed whales have completely lost olfaction ( Oelschläger, 2008 ; Cozzi et al, 2017 ). Since the SVZ of the lateral ventricles provides neuronal progeny destined for the OB and linked to olfactory discrimination ( Lledo and Valley, 2016 ; Zhuo et al, 2016 ), we investigated the periventricular region of neonatal and adult dolphins in search for neurogenic activity.…”

Section: Absence Of Postnatal Neurogenesis In the Dolphin Brainmentioning

confidence: 99%

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Humans and Dolphins: Decline and Fall of Adult Neurogenesis

2018

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Pre-clinical research is carried out on animal models, mostly laboratory rodents, with the ultimate aim of translating the acquired knowledge to humans. In the last decades, adult neurogenesis (AN) has been intensively studied since it is viewed as a tool for fostering brain plasticity, possibly repair. Yet, occurrence, location, and rate of AN vary among mammals: the capability for constitutive neuronal production is substantially reduced when comparing small-brained, short living (laboratory rodents) and large-brained, long-living species (humans, dolphins). Several difficulties concerning scarce availability of fresh tissues, technical limits and ethical concerns did contribute in delaying and diverting the achievement of the picture of neurogenic plasticity in large-brained mammals. Some reports appeared in the last few years, starting to shed more light on this issue. Despite technical limits, data from recent studies mostly converge to indicate that neurogenesis is vestigial, or possibly absent, in regions of the adult human brain where in rodents neuronal addition continues into adult life. Analyses carried out in dolphins, mammals devoid of olfaction, but descendant of ancestors provided with olfaction, has shown disappearance of neurogenesis in both neonatal and adult individuals. Heterogeneity in mammalian structural plasticity remains largely underestimated by scientists focusing their research in rodents. Comparative studies are the key to understand the function of AN and the possible translational significance of neuronal replacement in humans. Here, we summarize comparative studies on AN and discuss the evolutionary implications of variations on the recruitment of new neurons in different regions and different species.

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Section: Absence Of Postnatal Neurogenesis In the Dolphin Brainmentioning

confidence: 99%

Section: Absence Of Postnatal Neurogenesis In the Dolphin Brainmentioning

confidence: 99%

Humans and Dolphins: Decline and Fall of Adult Neurogenesis

2018

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“…This has led to the majority of studies addressing questions related to hearing, sound production, echolocation and related communicative activities. By contrast, other sensory modalities are considered to be less important (e.g., Marriott et al, 2013) and, therefore, have become physically reduced or may even be absent due to complex trade-offs between different sensory modalities (Nummela et al, 2013). This approach appears biased and runs the risk of distorting knowledge or oversimplifying the degree by which dolphins, and other cetacean, might possess and utilize a potentially diverse array of senses.…”

Section: Resultsmentioning

confidence: 99%

Sensory Perception in Cetaceans: Part I—Current Knowledge about Dolphin Senses As a Representative Species

et al. 2016

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A large part of the literature on sensory perception and behavior in dolphins is devoted to its well-developed vocal and echolocation abilities. In this review, we aim to augment current knowledge by examining the literature on dolphins' entire "Merkwelt" (which refers to everything a subject perceives, creating a crucial part of the subject's Umwelt). We will show that despite extensive knowledge on audition, aspects such as context relatedness, the social function of vocalizations or socio-sexual recognition, remain poorly understood. Therefore, we propose areas for further lines of investigation. Recent studies have shown that the sensory world of dolphins might well be much more diverse than initially thought. Indeed, although underwater and aerial visual systems differ in dolphins, they have both been shown to be important. Much debated electro-and magnetoreception appear to be functional senses according to recent studies. Finally, another neglected area is chemoreception. We will summarize neuroanatomical and physiological data on olfaction and taste, as well as corresponding behavioral evidence. Taken together, we will identify a number of technical and conceptual reasons for why chemosensory data appear contradictory, which is much debated in the literature. In summary, this article aims to provide both an overview of the current knowledge on dolphin perception, but also offer a basis for further discussion and potential new lines of research.Keywords: cetaceans, Delphinidae, Tursiops truncatus, audition, vision, electroreception, magnetoreception, chemoreception DOLPHIN'S UMWELT Sensory perception is essential for the survival of organisms, be it for the detection of (un)favorable physical conditions, the presence/absence of food or predators, the detection of communication signals or the recognition of social partners. It is crucial for any species to perceive regularities and changes in the properties of their abiotic and biotic environment.

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“…Its use in sensing may also be possible. There are a few demonstrations of olfactory sensations being used by animals underwater [89], including harbor seals detecting dimethyl sulfide, which can indicate profitable foraging areas [78]. However, pinnipeds are generally considered microsmatic (having a poor sense of smell) [88].…”

Section: Olfactionmentioning

confidence: 99%

“…Sharks can detect electric fields [73]. The starnosed mole and water shrew are able to sniff and detect semiochemicals underwater [89]. Crocodiles have dome-shaped pressure receptors distributed across their face.…”

Section: With Hairlike Structuresmentioning

confidence: 99%

Passive wake detection using seal whisker-inspired sensing

Beem¹

2015

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This thesis is motivated by a series of biological experiments that display the harbor seal's extraordinary ability to track the wake of an object several seconds after it has swum by. They do so despite having auditory and visual cues blocked, pointing to use of their whiskers as sensors of minute water movements. In this work, I elucidate the basic fluid mechanisms that seals may employ to accomplish this detection. Key are the unique flow-induced vibration properties resulting from the geometry of the harbor seal whisker, which is undulatory and elliptical in cross-section.First, the vortex-induced vibration (VIV) characteristics of the whisker geometry are tested. Direct force measurements and flow visualizations on a rigid whisker model undergoing a range of 1-D imposed oscillations show that the geometry passively reduces VIV (factor of > 10), despite contributions from effective added mass and damping. Next, a biomimetic whisker sensor is designed and fabricated. The rigid whisker model is mounted on a four-armed flexure, allowing it to freely vibrate in both in-line and crossflow directions. Strain gauges on the flexure measure deflections at the base. Finally, this device is tested in a simplified version of the fish wake -seal whisker interaction scenario. The whisker is towed behind an upstream cylinder with larger diameter. Whereas in open water the whisker exhibits very low vibration when its long axis is aligned with the incoming flow, once it enters the wake it oscillates with large amplitude and its frequency coincides with the Strouhal frequency of the upstream cylinder. This makes the detection of an upstream wake as well as an estimation of the size of the wake-generating body possible. A slaloming motion among the wake vortices causes the whisker to oscillate in this manner. The same mechanism has been previously observed in energy-extracting foils and trout actively swimming behind bluff cylinders in a stream. Dave, Jason, Gabe, Pablo, Remi, and Yahya were postdocs when we first met.Thank you for being approachable and sharing much needed advice all along the way.Your love of science has inspired me to be more inquisitive.Brandon, Chris, Matthew, and Patrick were undergrads or high school students who spent their summers working in the Tow Tank with me. Thanks for giving me the chance to practice being a mentor, moving this research forward a lot faster than I could do on my own, and helping me lift the mega-whisker in and out of the tank! May you all keep on building and exploring.Thanks to Kathy Streeter and the New England Aquarium staff for helping me understand more about real harbor seals. They graciously collected shed whisker specimens and allowed me to take many close-up pictures of their seals.Thanks to all the people who helped me prepare for and make it through research cruises: Eric Hayden, Terry Hammar, and Hanu Singh for contributing their expertise 5 to help me make my first ocean-ready sensor, all parties involved in the first UNOLS Chief Scientist Training Cruise se...

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Somatosensation, Echolocation, and Underwater Sniffing: Adaptations Allow Mammals Without Traditional Olfactory Capabilities to Forage for Food Underwater

Cited by 11 publications

References 48 publications

Humans and Dolphins: Decline and Fall of Adult Neurogenesis

Humans and Dolphins: Decline and Fall of Adult Neurogenesis

Sensory Perception in Cetaceans: Part I—Current Knowledge about Dolphin Senses As a Representative Species

Passive wake detection using seal whisker-inspired sensing

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