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Werth AJ, Crompton AW. Cetacean tongue mobility and function: A comparative review. J Anat 2023; 243:343-373. [PMID: 37042479 PMCID: PMC10439401 DOI: 10.1111/joa.13876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 03/26/2023] [Accepted: 03/27/2023] [Indexed: 04/13/2023] Open
Abstract
Cetaceans are atypical mammals whose tongues often depart from the typical (basal) mammalian condition in structure, mobility, and function. Their tongues are dynamic, innovative multipurpose tools that include the world's largest muscular structures. These changes reflect the evolutionary history of cetaceans' secondary adaptation to a fully aquatic environment. Cetacean tongues play no role in mastication and apparently a greatly reduced role in nursing (mainly channeling milk ingestion), two hallmarks of Mammalia. Cetacean tongues are not involved in drinking, breathing, vocalizing, and other non-feeding activities; they evidently play no or little role in taste reception. Although cetaceans do not masticate or otherwise process food, their tongues retain key roles in food ingestion, transport, securing/positioning, and swallowing, though by different means than most mammals. This is due to cetaceans' aquatic habitat, which in turn altered their anatomy (e.g., the intranarial larynx and consequent soft palate alteration). Odontocetes ingest prey via raptorial biting or tongue-generated suction. Odontocete tongues expel water and possibly uncover benthic prey via hydraulic jetting. Mysticete tongues play crucial roles driving ram, suction, or lunge ingestion for filter feeding. The uniquely flaccid rorqual tongue, not a constant volume hydrostat (as in all other mammalian tongues), invaginates into a balloon-like pouch to temporarily hold engulfed water. Mysticete tongues also create hydrodynamic flow regimes and hydraulic forces for baleen filtration, and possibly for cleaning baleen. Cetacean tongues lost or modified much of the mobility and function of generic mammal tongues, but took on noteworthy morphological changes by evolving to accomplish new tasks.
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Affiliation(s)
- Alexander J Werth
- Department of Biology, Hampden-Sydney College, Hampden-Sydney, Virginia, USA
| | - A W Crompton
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
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2
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Vandenberg ML, Cohen KE, Rubin RD, Goldbogen JA, Summers AP, Paig-Tran EWM, Kahane-Rapport SR. Formation of a fringe: A look inside baleen morphology using a multimodal visual approach. J Morphol 2023; 284:e21574. [PMID: 36807194 DOI: 10.1002/jmor.21574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 12/22/2022] [Accepted: 12/26/2022] [Indexed: 02/23/2023]
Abstract
Filter-feeding has been present for hundreds of millions of years, independently evolving in aquatic vertebrates' numerous times. Mysticete whales are a group of gigantic, marine filter-feeders that are defined by their fringed baleen and are divided into two groups: balaenids and rorquals. Recent studies have shown that balaenids likely feed using a self-cleaning, cross-flow filtration mechanism where food particles are collected and then swept to the esophagus for swallowing. However, it is unclear how filtering is achieved in the rorquals (Balaenopteridae). Lunging rorqual whales engulf enormous masses of both prey and water; the prey is then separated from the water through baleen plates lining the length of their upper jaw and positioned perpendicular to flow. Rorqual baleen is composed of both major (larger) and minor (smaller) keratin plates containing embedded fringe that extends into the whale's mouth, forming a filtering fringe. We used a multimodal approach, including microcomputed tomography (µCT) and scanning electron microscopy (SEM), to visualize and describe the variability in baleen anatomy across five species of rorqual whales, spanning two orders of magnitude in body length. For most morphological measurements, larger whales exhibited hypoallometry relative to body length. µCT and SEM revealed that the major and minor plates break away from the mineralized fringes at variable distances from the gums. We proposed a model for estimating the effective pore size to determine whether flow scales with body length or prey size across species. We found that pore size is likely not a proxy for prey size but instead, may reflect changes in resistance through the filter that affect fluid flow.
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Affiliation(s)
- Megan L Vandenberg
- Department of Biology, University of Washington, Seattle, Washington, USA
- Friday Harbor Laboratories, University of Washington, Friday Harbor, Washington, USA
| | - Karly E Cohen
- Department of Biology, University of Washington, Seattle, Washington, USA
- Friday Harbor Laboratories, University of Washington, Friday Harbor, Washington, USA
| | | | - Jeremy A Goldbogen
- Hopkins Marine Station, Stanford University, Pacific Grove, California, USA
| | - Adam P Summers
- Department of Biology, University of Washington, Seattle, Washington, USA
- Friday Harbor Laboratories, University of Washington, Friday Harbor, Washington, USA
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3
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Provini P, Brunet A, Filippo A, Van Wassenbergh S. In vivo intraoral waterflow quantification reveals hidden mechanisms of suction feeding in fish. eLife 2022; 11:73621. [PMID: 35192455 PMCID: PMC8906803 DOI: 10.7554/elife.73621] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Accepted: 02/21/2022] [Indexed: 11/13/2022] Open
Abstract
Virtually all fishes rely on flows of water to transport food to the back of their pharynx. While external flows that draw food into the mouth are well described, how intra-oral water flows manage to deposit food at the esophagus entrance remains unknown. In theory, the posteriorly moving water must, at some point, curve laterally and/or ventrally to exit through the gill slits. Such flows would eventually carry food away from the esophagus instead of toward it. This apparent paradox calls for a filtration mechanism to deviate food from the suction-feeding streamlines. To study this gap in our fundamental understanding of how fishes feed, we developed and applied a new technique to quantify three-dimensional patterns of intra-oral water flows in vivo. We combined stereoscopic high-speed x-ray videos to quantify skeletal motion (XROMM) with 3D x-ray particle tracking (XPT) of neutrally buoyant spheres of 1.4 mm in diameter. We show, for carp (Cyprinus carpio) and tilapia (Oreochromis niloticus), that water tracers displayed higher curvatures than food tracers, indicating an inertia-driven filtration. In addition, tilapia also exhibited a 'central jet' flow pattern, which aids in quickly carrying food to the pharyngeal jaw region. When the food was trapped at the branchial basket, it was resuspended and carried more centrally by periodical bidirectional waterflows, synchronized with head-bone motions. By providing a complete picture of the suction-feeding process and revealing fundamental differences in food transport mechanisms among species, this novel technique opens a new area of investigation to fully understand how most aquatic vertebrates feed.
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Affiliation(s)
- Pauline Provini
- Département Adaptations du Vivant, UMR 7179 CNRS, MNHN, Paris, France
| | - Alexandre Brunet
- Département Adaptations du Vivant, UMR 7179 CNRS, MNHN, Paris, France
| | - Andréa Filippo
- Département Adaptations du Vivant, UMR 7179 CNRS, MNHN, Paris, France
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4
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Gavrilchuk K, Lesage V, Fortune SME, Trites AW, Plourde S. Foraging habitat of North Atlantic right whales has declined in the Gulf of St. Lawrence, Canada, and may be insufficient for successful reproduction. ENDANGER SPECIES RES 2021. [DOI: 10.3354/esr01097] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Climate-induced changes in calanoid copepod (Calanus spp.) availability in traditional feeding areas might explain why a large proportion of the North Atlantic right whale Eubalaena glacialis population has fed in the Gulf of St. Lawrence (Canada) in recent years. However, little is known about the distribution of copepods in the gulf, and whether their abundance is sufficient to energetically sustain right whales. We used a mechanistic modelling approach to predict areas within the gulf that have foraging potential for adult female right whales, based on the annual energetic needs of resting, pregnant and lactating females, and their theoretical prey density requirements. We identified suitable foraging areas for right whales by coupling a foraging bioenergetics model with a 12 yr data set (2006-2017) describing the abundance and 3-dimensional distribution of late-stage Calanus spp. in the gulf. Prey densities in the southern gulf (from Shediac Valley to the Magdalen Islands) supported all 3 reproductive states in most (≥6) years. However, foraging habitat became progressively sparse in the southern gulf over time, with noticeably less suitable habitat available after 2014. Few other potentially suitable foraging areas were identified elsewhere in the gulf. Overall, the availability of foraging habitat in the gulf varied considerably between years, and was higher for resting females than for pregnant and lactating females. Our findings are consistent with the recent low calving rates, and indicate that prey biomass in the Gulf of St. Lawrence may be insufficient in most years to support successful reproduction of North Atlantic right whales.
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Affiliation(s)
- K Gavrilchuk
- Fisheries and Oceans Canada, Mont-Joli, QC G5H 3Z4, Canada
| | - V Lesage
- Fisheries and Oceans Canada, Mont-Joli, QC G5H 3Z4, Canada
| | - SME Fortune
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - AW Trites
- Marine Mammal Research Unit, Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - S Plourde
- Fisheries and Oceans Canada, Mont-Joli, QC G5H 3Z4, Canada
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5
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Zhu Y, Hu D, Yang G. Theoretical analysis of the hydrodynamic filtering system in the balaenid whales suspension feeding. BIOINSPIRATION & BIOMIMETICS 2020; 16:026006. [PMID: 33105121 DOI: 10.1088/1748-3190/abc493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 10/26/2020] [Indexed: 06/11/2023]
Abstract
Balaenid whales are giant filter feeders that feed on the dense aggregations of prey. Through their unique oral filters, they can effectively filter water out and leave prey in their mouths. In this study, a theoretical model is established to analyze the hydrodynamic filtering system in the balaenid whales suspension feeding. First, the appropriate velocity profiles in the anteroposterior and mediolateral directions are adopted to approximate the flow field in the anteroposterior channel along the tongue (APT channel). Then, a four-stage Runge-Kutta method is used to calculate the particle trajectories and predict the corresponding filter cake profile by solving the particle motion equations. Finally, the effects of three crucial parameters, i.e. the APT channel widthDT, the fringe layer permeabilityK, and the food particle diameterdp, are discussed. The results show that the particle trajectories consist of a series of backward-outward arcs and the food particles tend to accumulate in the posterior region of the oral cavity. The growing parabolic filter cake profiles are formed except for the case of extremely low permeability. A smallDTand largeKmake the tendency of particle posterior aggregation obviously. So squeezing the tongue and having larger fringe layer permeability are both conducive to the swallowing process. But the change indphas less influence on this tendency. The proposed theoretical analysis method is a fast and low-cost calculation method. The study on the balaenid whales' filter feeding biomechanics and hydrodynamics is helpful to guide the design of the high-efficiency bionic filters.
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Affiliation(s)
- Yawei Zhu
- State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha 410082, People's Republic of China
- Key Laboratory of Advanced Design and Simulation Techniques for Special Equipments, Ministry of Education, Hunan University, Changsha 410082, People's Republic of China
| | - Dean Hu
- State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha 410082, People's Republic of China
- Key Laboratory of Advanced Design and Simulation Techniques for Special Equipments, Ministry of Education, Hunan University, Changsha 410082, People's Republic of China
| | - Gang Yang
- State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha 410082, People's Republic of China
- Key Laboratory of Advanced Design and Simulation Techniques for Special Equipments, Ministry of Education, Hunan University, Changsha 410082, People's Republic of China
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6
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Cade DE, Levenson JJ, Cooper R, de la Parra R, Webb DH, Dove ADM. Whale sharks increase swimming effort while filter feeding, but appear to maintain high foraging efficiencies. J Exp Biol 2020; 223:jeb224402. [PMID: 32366692 DOI: 10.1242/jeb.224402] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 04/25/2020] [Indexed: 08/26/2023]
Abstract
Whale sharks (Rhincodon typus) - the largest extant fish species - reside in tropical environments, making them an exception to the general rule that animal size increases with latitude. How this largest fish thrives in tropical environments that promote high metabolism but support less robust zooplankton communities has not been sufficiently explained. We used open-source inertial measurement units (IMU) to log 397 h of whale shark behavior in Yucatán, Mexico, at a site of both active feeding and intense wildlife tourism. Here we show that the strategies employed by whale sharks to compensate for the increased drag of an open mouth are similar to ram feeders five orders of magnitude smaller and one order of magnitude larger. Presumed feeding constituted 20% of the total time budget of four sharks, with individual feeding bouts lasting up to 11 consecutive hours. Compared with normal, sub-surface swimming, three sharks increased their stroke rate and amplitude while surface feeding, while one shark that fed at depth did not demonstrate a greatly increased energetic cost. Additionally, based on time-depth budgets, we estimate that aerial surveys of shark populations should consider including a correction factor of 3 to account for the proportion of daylight hours that sharks are not visible at the surface. With foraging bouts generally lasting several hours, interruptions to foraging during critical feeding periods may represent substantial energetic costs to these endangered species, and this study presents baseline data from which management decisions affecting tourist interactions with whale sharks may be made.
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Affiliation(s)
- David E Cade
- Institute of Marine Science, University of California, Santa Cruz, 115 McAllister Way, Santa Cruz, CA 95060, USA
- Hopkins Marine Station, Stanford University, 120 Ocean View Blvd, Pacific Grove, CA 93950, USA
| | - J Jacob Levenson
- US Department of Interior, Bureau of Ocean Energy Management, 1849 C Street, NW, Washington, DC 20240, USA
| | - Robert Cooper
- Oceans Forward, 17 Hamilton St, Plymouth, MA 02360, USA
| | | | - D Harry Webb
- Research and Conservation Department, Georgia Aquarium, 225 Baker St, Atlanta, GA 30313, USA
| | - Alistair D M Dove
- Research and Conservation Department, Georgia Aquarium, 225 Baker St, Atlanta, GA 30313, USA
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7
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Werth AJ, Sformo TL, Lysiak NS, Rita D, George JC. Baleen turnover and gut transit in mysticete whales and its environmental implications. Polar Biol 2020. [DOI: 10.1007/s00300-020-02673-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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8
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Goldbogen JA, Cade DE, Wisniewska DM, Potvin J, Segre PS, Savoca MS, Hazen EL, Czapanskiy MF, Kahane-Rapport SR, DeRuiter SL, Gero S, Tønnesen P, Gough WT, Hanson MB, Holt MM, Jensen FH, Simon M, Stimpert AK, Arranz P, Johnston DW, Nowacek DP, Parks SE, Visser F, Friedlaender AS, Tyack PL, Madsen PT, Pyenson ND. Why whales are big but not bigger: Physiological drivers and ecological limits in the age of ocean giants. Science 2020; 366:1367-1372. [PMID: 31831666 DOI: 10.1126/science.aax9044] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 10/31/2019] [Indexed: 12/27/2022]
Abstract
The largest animals are marine filter feeders, but the underlying mechanism of their large size remains unexplained. We measured feeding performance and prey quality to demonstrate how whale gigantism is driven by the interplay of prey abundance and harvesting mechanisms that increase prey capture rates and energy intake. The foraging efficiency of toothed whales that feed on single prey is constrained by the abundance of large prey, whereas filter-feeding baleen whales seasonally exploit vast swarms of small prey at high efficiencies. Given temporally and spatially aggregated prey, filter feeding provides an evolutionary pathway to extremes in body size that are not available to lineages that must feed on one prey at a time. Maximum size in filter feeders is likely constrained by prey availability across space and time.
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Affiliation(s)
- J A Goldbogen
- Hopkins Marine Station, Department of Biology, Stanford University, Pacific Grove, CA, USA.
| | - D E Cade
- Hopkins Marine Station, Department of Biology, Stanford University, Pacific Grove, CA, USA
| | - D M Wisniewska
- Hopkins Marine Station, Department of Biology, Stanford University, Pacific Grove, CA, USA
| | - J Potvin
- Department of Physics, Saint Louis University, St. Louis, MO, USA
| | - P S Segre
- Hopkins Marine Station, Department of Biology, Stanford University, Pacific Grove, CA, USA
| | - M S Savoca
- Hopkins Marine Station, Department of Biology, Stanford University, Pacific Grove, CA, USA
| | - E L Hazen
- Hopkins Marine Station, Department of Biology, Stanford University, Pacific Grove, CA, USA.,Environmental Research Division, National Oceanic and Atmospheric Administration, Southwest Fisheries Science Center, Monterey, CA, USA.,Institute of Marine Sciences, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - M F Czapanskiy
- Hopkins Marine Station, Department of Biology, Stanford University, Pacific Grove, CA, USA
| | - S R Kahane-Rapport
- Hopkins Marine Station, Department of Biology, Stanford University, Pacific Grove, CA, USA
| | - S L DeRuiter
- Mathematics and Statistics Department, Calvin University, Grand Rapids, MI, USA
| | - S Gero
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - P Tønnesen
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - W T Gough
- Hopkins Marine Station, Department of Biology, Stanford University, Pacific Grove, CA, USA
| | - M B Hanson
- Conservation Biology Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, WA, USA
| | - M M Holt
- Conservation Biology Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, WA, USA
| | - F H Jensen
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - M Simon
- Greenland Climate Research Centre, Greenland Institute of Natural Resources, Nuuk, Greenland
| | - A K Stimpert
- Moss Landing Marine Laboratories, Moss Landing, CA, USA
| | - P Arranz
- Biodiversity, Marine Ecology and Conservation Group, Department of Animal Biology, University of La Laguna, La Laguna, Spain
| | - D W Johnston
- Nicholas School of the Environment, Duke University Marine Laboratory, Beaufort, NC, USA
| | - D P Nowacek
- Pratt School of Engineering, Duke University, Durham, NC, USA
| | - S E Parks
- Department of Biology, Syracuse University, Syracuse, NY, USA
| | - F Visser
- Department of Freshwater and Marine Ecology, IBED, University of Amsterdam, Amsterdam, Netherlands.,Department of Coastal Systems, NIOZ and Utrecht University, Utrecht, Netherlands.,Kelp Marine Research, Hoorn, Netherlands
| | - A S Friedlaender
- Institute of Marine Sciences, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - P L Tyack
- Sea Mammal Research Unit, School of Biology, Scottish Oceans Institute, University of St Andrews, St Andrews, UK
| | - P T Madsen
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark.,Aarhus Institute of Advanced Studies, Aarhus University, DK-8000 Aarhus C, Denmark
| | - N D Pyenson
- Department of Paleobiology, National Museum of Natural History, Washington, DC, USA.,Department of Paleontology and Geology, Burke Museum of Natural History and Culture, Seattle, WA, USA
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9
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Zhu Y, Yang G, Zhuang C, Li C, Hu D. Oral cavity flow distribution and pressure drop in balaenid whales feeding: a theoretical analysis. BIOINSPIRATION & BIOMIMETICS 2020; 15:036004. [PMID: 31978919 DOI: 10.1088/1748-3190/ab6fb8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Balaenid whales, as continuous ram filter feeders, can efficiently separate prey from water by baleen. The feeding process of balaenid whales is extremely complex, in which the flow distribution and pressure drop in the oral cavity play a significant role. In this paper, a theoretical model coupled with oral cavity velocity and pressure in balaenid whales is established based on mass conservation, momentum conservation and pressure drop equations, considering both the inertial and the friction terms. A discrete method with section-by-section calculation is adopted to solve the theoretical model. The effects of four crucial parameters, i.e. the ratio of filtration area to inlet area (S), the Reynolds number of entrance (Re in ), the ratio of thickness to permeability of the porous media formed by the fringe layer (ϕ) and the width ratio of the anteroposterior canal within the mouth along the tongue (APT channel) to that along the lip (APL channel) (H) are discussed. The results show that, for a given case, the flow distribution and the pressure drop both show increasing trends with the flow direction. For different cases, when S is small, Re in is small and ϕ is large, a good flow pattern emerges with a smoother flow speed near the oropharynx, better drainage, better shunting and filtration, and higher energy efficiency. However, for smaller values of H, some energy efficiency is sacrificed to achieve additional average transverse flow in order to produce better shunting and filtration. The research in this paper provides a reference for the design of high-efficiency bionic filters.
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Affiliation(s)
- Yawei Zhu
- State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha 410082, People's Republic of China. Key Laboratory of Advanced Design and Simulation Techniques for Special Equipments, Ministry of Education, Hunan University, Changsha 410082, People's Republic of China
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10
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Abstract
The largest animals are baleen filter feeders that exploit large aggregations of small-bodied plankton. Although this feeding mechanism has evolved multiple times in marine vertebrates, rorqual whales exhibit a distinct lunge filter feeding mode that requires extreme physiological adaptations-most of which remain poorly understood. Here, we review the biomechanics of the lunge feeding mechanism in rorqual whales that underlies their extraordinary foraging performance and gigantic body size.
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Affiliation(s)
- Robert E Shadwick
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jean Potvin
- Department of Physics, Saint Louis University, St. Louis, Missouri
| | - Jeremy A Goldbogen
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, California
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11
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Hoop JM, Nousek‐McGregor AE, Nowacek DP, Parks SE, Tyack P, Madsen PT. Foraging rates of ram‐filtering North Atlantic right whales. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13357] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | - Douglas P. Nowacek
- Nicholas School of the Environment & Pratt School of Engineering Duke University Beaufort North California
| | - Susan E. Parks
- Biology Department Syracuse University Syracuse New York
| | - Peter Tyack
- Sea Mammal Research Unit, Scottish Oceans Institute University of St Andrews St Andrews UK
| | - Peter Teglberg Madsen
- Department of Bioscience Aarhus University Aarhus Denmark
- Aarhus Institute of Advanced Studies Aarhus University Aarhus Denmark
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12
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Werth AJ, Rita D, Rosario MV, Moore MJ, Sformo TL. How do baleen whales stow their filter? A comparative biomechanical analysis of baleen bending. ACTA ACUST UNITED AC 2018; 221:jeb.189233. [PMID: 30337355 DOI: 10.1242/jeb.189233] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 10/11/2018] [Indexed: 11/20/2022]
Abstract
Bowhead and right whale (balaenid) baleen filtering plates, longer in vertical dimension (≥3-4 m) than the closed mouth, presumably bend during gape closure. This has not been observed in live whales, even with scrutiny of video-recorded feeding sequences. To determine what happens to the baleen during gape closure, we conducted an integrative, multifactorial study including materials testing, functional (flow tank and kinematic) testing and histological examination. We measured baleen bending properties along the dorsoventral length of plates and anteroposterior location within a rack of plates via mechanical (axial bending, composite flexure, compression and tension) tests of hydrated and air-dried tissue samples from balaenid and other whale baleen. Balaenid baleen is remarkably strong yet pliable, with ductile fringes, and low stiffness and high elasticity when wet; it likely bends in the closed mouth when not used for filtration. Calculation of flexural modulus from stress/strain experiments shows that the balaenid baleen is slightly more flexible where it emerges from the gums and at its ventral terminus, but kinematic analysis indicates plates bend evenly along their whole length. Fin and humpback whale baleen has similar material properties but less flexibility, with no dorsoventral variation. The internal horn tubes have greater external and hollow luminal diameter but lower density in the lateral relative to medial baleen of bowhead and fin whales, suggesting a greater capacity for lateral bending. Baleen bending has major consequences not only for feeding morphology and energetics but also for conservation given that entanglement in fishing gear is a leading cause of whale mortality.
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Affiliation(s)
- Alexander J Werth
- Department of Biology, Hampden-Sydney College, Hampden-Sydney, VA 23943, USA
| | - Diego Rita
- Department of Evolutionary Biology, Ecology, and Environmental Science, University of Barcelona, 08028 Barcelona, Spain
| | - Michael V Rosario
- Department of Ecology & Evolutionary Biology, Brown University, Providence, RI 02912, USA
| | - Michael J Moore
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Todd L Sformo
- Department of Wildlife Management, North Slope Borough, Barrow, AK 99723, USA.,Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
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13
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Kahane‐Rapport SR, Goldbogen JA. Allometric scaling of morphology and engulfment capacity in rorqual whales. J Morphol 2018; 279:1256-1268. [DOI: 10.1002/jmor.20846] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 05/16/2018] [Accepted: 05/17/2018] [Indexed: 11/10/2022]
Affiliation(s)
- Shirel R. Kahane‐Rapport
- Department of Biology, Hopkins Marine Station Stanford University 120 Ocean View Blvd, Pacific Grove California
| | - Jeremy A. Goldbogen
- Department of Biology, Hopkins Marine Station Stanford University 120 Ocean View Blvd, Pacific Grove California
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14
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Werth AJ, Potvin J, Shadwick RE, Jensen MM, Cade DE, Goldbogen JA. Filtration area scaling and evolution in mysticetes: trophic niche partitioning and the curious cases of sei and pygmy right whales. Biol J Linn Soc Lond 2018. [DOI: 10.1093/biolinnean/bly121] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Alexander J Werth
- Department of Biology, Hampden-Sydney College, Hampden-Sydney, VA, USA
| | - Jean Potvin
- Department of Physics, Saint Louis University, St. Louis, MO, USA
| | - Robert E Shadwick
- Department of Zoology, University of British Columbia, Vancouver, B.C., Canada
| | - Megan M Jensen
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA
| | - David E Cade
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA
| | - Jeremy A Goldbogen
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA
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Jensen MM, Saladrigas AH, Goldbogen JA. Comparative Three-Dimensional Morphology of Baleen: Cross-Sectional Profiles and Volume Measurements Using CT Images. Anat Rec (Hoboken) 2018; 300:1942-1952. [PMID: 28971628 PMCID: PMC5656919 DOI: 10.1002/ar.23648] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Revised: 06/14/2017] [Accepted: 06/17/2017] [Indexed: 12/29/2022]
Abstract
Baleen whales are obligate filter feeders, straining prey‐laden seawater through racks of keratinized baleen plates. Despite the importance of baleen to the ecology and natural history of these animals, relatively little work has been done on baleen morphology, particularly with regard to the three‐dimensional morphology and structure of baleen. We used computed tomography (CT) scanning to take 3D images of six baleen specimens representing five species, including three complete racks. With these images, we described the three‐dimensional shape of the baleen plates using cross‐sectional profiles from within the gum tissue to the tip of the plates. We also measured the percentage of each specimen that was composed of either keratinized plate material or was void space between baleen plates, and thus available for seawater flow. Baleen plates have a complex three‐dimensional structure with curvature that varies across the anterior‐posterior, proximal‐distal, and medial‐lateral (lingual‐labial) axes. These curvatures also vary with location along the baleen rack, and between species. Cross‐sectional profiles resemble backwards‐facing airfoils, and some specimens display S‐shaped, or reflexed, camber. Within a baleen specimen, the intra‐baleen void volume correlates with the average bristle diameter for a species, suggesting that essentially, thinner plates (with more space between them for flow) have thinner bristles. Both plate curvature and the relative proportions of plate and void volumes are likely to have implications for the mechanics of mysticete filtration, and future studies are needed to determine the particular functions of these morphological characters. Anat Rec, 300:1942–1952, 2017. © 2017 The Authors The Anatomical Record published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists
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Affiliation(s)
- Megan M Jensen
- Hopkins Marine Station of Stanford University, Pacific Grove, California, 93950
| | - Amalia H Saladrigas
- Hopkins Marine Station of Stanford University, Pacific Grove, California, 93950
| | - Jeremy A Goldbogen
- Hopkins Marine Station of Stanford University, Pacific Grove, California, 93950
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