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1. Whelk egg case precursor proteins are stockpiled in the nidamental gland of a gravid female whelk and assembled post-fertilization into an impervious protective coating for the egg. 2. Egg case maturation is rapid and involves extensive chemical crosslinking. 3. Egg case material is quasi-elastic and completely reversible in tension, but relies primarily on nonentropic forces. 4. Fibers with the mechanical properties of whelk egg case can be electrospun from protein precursors.

The goal of this project was to characterize basic biochemical and mechanical properties of egg capsules from several species of whelk snails, including the channeled whelk snail, Busycon canaliculatum, native to the East Coast, and the Kellet’s whelk snail, Kelletia kelletii, native to the West Coast. Tests focused on quantifying the material’s response to being stretched. Of particular interest was measuring the amount of energy dissipated as the material returns to its original shape. Other tests involved stretching and relaxing the material repeatedly.

Whales are important model systems for understanding the physiological and ecological consequences of extreme body size. However, whales are also some of the most difficult animals to study because their large size precludes experimental studies under controlled conditions. Here we review a wide range of morphological studies that enable greater inference of physiological processes. In particular, we focus on baleen whales that exhibit extensive diving and foraging adaptations. Using morphological data, we (i) explore the biomechanics and sensory physiology of lunge-feeding rorqual whales (Balaenopteridae), (ii) determine the effects of scale and diving pressures on the circulatory physiology of fin whales (Balaenoptera physalus (L., 1758)), and (iii) better understand the adaptations of the cetacean respiratory system that facilitate a fully aquatic life history. These studies underscore the value of understanding functional morphology in animals that cannot be studied using traditional laboratory techniques. Key words: whales, morphology, physiology, diving, biomechanics, bioenergetics, feeding. Les baleines constituent d'importants systemes modeles pour comprendre les consequences physiologiques et ecologiques d'une taille extreme du corps. Les baleines figurent toutefois parmi les animaux les plus difficiles a etudier parce que leur grande taille fait en sorte qu'il est impossible de mener des etudes experimentales dans des conditions controlees. Nous passons en revue un vaste eventail d'etudes morphologiques qui permettent de meilleures inferences concernant les processus physiologiques. Nous nous penchons plus particulierement sur les mysticetes qui presentent d'importantes adaptations en matiere de plongee et d'approvisionnement. A la lumiere de donnees morphologiques, nous (i) explorons la biomecanique et la physiologie sensorielle de rorquals qui se nourrissent par engouffrement (balenopterides), (ii) determinons les effets d'echelle et des pressions de plongee sur la physiologie de la circulation de rorquals communs (Balaenoptera physalus (L., 1758)) et (iii) etablissons une comprehension amelioree des adaptations du systeme respiratoire des cetaces qui facilitent un cycle biologique entierement aquatique. Ces etudes soulignent l'importance de comprendre la morphologie fonctionnelle d'animaux qui ne peuvent etre etudies par des techniques de laboratoire classiques. [Traduit par la Redaction] Mots-cles : baleines, morphologie, physiologie, plongee, biomecaniques, bioenergetique, alimentation., Introduction Body size is one the most important characteristics that influence physiological processes and ecosystem function (Schmidt-Nielsen 1984). At the upper extreme of body mass, there is a tremendous dearth [...]

Thunniform propulsion is considered a case study in convergent evolution. Independently derived at least four times, it is characterized by uniquely high lift-based thrust and efficient performance. As such, it has been the focus of studies from biologists, engineers, and physicists. Unfortunately, direct physical measurements of this phenomenon are difficult to obtain. Therefore, the majority of research so far has consisted of theoretical modeling or experimental testing with models of low biofidelity. We created a test apparatus that would more accurately mimic thunniform propulsion as seen in the skipjack tuna (Katsuwonus pelamis (L., 1758)). Motion parameters and swimming speeds, as well as caudal fin size, shape, and material properties, were all taken into account and closely matched with in vivo measurements. Instantaneous lateral and in-flow forces were measured in tests over a range of motion regimes. Overall, general motion parameter requirements for thrust generation were determined and quantified. Thrust production, of up to 0.42 N (per whole caudal fin) with a coefficient of thrust of approximately 0.2, were in line with estimates of whole-body drag. Propulsive efficiency estimates were low (≤ 35%) compared with estimates in the literature of up to 90%. Quasi-static analysis was also conducted and shown to underpredict measured thrust values by up to 50%. Key words: tuna, thunniform, swimming, thrust, hydrofoil. Le groupe de propulsion thunniform est considere comme un exemple typique devolution convergente. Derive independamment au moins quatre fois, le groupe se caracterise par sa capacite a generer une forte portance, source de la poussee, et sa haute performance en efficacite. En tant que tel, ce groupe a fait l'objet d'un grand nombre d'etudes de biologistes, d'ingenieurs et de physiciens. Malheureusement, une mesure physique directement sur l'animal de ce phenomene est difficile a obtenir. Par consequent, la majorite de la recherche sur le sujet jusqu'a present a consiste en une modelisation theorique ou des essais experimentaux a faible bio-fidelite. Le but de cette etude etait de creer un appareil d'essai qui serait plus precisement imiter le groupe de propulsion thunniform, represente dans cette etude par le thon listao (Katsuwonus pelamis (L., 1758)). Des facteurs tels que les parametres de mouvement et la vitesse de natation ainsi que la taille de la nageoire caudale, la forme et les proprietes des materiaux ont tous ete pris en compte et correspondent avec les mesures in vivo. Des mesures instantanees de forces laterales et longitudinales ont ete prises tout au long des l'essais. Dans l'ensemble, les exigences generales des differents parametres de mouvement pour la production de poussee ont ete determinees et quantifiees. La production de poussee, pouvant aller jusqu'a 0,42 N (pour la queue entiere) avec un coefficient de poussee d'environ 0,2, a ete jugee conforme avec l'estimation de trainee totale pour chaque conditions testees. Les mesures d'efficacite de propulsion cependant, ont ete juges basses (≤ 35 %) par rapport aux estimations dans la litterature d'un maximum de 90 %. Une analyse quasi-statique a egalement ete menee et se revela de sous-estimer les vraies valeurs de poussee par jusqu'a 50 %. Mots-cles: thon, thunniform, nage, poussee, aile portante immergee., Introduction The evolution of thrust generation via oscillating and pitching lift-generating surfaces (airfoils and hydrofoils) has emerged as a repeated theme throughout the animal kingdom, appearing in various groups of [...]

Top ocean predators have evolved multiple solutions to the challenges of feeding in the water (1-3). At the largest scale, rorqual whales (Balaenopteridae) engulf and filter prey-laden water by lunge [...]

Author(s): Diego Bernal (corresponding author) [1, 2]; Jeanine M. Donley [3]; Robert E. Shadwick (corresponding author) [2, 5]; Douglas A. Syme [4] Effects of temperature on muscle contraction and powering [...]

Author(s): Jeanine M. Donley (corresponding author) [1]; Chugey A. Sepulveda [1]; Peter Konstantinidis [2]; Sven Gemballa [2]; Robert E. Shadwick [1] The evolution of 'thunniform' body shapes in several different [...]

Characterization of the mechanical properties of the major arteries of the fin whale, Balaenoptera physalus, shows that the aortic arch of the whale is 2.5 times larger than the other thoracic aorta and contains more than 90% of arterial capacitance to serve as a compliant windkessel. The remaining section of the aorta is rigid and does not contribute much to in vivo arterial capacitance. The compliant windkessel role of the aortic arch helps decrease inflow pulsativity to the descending thoracic aorta.

An analysis of hindlimb muscle-tendon units in 35 quadrupedal species reveals that the springlike tendons of large animals may store larger amounts of elastic strain energy in comparison with the tendons of smaller mammals. This may be necessary because of stronger muscles that are capable of causing greater tendon stresses. Elastic energy storage in tendons is correlated with increasing positive allometry but exhibits isometric nature in digital extensors.

Experiments conducted on 18 species of quadrupedal mammals reveal that digital flexor and ankle extensor tendons have similar elastic modulus and hysteresis properties as that of digital sensors. This similarity indicates an identical capacity for storing elastic energy. Body mass or species does not alter the material properties of tendons. Digital extensor properties resemble those of digital flexors.