Scaling of swim speed and stroke frequency in geometrically similar penguins: they swim optimally to minimize cost of transport

Sato, Katsufumi; Shiomi, Kozue; Watanabe, Yuki; Watanuki, Yutaka; Takahashi, Akinori; Ponganis, Paul J.

doi:10.1098/rspb.2009.1515

Cited by 65 publications

(128 citation statements)

References 28 publications

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“…By contrast, during ascent, negatively buoyant seals employed active stroking (high ascent strokes-per-metre) more than prolonged gliding (figure 2). Seals appeared to adjust stroking effort depending on buoyancy changes to maintain a narrow range of ascent swim speeds (figure 2; electronic supplementary material, figure S4), which might reflect a swim speed that minimizes swimming costs in the buoyancy-hindered direction [25,45,46].…”

Section: Discussion (A) Buoyancy Determines Locomotor Costs Of Swimmingmentioning

confidence: 99%

The foraging benefits of being fat in a highly migratory marine mammal

et al. 2014

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Foraging theory predicts that breath-hold divers adjust the time spent foraging at depth relative to the energetic cost of swimming, which varies with buoyancy (body density). However, the buoyancy of diving animals varies as a function of their body condition, and the effects of these changes on swimming costs and foraging behaviour have been poorly examined. A novel animalborne accelerometer was developed that recorded the number of flipper strokes, which allowed us to monitor the number of strokes per metre swam (hereafter, referred to as strokes-per-metre) by female northern elephant seals over their months-long, oceanic foraging migrations. As negatively buoyant seals increased their fat stores and buoyancy, the strokes-per-metre increased slightly in the buoyancy-aided direction (descending), but decreased significantly in the buoyancy-hindered direction (ascending), with associated changes in swim speed and gliding duration. Overall, the round-trip strokes-per-metre decreased and reached a minimum value when seals achieved neutral buoyancy. Consistent with foraging theory, seals stayed longer at foraging depths when their round-trip strokes-per-metre was less. Therefore, neutrally buoyant divers gained an energetic advantage via reduced swimming costs, which resulted in an increase in time spent foraging at depth, suggesting a foraging benefit of being fat.

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Section: Discussion (A) Buoyancy Determines Locomotor Costs Of Swimmingmentioning

confidence: 99%

The foraging benefits of being fat in a highly migratory marine mammal

et al. 2014

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“…If we replace the spring constant with muscle stiffness, we would expect the frequency of oscillatory movements in animals to increase with increasing muscle stiffness and decrease with increasing body mass. Much work on oscillatory movement has shown that body size is often correlated with frequency (Heglund and Taylor, 1988;Young et al, 1992;Lindstedt and Schaeffer, 2002 and references therein; Hurlbert et al, 2008;Sato et al, 2010;Dickerson et al, 2012). The frequency of muscle activation during shivering thermogenesis also seems to be correlated with body mass (Spaan and Klussmann, 1970).…”

Section: Introductionmentioning

confidence: 99%

Shiver me titin! Elucidating titin's role in shivering thermogenesis

Taylor-Burt

Monroy

Pace

et al. 2015

Journal of Experimental Biology

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Shivering frequency scales predictably with body mass and is 10 times higher in a mouse than a moose. The link between shivering frequency and body mass may lie in the tuning of muscle elastic properties. Titin functions as a muscle 'spring', so shivering frequency may be linked to titin's structure. The muscular dystrophy with myositis (mdm) mouse is characterized by a deletion in titin's N2A region. Mice that are homozygous for the mdm mutation have a lower body mass, stiffer gait and reduced lifespan compared with their wild-type and heterozygous siblings. We characterized thermoregulation in these mice by measuring metabolic rate and tremor frequency during shivering. Mutants were heterothermic at ambient temperatures of 20-37°C while wild-type and heterozygous mice were homeothermic. Metabolic rate increased at smaller temperature differentials (i.e. the difference between body and ambient temperatures) in mutants than in nonmutants. The difference between observed tremor frequencies and shivering frequencies predicted by body mass was significantly larger for mutant mice than for wild-type or heterozygous mice, even after accounting for differences in body temperature. Together, the heterothermy in mutants, the increase in metabolic rate at low temperature differentials and the decreased tremor frequency demonstrate the thermoregulatory challenges faced by mice with the mdm mutation. Oscillatory frequency is proportional to the square root of stiffness, and we observed that mutants had lower active muscle stiffness in vitro. The lower tremor frequencies in mutants are consistent with reduced active muscle stiffness and suggest that titin affects the tuning of shivering frequency.

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“…For both pelagic marine animals and AUVs it is common to transit at or near U opt minimising the COT and in the case of AUVs maximising the range, Sato et al (2010). Figure 9 compares the optimum cost of transport, COT opt , for various marine animals and AUVs.…”

Section: Optimum Cost Of Transportmentioning

confidence: 99%

Nature in engineering for monitoring the oceans: comparison of the energetic costs of marine animals and AUVs

Phillips

Haroutunian

Man

et al. 2012

Further Advances in Unmanned Marine Vehicles

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The range of physiological adaptations possessed by marine animals allowing them to successfully operate in the marine environment is a plentiful source of inspiration for the designers of Autonomous Underwater Vehicles. This chapter compares the total energetic cost of straight line swimming for both marine animals and AUVs, using cost of transport (COT) as a comparative metric. COT is a normalised measure of the energetic cost of transporting the animal's or vehicle's mass over a unit distance. It includes non propulsion power requirements as well as considering the energy lost by actuators and mechanical couplings and energy lost in the wake. Comparisons presented in this chapter show that marine animals typically have higher optimum COT than engineered systems of equivalent size. However parallels may be drawn, for example, to increase range both marine animals and AUVs appear to favour reducing non-propulsion power costs and travelling slowly to ensure operating at the minimum COT.

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Scaling of swim speed and stroke frequency in geometrically similar penguins: they swim optimally to minimize cost of transport

Cited by 65 publications

References 28 publications

The foraging benefits of being fat in a highly migratory marine mammal

The foraging benefits of being fat in a highly migratory marine mammal

Shiver me titin! Elucidating titin's role in shivering thermogenesis

Nature in engineering for monitoring the oceans: comparison of the energetic costs of marine animals and AUVs

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