IS WALKING COSTLY FOR ANURANS? THE ENERGETIC COST OF WALKING IN THE NORTHERN TOAD BUFO BOREAS HALOPHILUS

1994 ◽  
Vol 197 (1) ◽  
pp. 165-178
Author(s):  
B Walton ◽  
C Peterson ◽  
A Bennett
Keyword(s):  
Oxygen Consumption ◽  
Body Mass ◽  
Minimum Cost ◽  
Aerobic Metabolism ◽  
Energetic Cost ◽  
Cost Of Transport ◽  
Bufo Boreas ◽  
Steady State Rate ◽  
Rate Of Oxygen Consumption ◽  
Locomotor Energetics

Locomotor mode and the maximal capacity for aerobic metabolism are thought to be co-adapted in anuran amphibians. Species that rely heavily on walking often have high capacities for aerobic metabolism relative to species that rely primarily on saltation. We tested the hypothesis of co-adaptation of gait and aerobic metabolism by investigating the locomotor energetics of Bufo boreas halophilus, a toad that walks, but does not hop. Rates of oxygen consumption during locomotion were measured in an enclosed variable-speed treadmill. The steady-state rate of oxygen consumption (V(dot)O2ss) increased linearly within a range of sustainable speeds [V(dot)O2ss (ml O2 g-1 h-1) = 0.93 x speed (km h-1) + 0.28]. The minimum cost of transport, Cmin (the slope of this relationship), varied significantly among individual toads. When expressed in units of oxygen consumed per distance travelled (ml O2 km-1), Cmin scaled isometrically with body mass: Cmin = 0.69mass1.07. Consequently, mass-specific Cmin (ml O2 g-1 km-1) was uncorrelated with body mass. Variation in Cmin was also unrelated to experimental temperature. Mass-specific Cmin estimates were similar to previous allometric predictions for terrestrial animals of similar size, which contrasts with previous findings for another toad species. Maximum rates of oxygen consumption measured in closed, rotating respirometers were significantly higher than the maximum rates achieved on the treadmill, but lower than those measured previously in other Bufo species. Our results indicate that walking is not necessarily a costly gait for toads and that high maximum rates of oxygen consumption are not associated with reliance on walking within the genus Bufo.

Efficiency of uphill locomotion in nocturnal and diurnal lizards

1996 ◽  
Vol 199 (3) ◽  
pp. 587-592 ◽  
Author(s):  
C Farley ◽  
M Emshwiller
Keyword(s):  
Body Mass ◽  
Low Cost ◽  
Minimum Cost ◽  
Mechanical Work ◽  
Energetic Cost ◽  
Cost Of Transport ◽  
Unit Distance ◽  
Cost Of Locomotion ◽  
Average Body Mass ◽  
Average Body

Nocturnal geckos can walk on level ground more economically than diurnal lizards. One hypothesis for why nocturnal geckos have a low cost of locomotion is that they can perform mechanical work during locomotion more efficiently than other lizards. To test this hypothesis, we compared the efficiency of the nocturnal gecko Coleonyx variegatus (average body mass 4.2 g) and the diurnal skink Eumeces skiltonianus (average body mass 4.8 g) when they performed vertical work during uphill locomotion. We measured the rate of oxygen consumption when each species walked on the level and up a 50 slope over a range of speeds. For Coleonyx variegatus, the energetic cost of traveling a unit distance (the minimum cost of transport, Cmin) increased from 1.5 to 2.7 ml O2 kg-1 m-1 between level and uphill locomotion. For Eumeces skiltonianus, Cmin increased from 2.5 to 4.7 ml O2 kg-1 m-1 between level and uphill locomotion. By taking the difference between Cmin for level and uphill locomotion, we found that the efficiency of performing vertical work during locomotion was 37 % for Coleonyx variegatus and 19 % for Eumeces skiltonianus. The similarity between the 1.9-fold difference in vertical efficiency and the 1.7-fold difference in the cost of transport on level ground is consistent with the hypothesis that nocturnal geckos have a lower cost of locomotion than other lizards because they can perform mechanical work during locomotion more efficiently.

Energetics of swimming of a sea turtle

1976 ◽  
Vol 64 (1) ◽  
pp. 1-12 ◽  
Author(s):  
H. D. Prange
Keyword(s):  
Oxygen Consumption ◽  
Body Mass ◽  
Water Channel ◽  
Chelonia Mydas ◽  
Sea Turtle ◽  
Energetic Cost ◽  
Cost Of Transport ◽  
Ascension Island ◽  
Fat Stores ◽  
The Cost

Young (mean mass 735 g) green turtles (Chelonia mydas) were able to swim in a water channel at sustained speeds between 0–14 and 0–35 m.s-1. Oxygen consumption at rest was was 0–07 l.kg-1.h-1; at maximum swimming speed oxygen consumption was 3–4 times greater than at rest for a given individual. In comparison with other animals of the same body mass the cost of transport for the green turtle (0.186lO2.kg-1.km-1) is less than that for flying birds but greater than that for fish. From drag measurements it was calculated that the aerobic efficiency of swimming was between 1 and 10%; the higher efficiencies were found at the higher swimming speeds. Based upon the drag calculations for young turtles, it is estimated that adult turtles making the round-trip breeding migration between Brazil and Ascension Island (4800 km) would require the equivalent of about 21% of their body mass in fat stores to account for the energetic cost of swimming.

scholarly journals Effect of thermal acclimation on locomotor energetics and locomotor performance in a lungless salamander, Desmognathus ochrophaeus

1986 ◽  
Vol 121 (1) ◽  
pp. 271-283
Author(s):  
M. E. Feder
Keyword(s):  
Oxygen Consumption ◽  
Surface Area ◽  
Thermal Acclimation ◽  
Locomotor Performance ◽  
Cost Of Transport ◽  
Rate Of Oxygen Consumption ◽  
Tightly Coupled ◽  
Mammalian Lung ◽  
Locomotor Energetics ◽  
Desmognathus Ochrophaeus

To determine the effects of thermal acclimation upon locomotor performance and the rate of oxygen consumption (MO2) during activity, small (less than 3 g), lungless salamanders, Desmognathus ochrophaeus Cope, were acclimated to three temperatures (5, 13 and 21 degrees C) and exercised at various controlled speeds within an exercise wheel while their MO2 was measured. MO2 increased with speed at low speeds (less than 14 cm min-1). Although animals could sustain greater speeds, MO2 did not increase further. These small, exclusively skin-breathing salamanders could increase their MO2 9–11 times during exercise and could sustain nearly half of the oxygen flux expected across a similar surface area of the mammalian lung. However, their maximum aerobic speed was remarkably slow (14 cm min-1) and their net cost of transport remarkably large (15–17 ml O2 g-1 km-1). Thermal acclimation affected MO2 during activity, the maximum sustainable speed and locomotor stamina in different ways. During exercise at 13 degrees C, cold-acclimated animals had a significantly greater MO2 than warm-acclimated animals, but did not differ in stamina or the maximum sustainable speed. During exercise at 21 degrees C, cold acclimation did not affect the MO2 significantly, but it decreased the stamina and increased the rate of lactate accumulation. Thus, these results suggest that thermal acclimation of the MO2 is not tightly coupled to thermal acclimation of locomotor performance in salamanders.

scholarly journals Heat increment of feeding in Brunnich's guillemot

1997 ◽  
Vol 200 (12) ◽  
pp. 1757-1763 ◽  
Author(s):  
P Hawkins ◽  
P Butler ◽  
A Woakes ◽  
G Gabrielsen
Keyword(s):  
Oxygen Consumption ◽  
Energetic Cost ◽  
Uria Lomvia ◽  
Deep Body Temperature ◽  
Common Murre ◽  
Heat Increment Of Feeding ◽  
Heat Increment ◽  
Rate Of Oxygen Consumption ◽  
Free Ranging ◽  
Persistent Elevation

The rate of oxygen consumption (O2), respiratory quotient (RQ) and deep body temperature (TB) were recorded during a single, voluntary ingestion of Arctic cod Boreogadus saida (mean mass 18.9+/-1.1 g, s.e.m., N=13) by five postabsorptive Brunnich's guillemots (thick-billed murre, Uria lomvia). The birds were resting in air within their thermoneutral zone, and the fish were refrigerated to 0-2 degreesC. The rate of oxygen consumption increased by a factor of 1.4 during the first few minutes after ingestion, but there was no significant change in TB. Mean rate of oxygen consumption returned to preingestive levels 85 min after the birds ate the fish. The telemetered temperature of one fish reached TB within 20 min. This suggests that the persistent elevation in O2 over the next hour corresponded to the obligatory component of the heat increment of feeding (HIF) and was not related to heating the fish. Abdominal temperature increases after diving bouts in free-ranging common guillemots (common murre, Uria aalge) are possibly achieved through the HIF, since meals are processed at sea. Of the increase in O2 measured in the laboratory, it is calculated that 30 % is required to heat the fish, while 70 % is due to the HIF. In free-ranging birds, the excess heat provided by the HIF could contribute 6 % of the daily energy expenditure. This suggests that the HIF augments heat production in Uria spp. and thus reduces the energetic cost of thermoregulation.

Cardiovascular changes in the exercising emu

1983 ◽  
Vol 104 (1) ◽  
pp. 193-201 ◽  
Author(s):  
B. Grubb ◽  
D. D. Jorgensen ◽  
M. Conner
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Oxygen Consumption ◽  
Stroke Volume ◽  
Oxygen Content ◽  
Body Mass ◽  
Fold Increase ◽  
Exercise Heart Rate ◽  
Rate Of Oxygen Consumption ◽  
Cardiovascular Variables

Cardiovascular variables were studied as a function of oxygen consumption in the emu, a large, flightless ratite bird well suited to treadmill exercise. At the highest level of exercise, the birds' rate of oxygen consumption (VO2) was approximately 11.4 times the resting level (4.2 ml kg-1 min-1). Cardiac output was linearly related to VO2, increasing 9.5 ml for each 1 ml increase in oxygen consumption. The increase in cardiac output is similar to that in other birds, but appears to be larger than in mammals. The venous oxygen content dropped during exercise, thus increasing the arteriovenous oxygen content difference. At the highest levels of exercise, heart rate showed a 3.9-fold increase over the resting rate (45.8 beats min-1). The mean resting specific stroke volume was 1.5 ml per kg body mass, which is larger than shown by most mammals. However, birds have larger hearts relative to body mass than do mammals, and stroke volume expressed per gram of heart (0.18 ml g-1) is similar to that for mammals. Stroke volume showed a 1.8-fold increase as a result of exercise in the emus, but a change in heart rate plays a greater role in increasing cardiac output during exercise.

Energetic cost of locomotion in the tammar wallaby

1992 ◽  
Vol 262 (5) ◽  
pp. R771-R778 ◽  
Author(s):  
R. V. Baudinette ◽  
G. K. Snyder ◽  
P. B. Frappell
Keyword(s):  
Oxygen Consumption ◽  
Blood Lactate ◽  
Body Mass ◽  
Energy Cost ◽  
Physiological Adaptation ◽  
Energetic Cost ◽  
Cost Of Locomotion ◽  
Lactate Levels ◽  
Energy Cost Of Locomotion ◽  
Blood Lactate Levels

Rates of oxygen consumption and blood lactate levels were measured in tammar wallabies (Macropus eugenii) trained to hop on a treadmill. In addition, the work required to overcome wind resistance during forward locomotion was measured in a wind tunnel. Up to approximately 2.0 m/s, rates of oxygen consumption increased linearly with speed and were not significantly different from rates of oxygen consumption for a quadruped of similar body mass. Between 2.0 and 9.4 m/s, rates of oxygen consumption were independent of hopping speed, and between 3.9 and 7.9 m/s, the range over which samples were obtained, blood lactate levels were low (0.83 +/- 0.13 mmol.min-1.kg-1) and did not increase with hopping speed. The work necessary to overcome drag increased exponentially with speed but increased the energy cost of locomotion by only 10% at the average speed attained by our fast hoppers. Thus, during hopping, the energy cost of locomotion is effectively independent of speed. At rates of travel observed in the field, the estimated energy cost of transport in large macropods is less than one-third the cost for a quadruped of equivalent body mass. The energetic savings associated with this unique form of locomotion may have been an important physiological adaptation, enabling large macropods to efficiently cover the distances necessary to forage in the semiarid landscapes of Australia.

scholarly journals Energetic cost of locomotion as a function of ambient temperature and during growth in the marsupial Potorous tridactylus.

1993 ◽  
Vol 174 (1) ◽  
pp. 81-95
Author(s):  
R V Baudinette ◽  
E A Halpern ◽  
D S Hinds
Keyword(s):  
Oxygen Consumption ◽  
Ambient Temperature ◽  
Multiple Regression ◽  
Stride Length ◽  
Energy Use ◽  
Linear Increase ◽  
Stride Frequency ◽  
Energetic Cost ◽  
Cost Of Transport ◽  
Cost Of Locomotion

In the marsupial, the potoroo, multiple regression analysis shows that ambient temperature makes a minor (2%) contribution towards variation in oxygen consumption with speed. This suggests that the heat generated during running is substituted for heat which would otherwise have to be generated for temperature regulation. Maximum levels of oxygen consumption are also temperature-independent over the range 5-25 degrees C, but plasma lactate concentrations at the conclusion of exercise significantly increase with ambient temperature. Adult potoroos show a linear increase in oxygen consumption with speed, and multiple regression indicates that the most significant factor affecting energy use during running is stride length. Juvenile potoroos have an incremental cost of locomotion about 40% lower than that predicted on the basis of body mass. The smaller animals meet the demands of increasing speed by increasing stride length rather than stride frequency, as would be expected in a smaller species. Our results show that juvenile potoroos diverge significantly from models based only on adult animals in incremental changes in stride frequency, length and the cost of transport, suggesting that they are not simply scaled-down adults.

Locomotion in the abalone Haliotis kamtschatkana: pedal morphology and cost of transport

1997 ◽  
Vol 200 (7) ◽  
pp. 1145-1153 ◽  
Author(s):  
D Donovan ◽  
T Carefoot
Keyword(s):  
Shell Length ◽  
Minimum Cost ◽  
Regression Equations ◽  
Cost Of Transport ◽  
Linear Relationships ◽  
Rate Of Oxygen Consumption ◽  
Body Sizes ◽  
Locomotion Cost ◽  
Mass In G ◽  
Escape Speed

Morphological analyses of pedal sole area and pedal waves were conducted for a range of speeds and body sizes in the abalone Haliotis kamtschatkana. The pedal sole of resting abalone increased in size disproportionately with animal volume (slope of log10-transformed data, b=0.83; expected slope for isometry, b0=0.67) and length (b=2.51; b0=2.0). Pedal wave frequency increased linearly with speed, confirming that abalone increase speed by increasing the velocity of pedal waves. Total area of the pedal sole decreased by 2.1 % for each shell length per minute increase in speed. Likewise, the area of the foot incorporated into pedal waves increased by 1.8 % for each shell length per minute increase in speed. Together, these changes translated into a 50 % decrease in the pedal sole area in contact with the substratum at a maximum escape speed of 15 shell lengths min-1, relative to the pedal sole at rest. The amount of mucus secreted by resting animals during adhesion to the substratum increased isometrically with foot area (slope of log10-transformed data, b=1.08). The amount of mucus secreted during locomotion did not vary with speed, but was less than the amount needed for adhesion. We suggest that these morphological and physiological changes reduce the energy expenditure during locomotion. Cost of transport was investigated for a range of speeds and abalone sizes. The rate of oxygen consumption O2 (in µl O2 g-1 h-1) increased linearly with increasing absolute speed v (in cm min-1): O2=40.1+0.58v-0.15m (r2=0.35, P=0.04), where m is body mass (in g). Minimum cost of transport, calculated from the slope of absolute speed on O2, was 20.3 J kg-1 m-1. Total cost of transport (COTT) and net cost of transport (COTN) were high at low speeds and decreased as speed increased, to minima of 86.0 J kg-1 m-1 and 29.7 J kg-1 m-1, respectively, at speeds measured in the respirometer. Log10-transformation of both cost of transport and speed data yielded linear relationships with the following regression equations: log10COTT=3.35-0.90log10v-0.21log10m (r2=0.89; P<0.006) and log10COTN=2.29-0.69log10v-0.09log10m (r2=0.48; P<0.006), respectively.

Similitude in the cardiovascular system of mammals

2001 ◽  
Vol 204 (3) ◽  
pp. 395-407 ◽  
Author(s):  
T. Dawson
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Cardiovascular System ◽  
Body Mass ◽  
Scaling Laws ◽  
Basic Design ◽  
Experimental Basis ◽  
Additional Insight ◽  
Scaling Relationships ◽  
Rate Of Oxygen Consumption

Scaling laws governing the cardiovascular system of mammals are discussed in the present review in a manner emphasizing their experimental basis. Specific attention is given to the well-known experimental laws requiring the rate of oxygen consumption and the heart rate of mammals to vary with body mass raised to the powers 3/4 and −1/4, respectively. This review involves reconsideration and further discussion of the previous work of the writer in which these and other scaling relationships were developed from fundamental considerations. The predicted scaling laws remain unchanged from the earlier work, but alternative assumptions leading to the laws are used so as to provide additional insight. The scaling laws are shown to have their origin in the basic design of the cardiovascular system and in the basic processes involved in its working. Modification of the design assumptions of the system to account for known differences in the relative heart masses of mammals and birds is shown to lead to the scaling laws for rate of oxygen consumption and heart rate of birds.

Cellular oxygen consumption depends on body mass

1995 ◽  
Vol 269 (1) ◽  
pp. R226-R228 ◽  
Author(s):  
R. K. Porter ◽  
M. D. Brand
Keyword(s):  
Oxygen Consumption ◽  
Body Mass ◽  
Metabolic Activity ◽  
Oxygen Consumption Rate ◽  
Consumption Rate ◽  
Fold Increase ◽  
Standard Metabolic Rate ◽  
Tissue Slices ◽  
Rate Of Oxygen Consumption ◽  
Cellular Oxygen

Hepatocytes were isolated from nine species of mammal of different body mass (and standard metabolic rate). The cells were incubated under identical conditions and oxygen consumption measured. The rate of oxygen consumption (per unit mass of cells) scaled with body mass with exponent -0.18. In general, there was a 5.5-fold decrease in oxygen consumption rate with a 12,500-fold increase in body mass. The decrease in oxygen consumption rate was not due to an increase in cell volume with increasing body mass but to a decrease in intrinsic metabolic activity of the cells. This novel finding confirms and explains the decrease in oxygen consumption rate measured in tissue slices from larger mammals by H. A. Krebs (Biochim. Biophys. Acta 4: 249-269, 1950) and recently by P. Couture and A. J. Hulbert [Am. J. Physiol. 268 (Regulatory Integrative Comp. Physiol. 37): R641-R650, 1995].

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